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Revisiting Heyser

65.218.140.58

Posted on May 16, 2012 at 10:29:33
BigguyinATL
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I'm unboxing stuff and the AES compilation of Richard's work had me (re)reading all night.

one of my old "highlighers", from an Audio Magazine contribution during the time he was contributing to equipment reviews there at Audio. It was these articles that hooked me on audio technology and measurement - the year I got my Physics degree (1978)

From "Hearing vs. Measurement"

"We do not record a Hologram; we do not even pretend to record a hologram. Nor do we even pretend to play back a reconstructed holographic sound field. Yet, much of the hoopla of present audio measurement technology [and reviews] is based on the assumption that we listen to a reconstructed hologram."

He proceeds this with a prophesy, "Someday we will [have the technology] to record that [the dynamic diffraction pattern of an acoustic performance].

It has me wondering, "Why not?" 34 years later!
Three most important things in Audio reproduction: Keep the noise levels low, the power high and the room diffuse.

 

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RE: Revisiting Heyser, posted on May 16, 2012 at 18:23:50
1audiohack
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I re-read Richard regularly, from the anthology of his works. I have TEF and today am still trying to learn it's full capability. I have learned a great deal from him and his machine.

Keeps me up at night too, I don't know what's wrong with me, audio mysteries, experiments, and possible solutions run in the background of my mind non-stop. Oh well, some people play golf,,,


It's only easy if your deaf.

 

RE: Hologram, posted on May 17, 2012 at 10:04:15
geoffkait
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From "Hearing vs. Measurement"

"We do not record a Hologram; we do not even pretend to record a hologram. Nor do we even pretend to play back a reconstructed holographic sound field. Yet, much of the hoopla of present audio measurement technology [and reviews] is based on the assumption that we listen to a reconstructed hologram."

Actually, we do record a hologram and we do play back a reconstructed holographic sound field. Isn't it obvious?

 

Sorry, no hologram, posted on May 17, 2012 at 11:54:36
BigguyinATL
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It's your imagination at work.

We do not record a hologram - Though we can with what is know today as a "beam forming array" Sone of the sound bars (like the Yamaha) are probable able to present a holographic image - though the do hot attempt to do so beyond Dolby 5.1 (or 7.1) encoding - decoding. Ambisonics and a few others have also played with - non holographic recording technologies.

But - maybe you are right, the market doesn't support a trur virtual reality. What we have is "good enough".

Though I do believe that artificial acoustic spaces in video games is likely going to be the first implementation something resembling holography.
Three most important things in Audio reproduction: Keep the noise levels low, the power high and the room diffuse.

 

No need to apologize, posted on May 17, 2012 at 12:53:33
geoffkait
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I suspect many audiophiles do not hear all the ambient information including all the location cues and depth, height of the recording venue because their systems are just not revealing enough. However, on sufficiently revealing systems the holographic imaging that is part of the recording is, well, revealed. Even on mono recordings.

 

RE: No need to apologize, posted on May 17, 2012 at 13:43:06
BigguyinATL
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It is rare that the "environment" where the recording took place is "encoded" in the recoding you are replaying. Most recording are engineered from many signals recorded at different places and times, yet our minds still can recreate (Imagine) a real performance before us. A classic example is Hot August Night - Neil Diamond at the Greek Amphitheatre in LA. I can feel the concert - almost the same as when I was there - perhaps even better because my playback equipment is of higher fidelity than the venues. But the recording was made from a separate 32 to 16 to 2 track mixdown.

Or take Natale Cole - in duet with here father Nat King Cole singing "Unfogetable" - from recordings made 2 decades apart. In my basement they are there: Not ever real - Only imagined in my head from two somewhat correlated voltage signals. Heyser called the voltage signals "Flatland" - a 2 dimensional world. Our mind's observations from a host of inputs (some of them - & maybe not the the most important - are the pressure signal at our ears) create the multidimensional space and time event we enjoy in stereo reproduction.

Certainly not holography - but maybe something of the scale of 3-D movies like Avatar.
Three most important things in Audio reproduction: Keep the noise levels low, the power high and the room diffuse.

 

RE: No need to apologize, posted on May 17, 2012 at 13:58:48
geoffkait
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Well, of course, you can find exceptions, like studio recordings that are not recorded live or are manipulated to exhibit artificial imaging. I'm referring - of course - to live recordings, recorded with one, two or more microphones. Most classical pieces are recorded live in a symphony hall, for example. It is the holographic soundstage of the symphony hall that allows the listener to identify the specific hall, actually, assuming his system is capable of revealing the ambient information. Obviously, recording engineers can have different approaches and skill levels in capturing the holographic soundstage of a performance on tape.

 

RE: No need to apologize, posted on May 18, 2012 at 07:57:26
rick_m
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"Obviously, recording engineers can have different approaches and skill levels in capturing the holographic soundstage of a performance on tape."

A grand understatement!

I think there is a often a conflict between accuracy and "impressive" sound. The simplest setups seem to capture most events the best and binaural techniques appear to be especially effective to me. Mono recordings can do a very good job, as you say.

Stereo has merits, but I think the whole stereo business was more about selling gear and recordings than about musical enjoyment. A novelty as it were. Live concerts usually don't sound nearly as 'stereo' as the recordings do played back at home.

Regards, Rick

 

RE: Stereo is more about selling gear and recordings, posted on May 18, 2012 at 08:48:59
geoffkait
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There's one in every crowd. Sorry about your soundstage.

 

RE: You need to get a does of reality, posted on May 18, 2012 at 10:07:02
BigguyinATL
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Most symphony recordings are made with many microphones in the near field of a room. Not one of the recordings on your prefered system site was recorded out side the studio of many days and in many cases months.

BTW, this IS a great list os recordings. I've never heard "Dead can Dance" however.

Circle of Love (remastered), Steve Miller Band; The Who - Tommy, MCA remaster; Cat Stevens: Mona Bone Jakon (limited edition remaster); Dylan: Oh, Mercy, Hybrid SACD; Dead Can Dance/Spiritchaser (British 4A label); Led Zeppelin's Mothership; Beck's Guero
Three most important things in Audio reproduction: Keep the noise levels low, the power high and the room diffuse.

 

RE: No need to apologize, posted on May 18, 2012 at 10:11:33
BigguyinATL
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Binaural recording of large format venues (symphony halls) usually sound dull - even small clubs and churches often need some EQ and other "Helps" when played back through headphone or image processors and a stereo system. The best binaural recording are near field recordings - individual singer - small groups, in small recording studios, acoustic instruments only, please.
Three most important things in Audio reproduction: Keep the noise levels low, the power high and the room diffuse.

 

RE: Stereo is more about selling gear and recordings, posted on May 18, 2012 at 10:14:43
rick_m
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My soundstage is jess' fine, thank you.

And I admit that I enjoy it even though it's sort of an adornment.

R.

 

Hopefully you're not suggesting your reality, posted on May 18, 2012 at 12:39:05
geoffkait
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I never claimed the recordings on my list were selected for any particular reason. Certainly not because they were recorded live. You haven't heard Dead Can Dance? Really?

Note regarding Dylan's Oh, Mercy:

From Wikipedia's detailed description of the making of Oh, Mercy - "Roughly fourteen or fifteen songs were recorded at these sessions, with many of the basic tracks cut live to tape. One major exception was the lead vocals; all but two songs had their live vocals replaced by overdubs accommodating new lyrics written for the same songs."

 

RE: Stereo is more about selling gear and recordings, posted on May 18, 2012 at 16:45:26
geoffkait
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An adornment? Now I'm sure you're not an insider.

 

RE: Stereo is more about selling gear and recordings, posted on May 18, 2012 at 17:10:27
rick_m
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I liked your original post better, our hobby is all about happiness!

Rick

 

conflict between accuracy and impressive, posted on May 18, 2012 at 17:29:30
unclestu
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I believe a truly neutral system will reveal the microphone set up and the mixing. The issue is how does a listener, isolated from the actual recording event, determine that set up.

There only a few recordings which can give the listener access to that information. Kavi Alexander's recordings of the Philadelphia is well documented, as are his recordings for the Audio Quest CD's. In fact on some, like Tuxedo Cowboy, there are photos of the microphone set up ( single stereo mike). The Decca classical recordings are also well documented: the famous Decca "Tree" with outriggers. There are many photos available with a little research (including a French book on Ansermet with great photos of Orchestra de la Suisse Romane in their hall).

