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In Reply to: RE: How to reproduce the full dynamics of a scissor cutting paper without clipping posted by tomservo on April 18, 2017 at 09:55:36
"I am afraid your confusing two different things,"
Actually, no. Obviously, the sound level picked up by a microphone will depend on the distance from the sound source. Scissors cutting a piece of paper is a very small sound - even with its peak level - at a more or less "normal" listening distance, to the point that, if there is conversation or other sounds in the room, it's practically inaudible and definitely ignorable. Take your B&K sound level meter, put it a meter or two from scissors cutting paper, and in an average home with average activity, it'll barely show up on the meter. Certainly, nothing like 140 dB peaks! Holy moly, we'd all be deaf by now, just from cutting paper in grade school!
(BTW, I remember those humongous B&K sound level meters! They were very cool - and precision!) and had WAAY more buttons than I needed!
If you place a microphone very close to the source (scissors cutting paper), then we can hear all kinds of detail which is typically lost in a normal setting and distance, and the average-to-peak ratio becomes quite apparent, especially when one views the waveform on a screen using something like SoundForge or ProTools. Last year, just for the fun of it, I recorded a triangle (you know, like they use in the percussion section of a concert band) at various bit rates/depths. I seriously had to put the mic within about two feet just to minimize the ambient sounds.
So, if we record the sound at a very close distance (inches away), and try to play it back at a fairly loud level, where the listener is NOT at a very close or normal distance, then that's a whole different ballgame.
I think I still have the recording of putting a key into a door lock. I still remember Josie B. (violinist) coming down the hallway and saying "Hi", then, realizing that I was recording - softly saying "oh, I'm sorry". Hahahaha!
No, you do not understand.
As opposed to measured SPL, Subjective loudness is not only level dependent but also frequency dependent (as the equal loudness curves show) and relevant to this discussion also Time dependent where short sounds are not perceived as loud as the SAME ACTUAL SPL for a longer duration.
In the examples I gave, I WAS holding the meter and my ears were approximately the same distance away from the source, those levels were the instantaneous peak values and even if it had been set to "Fast", the meter would never have reached anywhere near that value.
Maybe this will be clearer. Microphones have a pressure sensitivity figure, if you measure the voltage coming out of one, one can calculate the pressure that caused that Voltage. Vu meters, SPL meters (generally) do this conversion and give a display but these have significant integration times, more like our ears.
If one examines the microphone voltage with an oscilloscope, one can capture the peak voltage any event produces and these peak pressures for many sounds are far greater than the average level over say a fraction of a second or longer.
Now, I have never measured a key in a lock or scissors but a reoccurring them with household sounds and percussive instruments was that the peak levels were often surprisingly high compared to what a normal "fast" SPL meter showed.
The best part, you don't have to take my word for it, anyone with some modest testing ability can make the same kind of tests and see for themselves what sounds are really like, what is really required and not just the part that is convenient to reproduce that at best only reminds you of a real event..
Possibly the biggest thief of subjective dynamic range (aside from the recording end) is instantaneous clipping which unlike prolonged clipping is inaudible as a flaw and only apparent when you compare with and without it. Here too an oscilloscope looking at your power amplifier output (fast triggered sweep) will show if there is clipping at any stage up to there.
That's an interesting concept, and something that Richard Heyser was interested in, which related to the paradoxes between the quantum domain and our macro world. As you come arbitrarily more precise in one domain, for instance the peak voltage measured by a test microphone, you also become less precise in the average level of an acoustic event in the time domain, at least as far as this relates to the to the "big picture" of our subjective hearing perception. So a car door slamming inside a car can be 140 dB peak, but the time averaged level of a jet aircraft taking off at several hundred feet distance can also be 140 dB.
Back in the 70's recording engineers had to get used to the then-new peak reading VU meters on some stuff, as opposed to the old school ballistics of the more averaging old school VU meters. It was well known that a violin section for instance could be pushed into the red with peaks on the VU meter, but you had to be much more conservative with a close mic'd drum kit for another instance as the peak dynamics could go right past the standard VU meter. The peak reading meters allowed for less leeway by the engineer, but this paved the way for the forthcoming CD digital age in recording where overload had to be avoided at all costs.
And, what you're telling us "new" is that you've figured that out?
Good on you!
