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In Reply to: RE: Ideal frequency response curve posted by Todd Krieger on June 16, 2015 at 12:59:54
A friend who has designed speakers commercially told me that flat response sounds bright. The solution is a 'flat' curve that slopes down ever so slightly with increasing frequency.
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If I recall correctly the reason for the slight response decline was that the power response of a flat speaker made the speaker sound bright.
I think part of it has to do with trying to get true full-range sound with speakers whose boxes and/or drivers are undersized. The excessive excursions of smaller bass drivers often result in both harmonic and Doppler distortion, which does add amusical components to the upper end of the audible range.....
With larger boxes and drivers, the bass is linear, allowing the harmonics of all instruments to be heard in a more natural state. I've found that lack of bass linearity causes the "brightness" that is too often blamed on extended HF or flat FR.
I've even noticed the impact of bass linearity on the top octave.... IMO, high-frequency clarity is almost a lost art in sound reproduction. Hearing the sweet "sparkle" of the triangle in the midst of full orchestral forces often brings goosebumps inside a concert hall, but is one of the most-difficult things to capture and get right in home audio.
The reason why a rolled off response sounds best is that recordings are made to sound good in the mastering studio on the mastering studio's speakers. Most of these have high frequency roll-off. Therefore a recording played back on an audiophile system with flat response will sound brighter than the way the mastering engineer heard it, that is to say it will be too bright (assuming the mastering engineer did a good job making the recording).
The question then arises: why does the mastering engineer have a speaker that is rolled off? The answer is that the mastering engineer wants his recordings to sound good on a variety of playback systems. These range all over the place, so it is a bit of a crap shoot. However, if his recordings fall near the center of the rolled-off vs. too-bright distribution of recordings then he will have the best chance of his recordings sounding good on many systems. The historical fact is that most recordings sound best when played back on systems that have slightly rolled off high frequencies. Therefore it is helpful to the mastering engineer if his playback system is slightly rolled off. When setting up his mastering studio, a first rate mastering engineer will dial in the high frequency response of his monitors by listening to a wide range of recordings and picking a reference set used to set up his monitors.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
"The question then arises: why does the mastering engineer have a speaker that is rolled off?"My answer is that the digitization of audio has essentially forced such practice.... Prior to the digital age, extended HF (beyond the audible range) was often highly desired, some even claiming it enhances how we perceive the sound within the audible range.... (Even Radio Shack was marketing ribbon tweeters and other extended HF products in those days.)
This totally changed when the bandwidth limited CD displaced vinyl as the consumer medium of choice. (And with MP3 dominating current music sales, the need for extended HF seems to have gone away completely.)
With the comeback of vinyl, if future digital electronics (computers, entertainment products, etc.) can tame the RFI emissions which I think brought down quality sound reproduction at all levels, we might have a resurgence of audio products with extended HF. Not to mention maybe even studio products that do likewise.
"The answer is that the mastering engineer wants his recordings to sound good on a variety of playback systems."
I don't think using rolled-off speakers would be an ideal conduit to make recordings sound good on a variety of playback systems. Even playback systems of the Best Buy variety.... If one doesn't know what's up there, how would he know if it will sound OK on other systems?
Maybe this is why we've had recordings with strange HF artifacts in recent time. If the drivers are excessively rolled off, and the mastering engineer doesn't hear the top octave, he might not be aware of HF artifacts that could make it to the final released product.
The mastering engineer should be able to hear everything, good, bad, and ugly. He would then be able to better determine what would be best for a variety of systems.
Edits: 06/17/15
In my original post, I provided a link to Bob Katz's book. It has a whole chapter on how to set up a mastering studio which goes into the question of high frequency roll off in the monitoring.
This has nothing to do with the high frequency response of digital vs. tape recorders or vinyl. This has to do with rooms, microphones, speakers, acoustics, and psycho-acoustics. All the same issues of frequency response, too bright recordings, etc. existed back in the early 1960's when I was listening to pre-recorded stereo tapes and mono LPs.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
"The reason why a rolled off response sounds best is that recordings are made to sound good in the mastering studio on the mastering studio's speakers. Most of these have high frequency roll-off. Therefore a recording played back on an audiophile system with flat response will sound brighter than the way the mastering engineer heard it, that is to say it will be too bright (assuming the mastering engineer did a good job making the recording)."
Tony, you seem to be a bright guy, but you, along with others, are on the wrong track here.
The question is not about speaker FR curve, but rather about ROOMS and how we perceive the sound in them. A rolled off upper frequency curve is preferable - FOR THE ROOM SOUND - which is what the OP asked about.