I am lucky in that I met a musician who played on some of the Eastman Wind Ensemble recordings on Mercury. However, you can also find photos of the recording set up in the Mercury Civil War sets ( interesting also because of the use of period over the shoulder horns, the brass face backwards in the hall and the conductor is also at the back of the hall: the woodwinds, facing forward, had to use automotive rear view mirrors to see him). Simple set up: three mikes and there is no gain riding on the mixing board as other recording engineers used ( Decca especially). All Mercs were recorded this way, apparently.

Still, most orchestral recordings will give a perspective of the conductor and NOT a listener in the hall. A quick glimpse of the microphone techniques shows them close to the ensemble and fairly elevated, almost above the conductor, where no normal listener ever has access to. When multimiked, as in Becca's Phase Four recordings, it sounds like you're in the middle of the orchestra: spectacular, but hardly realistic.

Remember that Sheffield Labs made a direct to disc recording with the mikes set up in the sitting area of the audience. It was universally panned, so much so that Doug Sax quit recording direct to discs, claiming that the "audiophile" clamor for realism was mere words.

To capture the real soundstage, transducers need to be both time and phase aligned. Very few are, and that is true no matter what price range you examine.

Pop recordings are basically reduced to psycho acoustical tricks these days. You can find older recordings with superb imaging, however. Joan Baez Live, has a three dimensionality which is rather stunning although it is quite obvious that the mike feed for the guitar and voice are different. You can hear the image shift as she shifts the weight on her feet.The same holds true for early Peter, Paul and Mary: simpler vocal parts and instrumentation are not quite as demanding. The justly praised Belafonte at Carnegie Hall also captures the live experience very well although obviously multimiked and from the stage perspective. The Audio Fidelity recording of Louis Armstrong playing the St. James Infirmary (reissued on audiophile vinyl) is superb and the album back cover has an accurate description of the recording set up including the Ampex 300 tape deck used). You can hear the movement of the position of Armstrong as he shifts from playing his horn and singing.

You can find even modern recordings with superb dimensionality: the Indigo Girls Live playing All Along the Watchtower is great, although the perspective is like you are on stage, not in the audience.

It is difficult to achieve real three dimensionality, but once achieved, the results can be truly stunning. You need to pay careful attention to the smallest details, work on the major issues, with are generally the transducers. It truly pains me to look at Stereophile's speaker test results because if such results were posted for a piece of electronics, they would be laughed out of existence.


Stu

 

RE: conflict between accuracy and impressive, posted on May 18, 2012 at 21:35:14
rick_m
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"It was universally panned, so much so that Doug Sax quit recording direct to discs, claiming that the "audiophile" clamor for realism was mere words."

I've got quite a few of them and think they are super. They were around at a time when regular records just sucked with deformed grooves taking you from one regrind lump to the next so about all I bought were "audiophile" records. Probably a successful marketing ploy because I was an early adopter of CD's due to the wretched quality of vinyl!

I enjoyed the Belafonte at Carnegie Hall when I was young and may actually have my sister's record of it stashed. I bought a CD of it but it's nothing to write home about, sound-wise.

"It truly pains me to look at Stereophile's speaker test results because if such results were posted for a piece of electronics, they would be laughed out of existence."

'Tis true. But speakers seem to get by with gross problems while electronics can sound bad with seemingly trivial errors. At a guess I think it has to do with the nature of nature. Many of the distortions in electronics don't have close counterparts in nature and so get noticed while many of the speaker problems are easy to ignore. The ilk that stand out are time smears, resonances that vex the Z-axis localization, and driver breakups. Diffraction also seems a serious problem.

My neighbor has a band and a few weeks ago a Clarinet? player was working with them. At the very first honk it didn't sound like it came out of a speaker. Once they got going I just hung out on my porch and listened to them work on a jazzed-up version of stranger on the shore while I watched the thunderheads build up over the mountains. I wish I could have recorded it but I doubt that my speakers could come close to doing those waveforms...

Regards, Rick


 

RE: conflict between accuracy and impressive, posted on May 18, 2012 at 22:08:22
geoffkait
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The cd of Belefonte at Carnegie Hall is absolutely spectacular. On a good system. Incredible soundstage, like the LP. Big as the state of Kansas. Alas, there's much to do to get digital up there with analog.

 

RE: Belafomte at Carnegie Hall CD, posted on May 19, 2012 at 07:45:58
rick_m
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Before I get excited and try to squeeze more goodie out of my copy I'd like to confirm that we are talking about basically the same disk.

This one is an RCA 6006-2-R.

Same critter?

Pressing: Sonopress A01 DD19601 IFPI L028

Close?

I have several ways to play CD's and sometime a disc will sound substantially better using one of them but I don't routinely try them all.

Thanks, Rick

 

RE: Belafomte at Carnegie Hall CD, posted on May 19, 2012 at 08:21:36
geoffkait
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I suspect the Living Stereo RCA version of the CD is the one to get. Unless the one you're referring to is a botched pressing it should be OK.

 

RE: Belafomte at Carnegie Hall CD, posted on May 19, 2012 at 10:44:43
rick_m
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"I suspect the Living Stereo RCA version of the CD is the one to get."

OK, got it added to my "cart".

The one I have says it was digitally mastered in 1989 and the Living Stereo one is apparently 2008 so maybe better?

I had an interesting experience with two CD's of the same 'take five' session from our library, one was fine, but the other was breathtaking. Perfect sound forever...

Thanks for the suggestion on the Belafonte,

Rick

 

RE: Revisiting Heyser, posted on May 20, 2012 at 11:49:31
tomservo
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Hi
Dick was a brilliant man, I owe him much and now having gone through some of his unpublished work, there are many questions I would ask him if it were only possible.
I met him twice, once at JPL when I didn’t know who he was and again with Don and Carolyn Davis who had given me an excuse to leave the tradeshow booth at AES and go with.
I could only squeak out a few words that night at dinner, I was terribly aware of being in the presence of giants like Dick, Gene P, Don and others and me being about an inch tall.

A friend was in charge of the Heyser library and it was for me a hair standing up on the back of my neck experience to go through that room and look at his test equipment and some of his unpublished work.
It was nice too eventually we were able to hire him and this month went on full time.

http://svconline.com/proav/acoustics_danley-sound-taps-top-acoustician/

In reading thorough his work, it is clear he was big on seeing things interchangeably from one perspective to another, much like how mag&phase are one view of the event while the impulse response is another view of the same exact event.
Personally I believe Dick has gotten less credit than he deserves.
In another form I explained what I saw / see starting with post #2195, #2200, #2209 here;
http://www.diyaudio.com/forums/multi-way/195124-what-ideal-directivity-pattern-stereo-speakers-220.html

Anyway, to me there are two phases of the problem, the “capture” and the “reproduction” and a “real” image requires both be correct.
He was correct in what he was saying too but a hologram is not necessary as compared to light, we are working with TINY dimensions relative to the wavelengths. SO many things depend on the acoustic size.

We hear in 3d BUT we are totally unaware of that process or how different that is compared to a perfect microphone.

In Don Davis’s “in the ear” recordings shows with amazing clarity, if you measure what is inside your ear, you find the response has all kinds of changes and comb filtering depending on the incoming angle etc.

Our ears are nothing like “flat” and everything about them would appear to be a”flaw” if see through an measurement eye.
We hear NONE of those things, rather, this is all we have ever known and so instead of hearing the comb filtering, inter ear delay and all that stuff as “flaws” we hear what direction the sound is coming from, how high it is and how far away it is, 3D perception from a two point system which normally could only resolve one axis, with processing and direction dependent errors, we hear in 3D. Playing with these effects can trick your ears to a degree but never as strong as the real thing.

To me, the reproduction side was he side where the “light went on” for me about 12 years ago.
As the full range horns at work got to be more and more like one driver a weird thing happened.
Playing a voice though one speaker, it got to be harder to tell exactly how far away the speaker was when my eyes were closed. It was still easy to hear the direction BUT harder to hear the location in depth.

When the tef measurements got to where it looked like one driver, the effect was stronger still.