"forthcoming CD digital age in recording where overload had to be avoided at all costs." ------ Paul Eizik
Or the terminally stupid "loudness wars" where the dynamic range is compressed to only a 1 db variation at minus 1/2 db from "all bits on.'
That's another can of worms which has been discussed here before. While audiophiles who believe in an "absolute sound" have been trying to put more dynamic range into recordings by promoting speakers with a tonal balance noted by J. Gordon Holt as having a tilt towards the bass plus a treble peak, there were others in the popular music end going the other way by cramming in more average energy into the recording. Back in the days when the distortion wars were in full swing in the 80's, transistor amps appeared with THD figures into three digits below the decimal, and they were touted as having distortion so low it was beyond the ability of human hearing to detect it. At the same time the Japanese were building SET amps which had much higher THD but some said sounded subjectively more like real music, but you really had to have horns to get the most out of them.
"...there's always a counter force": Thomas Pynchon
A quick visit to a garage band with live drums should tell you all you need to know about the reproduction of live dynamics. Since the Blue Ray format easily accommodates 130 db dynamics (but very few, except AIX) seem to use it, having speakers like Klipsch Jubilees or Danley Synergy Horns should tell you all you need to know about REPRODUCING those dynamics.
Even though they do "sound good." Those overprice little direct radiator speakers are not designed to emulate live music. But then again, they don't have to for that application.
Owning horns is like having a 200 MPH+ car with 6 gears. You may never take them out of 3rd gear on normal roads, but it's nice to have the option to open them up on a race track once in a while.
Guys with direct radiators don't have that option.
Don't attempt to talk down to me and others. Not all of us are audio morons. I'm listed as "audiophile" here mostly because I'm not currently a "manufacturer" or "industry professional", but I could get back into the biz if I wanted to. These days, I just do it for fun.
Loudness, frequency, perceived loudness, pitch? Duh. I learned that stuff in the early '70s.
As a musician (trumpet) and recording engineer, I totally "get" the whole waveform and peak thingy.
You don't need to yap at me about waveforms on an oscilloscope.
Sorry I didn't imply you were a moron I was trying to be clear.
I wasn't aware of your background (and still don't know) as it seemed like you had no idea what I was talking about and perhaps you didn't because this area of research was more like the 80's and 90's.
Like I said, the reality is there for anyone who is curious enough to look and it doesn't take much test equipment to do it and see what I am talking about.
You specifically stated:
"No, you do not understand."
On the contrary, I DO understand.
yes i did and that was in response to you saying something demonstrating you didn't understand the implications of how things work or what is actually required to reproduce common sounds.
Like i said, the sound level meter was in my hand, not close to the spoon or car door, those are the levels i heard but didn't judge to be "that loud" because a peak hold meter measures the sound pressure, we / our hearing system judges loudness.
Hate to have to post this, Tom. We can all see who's in the "ASShat chair" and it 'aint you. So don't respond to this troll.
Thanks Claude but when you say something another finds unbelievable but is sincere it's worth trying to explain a bit further.
Back in the 80's when the Servodrive subwoofer was born, imagine how hard it was to convince anyone that you could produce low and loud bass with a motor, now that was a challenge haha
Doing things "a different way" as opposed to parroting convention always requires explanation.
Data never lies, and you certainly have provided more of your share of that stuff!!
Really Who cares?! this system is abomination spliced together with Digital correction!, Yeah it will prob play very loud and IMO because its a horn system you would need to be across the street to hear it gel like normal folks systems wow
Your points are well taken in general horns donīt Gel immediately but in Danleyīs (tomservo) Unity type horns you can actually stick your head inside and will be unable to discern the mix of the different components. Mr Burwen system likely has the same effect. Remember this system has 50 years of a learning curve with a brilliant audio consultant working on it. By the way I have never met or had any business relations with Mr Burwen but do appreciate his work.
Hello Inmate 51: In reply to your edited non published versions
In regards to being a fan (boy) of Tom Danley I am guilty. Tom is an exceptional and kindly person a brilliant designer, inventor and a true acoustic scientist. I hold his designs in the highest regard. Additionally he takes the time to patiently pass his extensive knowledge to others as he tried to pass it on to you. I personally have learned a lot from him you would well to keep an open mind and do the same. Nobody knows everything we are all here to learn,share and enjoy. Best
Your comments are accurate about Tom sharing his knowledge openly on all these forums. He's the same way in person.