This was an irrelevant thing for 99% of where the horns are used at work however I used them at home and the effect on the stereo image was dramatic.
When a loudspeaker provides a depth position que, then this detract from the stereo image. In that case (as most speaker do) when you play a mono signal which should be a single apparent source dead center, there are two additional sources” you hear in the physical depth of the speakers. If a speaker doesn’t radiate a complex field, then your brain hears the sources less and the phantom more.
Now what kinds of sources do this?

A number of hifi speakers have heard radiate only a small source identity, A Quad esl-63, a Manger on a flat baffle and to a degree some small loudspeakers where the drivers are small and close together . A hifi company has recently discovered the audibility of source identity also, google up the KEF blade concept designed around that criteria..


What radiates the identity i think is a complex field, one that provides ample clues in the differences between the right and left ear inputs. Many aspects can cause that too.
If what arrives to the R&L ears from one speaker is identical, there is no source distance information conveyed and if part of a stereo, the sources disappear into the image to a much larger degree. For a mono phantom, you do not want a Right, Left and Center sounding image.

For the skeptical, consider an experiment. Obtain a pair of small fostex full range drivers. These are necessarily limited at either end BUT if mounted on a large flat baffle, radiate as a simple source up to reasonably high frequencies. .
Move these away from the walls in the room and listen to the stereo image, these can be stunning in the depth and “real” feel of it (if present in the recordings).

Part B is the capture.
This is where it really falls flat, most recordings are not a capture of then event but a re-creation of one in the studio. You can only hear how far it falls flat when you hear something more realistic. As we hear in 3d but measure from one point in space, one can make a recording of a loudspeaker and “hear” what it sounds like without the 3d brain processing.
We used generation loss recording of speakers in the early days as a reality check. I think people would be amazed, stunned and befuddled how very few generations a loudspeaker can be used in a closed loop audition where a truly faithful device has no limit.

A really good microphone can be much more precise than any loudspeaker because of it’s dimensions and power flow amount and direction. If you use a measurement mic to make mono recordings, they can be chilling in their realism and better yet, you were there live so you have a big edge over someone else’s recordings.
The problem is you cannot easily record a live stereo image with two mics, there is no simple combination of spacing etc that “captures” the event and so most of what we hear was created with pan pots etc in the studio.

I have an approach to the issue too, while it has been a back burner project, I believe this approach is more like the idea behind a hologram although not being a massively parallel system. This works in a 360 degree capture although that requires 5 channels, 8 to cover the “up” direction too.

Pop on some headphones and try a couple of these recordings. Not the most exciting stuff but the setup is cumbersome and ugly right now and for me environmental sounds have the advantage that I know exactly what it sounded like and they are usually available. Also, these have no compression so they sound quiet and the fireworks will severely tax nearly any loudspeakers, is ruined by the mp3 process.
Try with good headphones first, FWIW, these are only the front two channels about the width of your vision.
Recordings at the bottom of this page;

http://www.danleysoundlabs.com/technical%20downloads.html

Best,
Tom Danley
Danley Sound Labs

 

RE: exactly as I was saying, posted on May 21, 2012 at 07:54:32
BigguyinATL
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Live, does not mean "encoded with holographic info" - lots of tracks (more that 4), overdubs, yup. Take "Kind of Blue" simple session recording - minimal mics and tracks - and I can pick out the "engineered" image.

When M-S mic techniques are used, the engineer can place the performer anywhere they want. - even behind you if they like! Holographic - nope - entertaining, artistic, even better than real... you bet! I love this hobby.


Three most important things in Audio reproduction: Keep the noise levels low, the power high and the room diffuse.

 

Uh...., posted on May 21, 2012 at 08:05:16
geoffkait
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You're putting words in my mouth. I am saying that the natural, intended wide, deep and high sound stage captured on the live recording, assuming it is recorded properly, is holographic in nature, not some contrivance or artificiality. Of course, everyone knows recording engineers can dick around with the sound and create artificial sound stages, too. Doh!

 

RE: Stereo is more about selling gear and recordings, posted on May 21, 2012 at 15:27:30
Tony Lauck
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Stereo, especially good stereo with soundstage, is more than an adornment. It can help one follow the polyphony.

Tony Lauck

"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar

 

RE: conflict between accuracy and impressive, posted on May 21, 2012 at 15:54:16
unclestu
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Most of the Sheffields are very good. The one I refer to was the last classical piece recorded by them.

As for speakers, they are the bane of my life. So many errors and such little attempt to correct them. One noted speaker designers who makes a line of time and phase aligned models once exclaimed to me that if perfect frequency response and phase alignment and time alignment were the goal of every designer, there ought to be a convergence of sound at a certain price point.

It doesn't happen even at a $100K. It simply means most designers are like chefs: they willingly alter the sound to please a specific market. They are NOT after true neutrality.

Stu

 

RE: conflict between accuracy and impressive, posted on May 21, 2012 at 15:58:44
Tony Lauck
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Kavi Alexander's classic Blumlein recording of Mahler's Fifth Symphony is the most natural sounding Mahler recording that I have, but for some reason some audiophiles do not like it.


Tony Lauck

"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar

 

RE: Stereo is more about selling gear and recordings, posted on May 21, 2012 at 16:28:07
rick_m
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OK...

I agree that multi-channel sound "can help one follow the polyphony". But of course that doesn't mean that I don't enjoy even mono recordings. A lot of it is matching the technology to the source, the bigger the source...

I'm especially fond of pipe organs, always the gadgeteer I suppose, and I think that a lot of their sonic appeal is spacial as you are effectively inside the beasts. Probably a candidate for surround sound but I've never had a system. I believe stereo or more can make quite a difference with certain material but I've never noticed "pinpoint" imaging and such in concerts, actually I pretty much have to watch for the scraping of the bows to get a fix on the sound.

That being the case, I probably should be buying DVD's rather than CD's and SACD's. If I really want to go to the next level seeing seems more important than more audio channels.

Regards, Rick

 

RE: conflict between accuracy and impressive, posted on May 21, 2012 at 19:43:16
rick_m
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"It [lack of convergent speaker performance] simply means most designers are like chefs: they willingly alter the sound to please a specific market. They are NOT after true neutrality."

I suppose that's part of it. But even though my experience is microscopic compared to yours my take on speakers is that there are many factors in play which complicate optimizing any particular system. To wit:

-User preferences.
-Musical genres.
-Loudness.
-Environment.
-Significant others, including pets.
-Industrial design.
-Cost and availability.
-Perceived support.
-...

But, despite all that I think there is a "house sound" and philosophy that can be useful for some periods of time. I'm on my second pair of similar Infinity speakers and so have had similar sound for... 34 years. It took a while because I ran low on fingers. But now the company's gone. Sigh. But I know that I like acoustic suspension woofers and film tweeters. But I also like AS woofers and good metal tweeters. What I loath are bass reflex (reflux) boom boxes and tweaters that breakup.

But does that mean they are more accurate than all other options? I doubt it. Stu, I think it's all a tradeoff and the key is finding technologies or implementations whose strengths you love and whose weaknesses you can tolerate.

One thing I've seen lately is more companies making very similar speakers just in different sizes. I really like that. A living room sized speaker isn't appropriate for a bedroom or study, I want the same sound but in different sizes and SPL's.

So... Am I typical or goofy? How many of your customers come in wanting something like they have only better or for an alternate environment vs those who want a whole new deal?

Not that there is any "right" answer of course, the hobby has many facets..

Regards, Rick



 

Ah...., posted on May 22, 2012 at 16:58:13
unclestu
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Would you compromise for an amp that has horrible specifications simply because it looks nice on the rack?

If music is the ultimate goal, I do not believe compromise is the answer. Musical Genres should not make a difference, and in my mind, any genre should sound good if the system is truly neutral. Environment? Perhaps, if you live in an absurdly extravagant home with a cavernous listening room or a hovel with a prison cell for a listening room. Industrial design is a non issue for me. Loudness, well if you are trying to reproduce rock concert levels, perhaps, but that's not for me: precision in a playback transducer means for my listening, lower volumes are satisfactory, and I still get a large soundstage to boot.

My chief complaint is that no reviewer has ever really taken any speaker design to task over obvious compromises in design and presentation. They can not or do not hear what influences these compromises present to the listener.

Again I harp on the case of Amar Bose who came out with a 500 watt receiver with 5% distortion because he claimed that 5% distortion was inaudible. It certainly was inaudible with a pair of Bose 901's because they had 5% distortion measured at one meter as evidenced by the reviews which came out at its introduction.

If that is typical, why bother with 104 dB s/n ratios in CD players, and why search for vanishing low distortion specs? We need a measure of common sense in audio, and, as I see it, speakers are among the weakest point.

of course YMMV

Stu

 

RE: Ah...., posted on May 22, 2012 at 18:26:54
rick_m
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"Would you compromise for an amp that has horrible specifications simply because it looks nice on the rack?"

Of course not Stu. In fact I truly don't care what my power amp looks like since it lives on the floor of a closet.

But speakers are another matter, they pretty much have to be in the room with you and that often means tradeoffs. That's where knowing the genre of main interest may help. Like you I don't need to reproduce ultra loud music because my main interest isn't rock concerts and sadly loud sounds now hurt my aged ears and I want to keep what dynamic range I have as long as possible! Even beyond sound the speaker concerns also extend to other's in the house and Wives, Kids and pets gotta be considered. At least a little...

"We need a measure of common sense in audio, and, as I see it, speakers are among the weakest point."

I suppose so, they surely have been traditionally. But I wonder if they aren't getting overall better, especially the affordable ones. I haven't been in the market for so long that I don't have a clue.

As far as distortion goes a lot depends upon it's nature. Usually speakers are the most linear for small displacements and run into troubles when loud. Since our ears also follow that pattern we may be less annoyed by it than by, say, crossover distortion in amplifiers.

Temporal anomalies and dispersion shifting over frequency are sort of speaker specialties and I think they can really snap you out of the music and make you aware that somethings artificial. Artifacts tend to do that...

Reviewer-wise I think that the readers would benefit most from having specialization where each only does a class or two of components. I realize that that might be more boring for them but that doesn't bother me a whit if they are paid professionals, it just goes with the territory!

I have a hard time seeing how any useful lateral comparisons can be done without systematic evaluation and changing other things in the system willy-nilly eliminates doing that effectively. Additionally a small library of 'reference' components should be kept to close the loop from time to time.

As you can imagine I don't put too much stock in reviews, well except for "Sam Tellig"'s. One piece of advice used to be to find a reviewer with similar ears and tastes and he seems to be mine... But he would be even better with a good testing structure!

Regards, Rick

 

You're wasting your time..., posted on May 23, 2012 at 08:56:35
Presto
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...this is more blind leading the blind. They believe the venue acoustic properties are encoded in the recording and their stereo magically RECREATES the entire hall IN delicious 3D as if there was some sort impulse response convolution going on. If you can take some audiophiles and put them in a room and have them listen to recordings BLIND and tell me what hall the recordings were made in (if they were made in a hall at all) I will print this post off on 20 pound bond paper and eat it. You'll never see such an exhibit. They all are sitting there reading the liner notes - "Ah yes, indubitably, this is the Sydney Opera House... I knew it! I recall the acoustics very clearly... haw haw poo poo. Earlier that evening we had scallops prepared by the famous chef..."

Bla bla bla bla.

The closest thing stereo can do to "recreate" an "event" is the properly HRTF equalized binaural recording which is best realized with headphones rather than loudspeakers in room. Loudspeakers complicate the situation too much with their unique acoustic response (phase AND amplitude) and polar response which is affected by room boundaries, geometry, listening distances etc.

A $200 pair of headphones can reproduce the ambient info of a binaural recording better than even a $100,000 pair of loudspeakers so long as HRTF equalization is properly employed.

"If you can't hear (read: imagine) what I am hearing (read:imagining) then your speakers are simply not revealing enough..." is what everything written on this entire site boils down to. It's how all arguments begin and end. Remember this when you are considering how much time you spend debating here. The guy you're debating with right now, for example, is the audiophile equivalent of Jo Jo's Psychic Alliance.

Always consider the source, grand-daddy always used to say...

Cheers,
Presto

 

RE: conflict between accuracy and impressive, posted on May 23, 2012 at 09:09:47
Presto
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Bang on Stu:

"In fact on some, like Tuxedo Cowboy, there are photos of the microphone set up ( single stereo mike)."

Single stereo mic, although not perfect, is the closet thing an audiophile will get to a recording that has capture any semblance of the acoustic properties of the venue (a binaural recording). After that, it's two separate mics. After that, it's multiple mics all over the darned place with mic mixers with God knows what relative mic polarity - in which case all bets are off.

But let the converted believe. If they're having fun, why shatter the illusion for them? Stereo "imaging", in the best case, is the visual equivalent of looking into a circus tent mirror. You barely recognize yourself. Instead of audiophiles being amused at soundstage placement, they strive to believe that what they are hearing is the equivalent of sitting there. If that's the case, I have one very fundamental question:

Which seat?

Besides. If you dare to object, your stereo is then damned - it's cast off to "not revealing enough land".

Not revealing enough indeed.

Cheers,
Presto

 

RE: You're wasting your time..., posted on May 23, 2012 at 11:08:50
geoffkait
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Your words echo a lot of audiophiles, who apparently have never had the opportunity to hear a quality system. Pity.

 

And there it is., posted on May 23, 2012 at 14:16:12
Presto
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Ah, the famous "You've never heard a quality system" aka "your system is not resolving enough" routine.

Like I said. Begins and ends with this.

 

Kavi's, posted on May 23, 2012 at 17:58:30
unclestu
Dealer

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recording technique sounds best if the speakers are at a 90 degree angle pointed directly at the listener. When oriented as such, the hall realism is very natural and rather spectacular at least to my hearing. Unfortunately not many want to reorient their speaker for one recording.

Another source of very realistic recordings is Kimber Kable's IsoMike technique. AS they now have professional musicians being recorded, the sonic realism makes them a joy to listen to.

Ray Kimber's approach is quite different: he tries to place the mikes in the typical position one would have their playback speakers. Unorthodox, but it seems to work very well. On one of his demo discs he has a track entitled Roll Call, whereby the choir, standing in a circle around the microphone array, simply calls out their individual names. Set up in surround sound, the presentation is extremely realistic and Kimber's Isomike technique utilizing four speakers in a surround sound mode has the most natural and realistic soundstaging I have heard thus far.


Stu

PS: It should be pointed out that Kavi's Russian recordings used a digital recorder. IIRC, Kavi actually borrowed the system Kimber uses. Prior to that, Kavi used a custom EAR one inch tape drive tubed reel to reel recorder. I'm not sure if Kavi used the same dual recorder set up that Ray uses, however.

 

We've, posted on May 23, 2012 at 18:15:23
unclestu
Dealer

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become apologists for speaker performance, in my opinion. Crossover distortion for an AB amp is nothing compared to crossover distortion for speaker designs.

I have posted over on Tweaks about placing mu metal strips between multiple drivers in a speaker system. The increase in clarity is astounding as the mu metal cuts the magnetic interference between the drivers (properly installed of course). I see no manufacturer implementing such a tweak. I have posted on the simple changing out of black iron screws to nonmagnetic ones, either brass or stainless. Very few manufacturers follow suit, although you can actually hear the soundstage changing if you play music while replacing the screws one by one.

I find that the typical designer hops on his computer and simply downloads an appropriate crossover design, sticks in speaker parameters and is pretty much done with the model. They seem to take the computer's word as being sacred and do very little independent investigation on their own (believe me, I have spoken to a myriad of designers over the years and while I do not claim any special knowledge about speaker designs, I am still shocked by the relative ignorance, in general, by many lauded designers).

As for speaker volume, what normal listener can ever have playback at 125 dB? Your neighbors, let alone your significant other, would can the system almost immediately. That being said, I see many "audiophiles" preferring to play extremely loud because loudness actually conceals many sins. If the system is truly neutral and coherent, woofers and tweeters are in proportion no matter what the volume is. Midrange is appropriately balanced, too. Too many systems are not balanced at all except at very loud levels.

I hear this all the time when I attended CES and many audio stores. In fact serving an "apprenticeship" at an automotive audio shop taught me one thing: crank up the volume of whatever product you want to sell, and you pretty much have it sold. Guy could come in looking for a pair of speakers but you could sell an equalizer that way..... Unfortunately, the same sales approach pervades even home stereo. And unfortunately home theater hasn't helped any: exaggerated bass and treble are the typical norm and many have come to expect the same "sound" from their stereo.