Plain text on the internet forums can run the gamut from industry giants to audio newbies. With and without egotistical personalities attached.
When I have to choose whose contribution is more valuable here, professionally speaking and with personal benefits attached, I'd rather trust someone who has designed and sold about 70 unique speakers and subwoofers over the last 15 years (many of which I own or have heard myself), with 63 of the in CURRENT production, rather than someone that claims to have done something in the past and nothing current except words.
As in the world of photography, Ansel Adams really knew how to "hang em on the wall"
In Toms case, he really knows how to make large spaces sound as good as high end hi fi in your living room. That is quite a feat in itself.
Tom has been a mentor to me indirectly from his patents and publishings and also from the occasional direct helpful contact. As an amateur speaker designer he helped me accomplish my goals but perhaps the most important thing I learned from him was this
Danley Mission Statement: To find favor and a good name in the sight of God and man. Proverbs 3:4 (This from the 2009 Danley Products Brochure donīt see it anymore in the present brochure)
Very impressive statement when the person behind it really lives up to it as he has throughout the years. I can be an intolerant aggressive prick but have learned to mellow and guide others as he has with objective patience and understanding. This perhaps has been my greatest accomplishment!!
And you are correct about Ansel Adams...had his Black and White book of fotos.
I seriously gotta post a pic.
Looks like a good idea. As a professional photographer, I do believe a picture is worth more than words (although most photographs don't merit the full 1,000 either).
There's an old saying "In God we trust, all others provide data." LOL.
I don't know what the problem is with that post. Try as I did, it doesn't show up correctly on my 'puter. Here is more-or-less what I intended:
"Your points are well taken in general horns don
OJK, it still doesn't show up correctly. Maybe there's a goofball character which is screwing it up.
Anyway, part of what I wrote was that I think Tom has a good horn design idea. I just don't think he knows everything or is a god of loudspeaker design, and it's irritating that he says I don't know what I'm talking about. As a musician and recording engineer (read my profile), that's a big slap in the face.
Regardless, based on the words you posted, it would seem you have a fragile ego and have a huge tendency to over react negatively and insultingly to anyone's perceived verbal shortcomings while trying to make their point more clear to everyone here.
Yes the message posting seems to be going crazy. I read Tomīs postings to you. He is a teacher by nature and was just making sure you got the meaning of what he was saying. Think of all the effort and time he took to pass that info to you. How may people would care or even try. I have never in more than 10 years of posting seen him insult or treat somebody as ignorant or inferior!
Today itīs still not widely known about the "silent unheard" instantaneous short term peak in the dynamics of sound events. It certainly was not tought in Sound Engineering when I was there. Mr Burwen was way ahead of his times trying to reproduce this in the 70s. Only in the late 80s and 90s was it really talked about a little. Like Tom pointed out our hearing is not linear but varies in sensitivity with volume, freq and time and will not "hear" those "instantaneous" dynamic peaks yet recordings will be "perceived" to be more realistic when the equipment can reproduce them. Just something to keep in mind especially in Sound Engineering. Best
"Today itīs still not widely known about the "silent unheard" instantaneous short term peak in the dynamics of sound events"
That's is probably true for live or live mic feeds but with recorded music it's easy to know where they are and it's easy to see them.
In the age of digital recording and CDs, we know that the highest peaks are all contained within peak output of the CD player.
If a system has a gain structure such that clipping cannot be reached even when the CD player is outputing it's max (recorded signal at digital "0") and the volume control is turned all the way up, then we know for sure that those "instantaneous short term peaks" are being reproduced without the amplifier clipping.
Have Fun and Enjoy the Music
"Still Working the Problem"
"Your points are well taken in general horns donīt Gel immediately but in Danleyīs (tomservo) Unity type horns you can actually"
Ah, now we're getting somewhere: You're a tomservo fanboy.
"don't Gel immediately?" What does that even mean?
Read this closely: I think Tom Danley has a great horn design idea. I just don't think he knows everything or is the god of loudspeaker design.
(Edit: This is edited because it was somehow truncated when I originally posted it.)
It is not hard to pick the obsessives on this forum.
Before recovering from Audiophila Nerviosa my Home theater consisted of five Altec A5 cabs, 8-15" woofers in infinitive baffle in the attic, Tons of amps etc. The cure was the Bitch took everything in the divorce. Jajaja
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