Stu

 

That willing suspension of disbelief, posted on May 23, 2012 at 18:22:56
Tony Lauck
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Geoff's right. For some people even the best recording and a matching "resolving" system won't matter.

"That willing suspension of disbelief for the moment, which constitutes poetic faith."

Tony Lauck

"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar

 

The idea that the, posted on May 24, 2012 at 08:50:37
Presto
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...acoustic "information" of the venue is captured in such a way that it can be recreated is wrong.

Look, imaging is wonderful. It's fun. It's neato. It's up, down, back side to side, hell last night I had sounds coming from beside me. Must be some phase-related Q-sound type effect. Damned impressive.

But the physics is the physics Tony. You're grounded in physics are you not? Look, if someone is using two mics then they are getting the closet thing to a binaural recording as you can get. Why the fuss about binaural recordings? If the mics don't "hear" the venue (and of course the sounds in it) the way humans do, then it's not going to be anywhere near accurate spacially. Yes, you get the impression there are performers in front of you and off to the left and off to the right and towards the back. These are a result of relative levels between left and right channels, reflections in the roof, phase distortion from the speakers, interaction of speaker polar patterns determined by speaker spacing... distance of speakers to back wall.

If you can change your soundstage by purchasing new speakers or just moving them about the room, how can one then say what accurate is? If the mic-to-mic distance on a two-mic soundstage changes soundstage attributes, then what is the "correct" distance to capture the venue's acoustics so they are accurately conveyed? The answer is "you can't". The recreating is a nifty simulation, some more real and convincing than others but a simulation nonetheless.

Look, I am all for "tricking the listener" into FEELING like he is there. Get it all the time. Wonderful effect caused by artifacts, delays, phase shifts and all kinds of constructive and destructive interference. But to say that "the venue acoustics are captured on the recording and if you have a RESOLVING ENOUGH SYSTEM you will magically extract this wonderful information".

There are tricks to recreating room reverb times and it has to do with capturing an impulse of the space and convolving that impulse with the music material. Assuming the guy will use cans, the time-domain info needed to SIMULATE the acoustics of the venue is indeed captured. I say simulate because when you're listening to cans in a 8 x 10 room you're not in a cathedral, so obviously getting cathedral sound is indeed a simulation. Now if he's NOT using cans, he has two additional problems. He's got his OWN room acoustics and he's got speaker attributes when added give you the "speaker-room" equation. To use speakers in a room and impulse response convolution to simulate a space, you would first need to remove the amplitude and time-domain errors of the speaker/room combination - one could create a single impulse that removes the listening room and adds the listening space. I'm not a huge convolution fan so I never got quite that far. Using cans will obviously be much easier which is probably why binaural recording fans seem to more often skip speakers.

"Transported back to the original event". Maybe emotionally, but not acoustically. Believe, guffaw, point and laugh all you want. The emperor has no clothes again. Recording methods and speaker/room interaction obfuscate "room" info, if what is there on the recording is even worth a lick "spacially" in the first place. Most concerts I've seen have mics on instrument groups as well as mics for individual instruments. Now c'mon - tell me this recording setup was done with capturing the venue in mind. Sure, you have some ECHO captured, but when you mix all these mics what you have is a bunch of echos who's time-domain info is now completely irrelevant. You have multiple locations from which you are recording - spacial game is over. Neato effect? Still there. Acoustics of venue captured? Nuh-uh.

But hey, if you believe your stereo is a transporter beam that takes you back to the hall, then wow, what the hell are you doing typing on here?

Cheers,
Presto

 

RE: The idea that the, posted on May 25, 2012 at 08:02:15
Tony Lauck
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"The idea that the ...acoustic "information" of the venue is captured in such a way that it can be recreated is wrong.

A large amount of information about the acoustics of the original recording venue can be captured by two microphones. There are certain spatial symmetries that can't be resolved, but in general if one puts a source of impulses at various places in the sound field the recording will change and in such a way that it is possible (e.g. by a computer) to recognize points from these patterns. If sufficient additional information is provided, e.g. a calibration grid, then it will be possible to locate the sound sources in real space. Similarly, if the walls are moved the patterns will also change, making it possible in principle to recognize hall acoustics. Left and right information is obviously present, but so is depth (it even appears in mono). There is also height information because of reflections off the floor or ceiling.

Note that I am talking solely about information that's on the recording, not whether (or how) it can be "decoded" by the human ear/brain/mind system. The sonic patterns at one's head when a stereo is played are not the same as those in a seat at a live concert, so they will have to be decoded different. The ability to "hear" microphone patterns on recordings, for example, is not something that an untrained listener can do, but an experienced recording engineer can do this with a good playback system.

You can tell if a system is "accurate" is by playing a large corpus of reference recordings. This is the way that mastering engineers fine tune their systems and is something that can not be done by measurements alone, although measurements play an essential role in the setup process. Recording and playback of music are an art as well as a science.


Tony Lauck

"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar

 

RE: The idea that the, posted on May 25, 2012 at 09:16:38
Presto
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Tony:

I don't disagree with what you're saying in your last post. Let me clarify:

Recreate Soundstage / venue acoustics: not correct
*Simulate* venue acoustics: possibly, to some extent

And yes, I agree that 2-mic methods are going to give one a chance while mixed multi-mic recordings are just a facsimilie. That said, the two mics and how they are positioned will greatly affect the perceived "stage". Even so, two mics x feet apart is going to give an entirely different effect than a stereo mic or two mics placed in closed proximity but at different angles.

Even with 2-mics there are a number of different methods.

To say that a system is "set up correctly to play two mic recordings properly" is therefore a really big stretch. Sure, you can play with placement, toe-in and distance to back wall depth. But "correct"? I think reviewers and many philes have crossed the line into dream land once again.

Cheers,
Presto

 

RE: The idea that the, posted on May 25, 2012 at 09:38:04
Tony Lauck
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Agree, "correct" doesn't apply to sound stage, as it is an illusion that depends on the listener. "Preferred" would be a better word.

However, when it comes to tonal balance, e.g. high frequency roll off or the lack there of, there is more of a natural reference, at least for acoustic music. The perceived tonal balance should correspond to the perceived tonal balance at some seat at a live performance, and the seat in question has to be somewhat plausible in light of amount of reverberation and volume. Unfortunately, recordings aren't made to a standardized playback, and if they are miked, mixed and/or EQed to sound good on a mastering system with one high frequency roll off they won't sound so good with a different one. (I presume that the reference system used to monitor the Mercury Living Classics recordings was somewhat rolled off based on the brightness of these recordings, compared, say to Lewis Layton's work on RCA.)


Tony Lauck

"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar

 

RE: The idea that the, posted on May 25, 2012 at 10:13:36
Presto
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Tony:

Although there is not an overall "EQ" transfer function that would please everyone, most people seem to like a downward tilt over the entire range - this could well be to compensate for most people simply not finding a perfectly flat response to be natural sounding. Myself, I like "flat" but after doing baffle step compensation and tweaking things high-frequency shelf filters and tweeter level pad (voicing you could call it) the response is anything but flat.

In a perfect world, the recording engineers would step into a room next to the studio - a audiophile sized listening room with two speakers and a chair set up with audiophile placement. If they heard their mixes on this "system next door" I am sure the number of decent recordings would go up dramatically. Trouble is, they are eq'ing to studio monitors that are flat, but they are listening nearfield. They might switch from nearfield monitors to larger house monitors, but in the end, are they ever mixing for systems like the ones we as 'phile assemble? And are not many studio rooms on the dead-side, which could be a reason why some recordings are excellent except for a sizzling hot high end?

I have recording equipment here... you just gave me an idea...

Cheers,
Presto

 

RE: The idea that the, posted on May 25, 2012 at 10:39:34
Tony Lauck
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The reason why people prefer slightly rolled off response is that the studio monitors used have similar response. Most CDs (including classical and probably even some so-called "purist audiophile" recordings) are EQ'd at some point in the "mastering stage". (The correct term for this stage is "pre-mastering" as the actual mastering takes place at the manufacturing plant.) This EQ is needed because the earlier stages of processing produced imbalance results, either due to accidents or because errors were deliberately made to offset errors in the inferior monitoring and room acoustics at the recording venue or mixing stage.

There are some very subtle and complex relationships between equalization and sound stage. After making lots of adjustments on the electronic crossovers of my Focal satellites and sub woofer I still was left with a few peaks due to room modes, at 40 Hz and 127 Hz and a small peak at 781 Hz. After living with these for the past two months I decided yesterday to see what would happen if I took these out with a parametric equalizer. As expected a few recordings that were bass heavy because of peaks at similar frequencies were tonally improved. This was to be expected, but what was much more surprising is that the sound stage improved greatly in depth, as my mind was no longer cuing in on the room resonances of my small listening room and hearing past them to more of the ambiance on the recordings.

To do this EQ I had to use the iZotope parametric equalizer that comes with Soundforge, a pain in the ass process that takes a minute to process each recording to be played. Unfortunately, this software is tied to Soundforge and is not usable as a VST plugin that I can use with my player software such as cPlay.

Do you know of any good parametric equalizers that run as VST plug ins? Are you still recommending the one from aixcoustic.com?

Tony Lauck

"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar

 

RE: The idea that the, posted on May 25, 2012 at 12:00:30
tomservo
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I think you’re on the right track, remember when CD’s were introduced, they “had to” sound better than the LP’s they were targeting to replace and an easy way was making a brighter recording that anyone would notice as “more extended”. Get a copy of Michel Hedges Breakfast in the field and hear an early a very clear but very bright recording.

Part B I think Is that harmonic distortion is normally to the high side of the fundamental producing it so in the case of loudspeakers, one finds the harder they are driven, the brighter they sound and eventually sound bad. As the size of loudspeakers has fallen and power handling climbed and lacking a standard measure of linearity or usable loudness, what we have now are speakers that are often less signal faithful than the old days.
An Altec horn for example had essentially no power compression because if you drove it that hard, the wire came off the voice coil at ~ 125-150C, now days some VC adhesive will tolerate >>350C (Rdc doubles at about 230C).
Also. I do think we “hear through” obstructions without being conscious of it and so if you remove a que that the speakers or room add, what you hear is a more faithful image while you were previously unaware of that same que.
I would offer that for the most part, if you can measure and correct your speakers based on outdoor / anechoic measurement, then you can be pretty sure that what your doing will fix both mag and phase simultaneously.

To the degree what you’re trying to eq is caused by a delayed signal (reflection) combining with the direct, you can’t really fix these as they are not a minimum phase problem. In the old days, they said only cut peaks and bumps, NEVER try to fill a sharp deep notch as that is the signature of a comb filter (caused by a delayed signal).

While the miracle of DSP and incomplete explanation or limited measurement resolution will make it appear you can “fix everything” the absolute best one can do is fix it in one specific spot where the measurement was taken and often making it worse everywhere else.

The “fixed” location is limited to about ¼ wavelength in size for the highest frequency being corrected so it is truly futile (acoustically) fixing it with dsp when the listening area is much larger than the wl in size. At 20Khz, the wave length is about 5/8 inch..
Fixing the source is the best way I think. Can’t help on a plug in but would offer that LSPcad can emulate a number of speaker controllers which have parametric’s , the down side is most dsp units are somewhat different when you call for a given filter set or alignment.
You can also listen to music through that alignment if you want. For work, I take the actual unit and measure / adjust the eq until it overlays on the transfer function or response I need.

Also, you could save the impulse response for the correction and convolve it with the music, the ”Gratisvolver” at Cat acoustics is free anyway. That also appears to be a way of transferring “what a speaker sounds like” as well as the speakers impulse response can be convolved with music too, sort of a software way of doing loudspeaker generation loss recordings we do at work.
Best,
Tom

 

"Breakfast in the Field" you say?, posted on May 27, 2012 at 08:28:35
E-Stat
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Get a copy of Michel Hedges Breakfast in the field and hear an early a very clear but very bright recording.

The original analog version from 1981 or the later CD copy? I have both. In this case, I think the "villain" is the minimal processing done on the recording. Your post piqued my interest because I find that overall, the original analog copy is an incredibly natural sounding recording - albeit a touch bright (an easy thing to cure). On The Happy Couple, you can so easily visualize his hands moving in his inimitable way. I've had to good fortune to see Hedges live three times before his untimely accident.



In another post, you mention the KEF Blade. I was in the Bay area earlier this year and noticed a hi-fi shop in downtown SFO nearby the Ruth's Chris where my wife and I had dinner. Since it had literally been years since I've set foot in an audio dealer, we walked over. They graciously played a couple of tracks on the Blades. As a coherency freak, I found them good in that respect. But, the apparent image size was tiny and very directional. Not my cup of tea. :)



 

RE: "Breakfast in the Field" you say?, posted on May 27, 2012 at 08:32:28
geoffkait
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I agree, the recording is not bright. Same is true of all or most Windham Hill Recordings.

 

There are exceptions..., posted on May 27, 2012 at 08:41:10
E-Stat
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Still, most orchestral recordings will give a perspective of the conductor and NOT a listener in the hall.

Jack Renner of Telarc fame took a different approach. I had the good fortune of participating (in a very minor way) to the ASO recording of The Firebird. He used a minimal set of mikes with a couple in the audience area where I sat as official "timer". Needless to say, I was reminded to be completely silent! No funky placement as with the Mercurys although the usual acoustic shells at the back of the orchestra were rolled back.

That was also a cool event to meet Dr. Stockham along with seeing and hearing the Soundstream recorder between takes. I remember Shaw giving the clarinet player grief for one take of his solo in the Borodin piece. He later nailed it to Shaw's satisfaction. :)

 

RE: "Breakfast in the Field" you say?, posted on May 27, 2012 at 16:31:18
tomservo
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Hi
I have an early CD of it (and one of his others).
I like the recordings very much but are what I was talking about as to how they made the early CD voiced differently.
In that case, on speakers that measure flat is a very bright recording and bright I think “so it sounded better”.

I have not heard the Blade speakers myself but they did talk about hearing the radiation shape but they didn’t provide any directivity measurements that I recall.
While I noticed the effect developing the Synergy Horns speakers for work, they are constant directivity and radiate as if they had one driver..

 

RE: Revisiting Heyser, posted on May 27, 2012 at 17:21:22
briggs
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5 - 8 channels. Um. Yeah. Sure. Great!

 

RE: "Breakfast in the Field" you say?, posted on May 27, 2012 at 17:32:14
E-Stat
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...they are constant directivity and radiate as if they had one driver..

Yes. Back to the Blades for a moment, they seemed quite coherent even if it was a coaxial mid/tweeter and two side firing woofers. It just suffered from shrunken image size.

I'm thinking that would not be the case with an SH-60. Maybe two would be better.

 

RE: The idea that the, posted on May 28, 2012 at 09:15:04
Presto
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Tony:

Wow, that was a while ago "AIX Acoustic". Good memory!

I am running DSP crossovers almost exclusively now, except when I pop in my passive-crossover based reference monitors to see how far I've wandered off the beaten path. ;) As such, I can do pretty much any equalization imaginable right in the crossover.

I might have to listen to the AIX acoustic crossover again - it's been years!

Cheers,
Presto

 

RE: The idea that the, posted on May 28, 2012 at 13:21:09
Tony Lauck
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Not memory on my part. AA search. :-)

I got it to work and set it up for a similar response to what I was getting out of the iZotope parametric EQ in Soundforge. There were a few differences, however, i.e. "bandwidth" is specified instead of Q. Also I am suspicious of the AIX plugin because it's "flat" position had about 0.5 dB of gain. Not something any serious DSP expert would ever do.

I need to do some more tests to see if this gain problem is the only problem. At least it interfaces with Soundforge and cPlay.


Tony Lauck

"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar

 

RE: Revisiting Heyser, posted on May 30, 2012 at 06:54:35
tomservo
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“5 - 8 channels. Um. Yeah. Sure. Great!”

Not sure if you actually tried it, but put on headphones and play the recordings at the bottom of this page.

http://www.danleysoundlabs.com/technical%20downloads.html

Hopefully, these (the stereo image) will sound unusual to you but those are the front two channels more or less the width of your vision.

With the right speakers, you can reproduce this in a living room.
With 3 more channels, on can capture a 360 degree view of the sound field or with 8 a full hemisphere. The effect is pretty cool actually, it sounds like you are somewhere else.
Best,
Tom Danley

 

I've been a believer in this..., posted on May 30, 2012 at 16:46:42
Presto
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"The problem is you cannot easily record a live stereo image with two mics, there is no simple combination of spacing etc that "captures" the event and so most of what we hear was created with pan pots etc in the studio."

I've been a believer in this all along!

Cheers,
Presto

 

Two microphone stereo recordings, posted on May 30, 2012 at 19:54:39
Tony Lauck
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Contributor
  Since:
February 24, 2009
"The problem is you cannot easily record a live stereo image with two mics"

This can work just fine, assuming good acoustics, engineering and musicians. The Water Lily Acoustic orchestral recordings of Mahler's Fifth and Shostakovich's seventh symphonies are excellent examples of this.

On a smaller scale some of the Chesky jazz recordings have very natural stereo and were made with one stereo microphone.



Tony Lauck

"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar

 

RE: Two microphone stereo recordings, posted on May 31, 2012 at 06:28:27
tomservo
Manufacturer

Posts: 6574
Joined: July 4, 2002
Hi Tony
This is a topic I love!
It is true, if you take two microphones there is no combination of spacing that permits the genuine item to be captured accurately.
The Blumein technique comes a lot closer, it is a special case of two vertically stacked elements (with open backs usually) and unlike a simple pressure mic have a figure 8 pattern.

This does two important things, one, it is “mono compatible”, a single sound source produces the same signal phase / time on both mics.
This means you can sum them and not have all kinds of comb filtering that is present when you sum two or more mic signals that are in separate locations. In the horizontal plane, they are in the same location in time.
Two, the figure 8 pattern provides amplitude shading according to horizontal angle and this is why a signal to the left is louder on the left channel. Two pressure microphones in very close proximity produce the same signal but have no directional discrimination.

The weakness in that design is that that each mic has a figure 8 pattern while what you would like to capture is only what is in front, not the rear. Also, the shape of the figure 8 only allows a fixed degree of amplitude shading vs angle and so is limited to a two channel system as is used currently. Cardioid mics can be satisfying but their patterns change a lot vs frequency.

The microphone array thing I am working on is along this line but done an entirely different way.
It allows the sound to be detected as if it were from one point in space but can be divided into a large number of channels if needed.
Also, where the Blumein is not coincident in the vertical plane, this can be made to capture a full hemisphere from one point in space.
As you enjoy “stereo” image, please pop on a set of headphones and try a couple of the recordings they put on the web site at work.
These have no compression so you may have to turn the volume up to get to a real sounding level. Try the Harley or Trains and keep in mind this is a work in progress and only the front image, more or less the width of your vision.
Let me know what you think.
Best,
Tom
Recordings at bottom of the page;
http://www.danleysoundlabs.com/technical%20downloads.html

 

RE: Two microphone stereo recordings, posted on May 31, 2012 at 09:23:36
Tony Lauck
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The sound out the back of the figure 8's can be a benefit, as it provides hall ambiance. If this proves excessive, the microphones can usually be moved closer.

The big downside of minimal microphones is that the musicians are responsible for the balance and it won't be easy to fix their mistakes. It will be impossible to "Autotune" bad vocalists, but that's a good feature, IMO :-)

Comb filtering is a big problem when spatially separated microphones are mixed into a single channel. It is less of a problem when each microphone has its own speaker, as the ear hears these two cases differently at high frequencies.

My late wife loved your "Train Start" recording. I will listen to the newer ones when I get the chance. But it will be on speakers, as I don't have any decent headphones, just a handset that I use for Skype.

Tony Lauck

"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar

 

Array systems for meassurement, posted on May 31, 2012 at 12:05:09
BigguyinATL
Manufacturer

Posts: 2438
Joined: April 10, 2002
could also be used for recording, and reproduction. Onfotunately the standard array mics are a little noisy for music recording and a high quality low noise microphone would e costprohibitive at Qty 90.

And yes Blumein array is -IMO a nice recording technique - especially useful for the ambience feed to a recording or medium sized live events in the somewhat near field. A second (or 3rd) X-Y array can be used with appropriate delays to mix in ambience from the rear of the hall. For engineered recordings, M-S mic configurations for the individual performers and instruments are great - you can "place" the track anywhere adjusting the levles and delays relative to other tracks and the mix down to Mono is honest.
Three most important things in Audio reproduction: Keep the noise levels low, the power high and the room diffuse.

 

RE: Array systems for meassurement, posted on June 1, 2012 at 16:26:42
zako
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Posts: 777
Location: Mo.
Joined: March 29, 2004
ABOVE is a reference to Belafonte at Carnege Hall... As being a stereo recording... IT IS NOT and the photos at the performance shows that,,, Harry is holding one mic and walking back and fort on stage,,,His band has two mics close to the floor not even matched spaced a couple of feet apart... Two other mics above his head are faceing away from his body tward the back of the stage,, A string section is grouped in another position on stage,,, NO imageing is produced,,,Also WHAT IS MOST INTERESTING ALL APPLAUSE SEEMS TO COME FROM THE FRONT ON STAGE WITH BELAFONTE,,...

 

What's so surprising , posted on June 1, 2012 at 17:57:56
unclestu
Dealer

Posts: 4197
Joined: April 13, 2010
about the applause coming from the front? You just pointed out how the mikes were placed. If they were cardioid types, that is to be expected.


Stu

 

RE: What's so surprising , posted on June 2, 2012 at 13:44:47
zako
Audiophile

Posts: 777
Location: Mo.
Joined: March 29, 2004
The mics are in the photos and the manufacture can be identified..plus what way they are pointed,,So STEREO claimes are false....BELAFONTE is Obviously MONO..

 

RE: What's so surprising , posted on June 2, 2012 at 13:52:34
zako
Audiophile

Posts: 777
Location: Mo.
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The mics in the Belafonte concert are not pointed at the audience,,So how did the audience appear in front of you in reproduceing the mix of the recording.. When Belafonte asks the sections of the audience to respond,,Why did the section NOT give proper locolazation cues on the record ??

 

RE: "Belafonte is Obviously MONO", posted on June 2, 2012 at 18:09:30
geoffkait
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Posts: 7662
Location: northern Virginia
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There is a mono version of Belafonte at Carnegie Hall, but the stereo version actually is stereo, as in RCA Living Stereo.

 

RE: "Belafonte is Obviously MONO", posted on June 2, 2012 at 19:21:32
zako
Audiophile

Posts: 777
Location: Mo.
Joined: March 29, 2004
Yes I know that...I have both,, But it does not answere my question.. RCA is pulling the wool over your eyes claiming a full stereo recording,,When on stage,,A full stereo mic setup did not exhist,,

 

You're making, posted on June 4, 2012 at 18:42:56
unclestu
Dealer

Posts: 4197
Joined: April 13, 2010
mountains of molehills.

If the mikes are omnis then the phenomenon you mention has an obvious explanation.

If the mikes are your typical cardiod pattern, which is a heart shaped pattern with the indentation being at the mike, you are capturing the sound off the sides and slightly to the rear.

Now take applause: can you identify individual people clapping? I don't think so. Applause is basically random noise and it literally echoes off the sides of the venure. Directionality concerning applause is basically impossible, not to mention that you have tremendous issues with phase, particularly wince applause tends to have severe "bounce" off side walls.

A normal mike will pick up a lot of the applause as it echoes off the side walls and the reflectors over the performers. The mike can not distinguish individual people clapping ( at lest for normal clapping) and so your ears perceive the clapping as being being all around.

Next time, try standing on a stage while the audience is clapping. The sound completely engulfs you, even if you are on stage.

If you want to hear applause as it should try a discreet four channel recording, like Kimber's Iso mike recordings.



Stu

 

RE: The idea that the, posted on June 5, 2012 at 09:11:38
Presto
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Posts: 5328
Location: Canada
Joined: November 10, 2004
Thanks for bringing that to my attention Tony. Some basic testing (in versus out) is called for here. Simply recording the output of the plugin in the digital domain should do it... I'll see what version of this EQ I have.

Cheers,
Presto

 

RE: The idea that the, posted on June 5, 2012 at 10:20:19
Tony Lauck
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I am no longer seeing this difference in gain, so perhaps the problem only appears in certain conditions. Or perhaps it could have been "cockpit error" on my part when I first started playing around with the program.

I've got the EQ running as a VST plugin under cPlay and this is definitely improving my sound, cleaning up some muddy bass on some recordings as well as improving imaging. I've done some In-out tests and the amplitude response appears to be more or less as displayed on the graphs. I've looked at impulse response and there is no pre-ringing, looks like minimum phase. I didn't observe distortion products on some sine wave tests, but this was not done at high precision, so there could be non-linear results at -130 dB that I might have missed.

My next step will be to try some time correction as well, but this is much more complex and I'm not sure what programs are available for testing that aren't expensive.




Tony Lauck

"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar

 

Don't understand your rant, posted on June 5, 2012 at 18:10:40
unclestu
Dealer

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Joined: April 13, 2010
All stereo recordings employ at least two mikes. What's wrong with more and then having to mix them down?

In a live performance, you can't have just two fixed mikes as the solo performer is moving around on stage. It isn't a studio. Concessions must be made to accommodate the performance.

Stu

 

I would add, keep the phase correct. nt, posted on June 12, 2012 at 08:09:37
Norm
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Posts: 30992
Joined: September 6, 2000
a

 

RE: Revisiting Heyser, posted on June 17, 2012 at 11:10:28
middleground
Audiophile

Posts: 22633
Location: Sherbrooke, Quebec
Joined: December 23, 2001
Multi channel sound was attempted on a number of occasions, but simply made too much sense for the world of audio when it turned subjective.

It became more important to overbuild components into absurdity, and to decry all objective standards.

I miss the days of Audio magazine.

Strangely enough, I was contemplating starting a thread asking what people believed were actual advances in audio in the past fifteen or twenty years. I couldn't decide where to start it so as to not get a barrage of "troll" comments.




 

Try, posted on June 27, 2012 at 23:01:08
rp1@surfnetusa.com
Audiophile

Posts: 2751
Location: Norther California
Joined: May 19, 2003
The ReaEq plug in from the Reaper folk. Works at 64 bit precision, and is minimum phase. There is also ReaFIR, a linear-phase para-graphic (meaning you can draw your own curve if you aren't trying to be precise at the moment).

The plugins are free. Reaper has a package for either 64 bit or 32 bit hosts. They are not pretty, but are extremely effective. I have worked with some of the expensive plugins, and always come back to these two.
Give me Ambiguity or give me something else!

 

I miss Dick Heyser: knew him from '79 thru his death..., posted on September 9, 2012 at 01:30:43
Jim Stoneburner
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May 29, 2007
Now that I'm ill, I find myself prompted to reflect on his last year, and his courage and cheer. I can relate and perhaps was inspired more than I suspected. I had poured over his work after, though recollection fades, but memories of the man and the '80s come flooding back.

Your first two paragraphs stunned me, seeming perhaps an old post of mine that I'd forgotten. Physics in '78; acoustics engineer; student and admirer of Dick's work.

I was a colleague at JPL in acoustics and ultrasound, with Dick as a mentor at times, spending hours discussing audio and personal philosophy. After Doug Sax visited us in his office and gave us each LPs including test pressings, Dick gave his pile to me... Per his ethics as Sr. Editor. He tolerated no gray area.

I remember visiting the hospital while he wore a halo, his spine tumor disabling one arm. I believe he was AES Pres or emeritus. At an LA AES he gave his talk by phone. He was my first and perhaps best face-to-face audio influence, along with the Caltech course with James Boyk and a couple of CES shows with JA and Stereophile writers plus manufacturers I was meeting there.

After Dick's death, I helped Gene Pitts by removing some equipment from his widow's house. I even bought the Klipschorns Dick had recently reviewed for a family member. Dick was right - they did sound very realistic from outside the room, even outside the house!

Speaking of Dick's unflappable poise during his illness, I spoke about this with Richard Feynman, an infrequent acquaintance since the late '70s. Richard replied, "oh, that's not me at all... I kick and scream and cry." "Last time they took out 7 pounds. They said they got it all," he added with cynical disappointment. Later, I was comforted to hear that Richard had asked to remain conscious until the very end because, as we all have read of him by now, he wanted to experience everything.

Interesting and learned thread. Apologies for the rambling reflections.



--

Keep your ears honest: Listen to live, unamplified music every week.

 

RE: Revisiting Heyser, posted on September 15, 2012 at 15:24:09
josh358
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February 3, 2012
"He proceeds this with a prophesy, 'Someday we will [have the technology] to record that [the dynamic diffraction pattern of an acoustic performance].'

"It has me wondering, 'Why not?' 34 years later!"

No reason, in principle, anyway. The Kirchhoff-Helmholtz integral says that you can do that with M-S microphones on a surface. A plane array allows you, in essence, to do it for the frontal sound.

In practice, I think we'll first see dry recordings of individual instruments or groups of instruments on separate channels and a position vector. This is just now being commercialized, e.g., by Dolby, and suitable standards already exist. Then this will be convolved with impulse response of the acoustic space and sent to a wave field synthesis array.

The impediments I think have included the large number of channels required -- a problem that is rapidly disappearing -- and cost of the WFS array. I think the WFS array will become economically practical soon enough as well. 1D arrays are already being commercialized. 2D arrays will I think require a heavily integrated approach to keep costs reasonable and so will need the involvement of the large consumer electronics manufacturers. Current off-the-shelf DAC's and amps would be I think too costly for a large 2D array, and that's assuming you had a signal to feed them -- you're going to need to do real-time convolution for all those channels, or have a recording of each channel.

I suspect we'll end up initially with a 2D WFS array in front, and a panned virtual sources approach for the surround.

 

So far as I am concerned, THE brightest light in the last 30 years~nT, posted on September 21, 2012 at 20:15:02
Cleantimestream
Audiophile

Posts: 5865
Location: Kentucky
Joined: June 30, 2005
~!
The Mind has No Firewall~ U.S. Army War College.

 

RE: Revisiting Heyser, posted on September 22, 2012 at 17:44:53
josh358
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I couldn't get the link to work, it just takes me to the home page.

 

RE: I miss Dick Heyser: knew him from '79 thru his death..., posted on September 25, 2012 at 10:35:38
John Atkinson
Reviewer

Posts: 3065
Location: New York
Joined: November 24, 2003
>Now that I'm ill, I find myself prompted to reflect on his last year,
>and his courage and cheer.

Sorry to hear of your illness, Jim.

>I remember visiting the hospital while he wore a halo, his spine tumor
>disabling one arm. I believe he was AES Pres or emeritus. At an LA AES
>he gave his talk by phone. He was my first and perhaps best face-to-face
>audio influence, along with the Caltech course with James Boyk and a
>couple of CES shows with JA and Stereophile writers plus manufacturers I
>was meeting there.

I mentioned Dick's last AES presentation in my Richard Heyser Memorial
Lecture, which I gave at the 22011 AES Convention in New York. You can
download the preprint at the link below (it's a 34MB pdf). I tried to
develop some of the concepts Dick left us with my own experience as a
recording engineer and equipment measurer.

John Atkinson
Editor, Stereophile

 

Lovely to hear from you, John..., posted on September 25, 2012 at 12:05:02
Jim Stoneburner
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And thanks for the PDF. I vaguely recall that you gave this lecture, and am delighted to revisit it now. I very much enjoy the inclusion of your background, expanding on what little I gathered in our conversations, in Santa Fe, Las Vegas, and so on... which I believe started Caltech in James Boyk's classroom and then at the AES conference in LA (not sure which year, but I recall the large screen digital video being shown).

In circumstances like this for me, I find myself reflecting on meaningful influences, the individuals and events that have influenced my development. My appreciation of mentors and inspirations such as Dick Heyser, Richard Feynman, and Chuck Youngberg (a supervisor/mentor at JPL), and others, includes you as well. (They have all long ago died of cancer, and I don't mean to add you to THAT group.) I've always had a special relationship with my image of you ("what I presume to be my cat" - Douglas Adams) based on both our conversations and your writings. Like Dick, I recognize your integrity, authenticity, and honor in a way that many readers might not.

Your PDF gives me something to do this afternoon (while sitting for treatment, using my iPad obtained specifically as an indulgence during recovery). Unlike Dick, my illness is not considered "terminal" but unfortunately "perpetual". Kind of like whack-a-mole based on PET scans every quarter.

Well, time to jump in my loaner car and go to my appointment....I hope to stay in touch now and then....

Best to you,
Jim


--

Keep your ears honest: Listen to live, unamplified music every week.

 

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