:)
I was talking about frequency response of speakers in rooms at the listening position . Speakers are designed to be used in rooms and their frequency response outside of a room is irrelevant to an audiophile or recording engineer (although not to a speaker designer). The in room response of a speaker will vary according to its position in the room as well as the listener's position in the room.
This does not describe why frequency response in the listener's room at the listening position needs to be rolled off. This depends on understanding how recordings are produced.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
| This does not describe why frequency response in the listener's room at the listening position needs to be rolled off. This depends on understanding how recordings are produced.
Specifically, why do you think the frequency response needs to be rolled off? What's important mechanism, and what isn't?
How much validated by experiments?
This isn't a rhetorical question. I think we all now agree on the phenomeon but I want to know other than "it sounds better", why? What part of measurement and playback which, at least superficially seems to say that we have reproduced the same thing, doesn't actually reproduce the psychoacoustic same perception?
Presumably if we cloned everything about the original and transplanted a new human into that recreation, like an acoustic holodeck, then some version of "flat reproduction" should be correct.
My record library consists almost exclusively of recordings of acoustic music, a mixture of studio recordings and recordings made in concert halls with or without an audience. If I play these recordings on a system set up for flat high frequency response (as measured at my listening position) these recordings are heavily skewed to the bright side. Some highly regarded recordings, such as most of the Mercury Living Presence recordings, are so bright that they are painful to listen to, the equivalent of "fingernails on the blackboard". None of the recordings in my library sound dull with my system set up flat. When I adjust the high frequency response of this system so that the recordings range from slightly dull to slightly bright, nearly all of the recordings in my library sound very good, and the ones in the middle sound excellent. None are painfully bright and none are boringly dull.
I know what live music sounds like from decades of going to live concerts. I know which recordings in my library are the best from reading reviews and years of experience listening to many of these on different systems. I know that, as originally set up with "flat" cross-over settings, my system was horribly bright. I measured it's response at my listening position and it was flat from 1 kHz up to 20 kHz, which was as high as my calibrated microphone went.
After adjusting the high frequency response (by turning the high frequency control for the tweeters on my left and right speakers half-way down) I got a setting that sounded approximately correct, consistent with live music and consistent with how these recordings sounded on other systems. I measured this and found that there was a gradual roll-off starting around 1 kHz and ending up down -3.5 dB at 10 kHz, leveling out at a maximum attenuation of about -4 dB at 12 kHz and up.
I already explained why recordings tend to be too bright on flat systems. That's because that's the way they are made. If you want to know why they are made that way, you would have to talk to the people who made these recordings (most of the great engineers are no longer with us). While you are at it, you can also talk to the successful speaker designers, who won't sell many recordings if their products were flat because customers don't buy products that give them "bleeding ears".
Anyone who wishes to confirm this for himself will need to meet a few requirements:
1. They must have a system that is full range for the music being played.
2. They must have the ability to accurately measure their system response at the listening position using calibrated instruments.
3. They must have a record library with a wide range of acoustic music
4. They must be intimately familiar with how live music sounds by attending numerous concerts of different types of ensembles in different halls from a variety of listening positions in the venues.
5. They must have the ability to compare their memory of live events with what they hear when they play recordings of similar ensembles on their system.
6. They must have some way to adjust the frequency response of their system, at least as flexible as traditional tone controls.
7. They must have the ability to listen critically and identify small differences in frequency response while listening to music, down to at least the +- 0.5 dB range over 1/3 octave bands.
None of these requirements should be difficult for a competent audiophile.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
"customers don't buy products that give them "bleeding ears"
Very thoughtful response, Tony. Nice contribution.
But I'm not sure manufacturers don't mind adding a little sizzle to their steak. It's called "detail." I hit the CES and Rocky Mountain audio shows every year, and too many times I don't make it more than three feet into the demo room before I rush right out again. OW! OW! OW!
Perhaps its because there is no blood left in the ears of the younger generations as a result of attending a few rock concerts or from having headphones permanently welded to their skulls. Or maybe they figure that the real buyers of their stuff are old guys (like me? us?) who need a bit of boost in the high freqs or we can't hear them at all. But that's all just speculation.
I haven't destroyed my hearing by abusing it. When I was 19 I could hear 21 kHz. Today, at 71, I can still hear 13000 kHz. Live music doesn't sound dull, and I can hear tonal differences in music when cutting or boosting frequencies above 15 kHz, even though I can't hear sine waves at these frequencies any more. The mind provides needed recalibration of frequency response providing that one's hearing changes gradually. If there is sudden damage due to accident or illness then this may not happen.
I have no use for equipment that is marketed to people who listen to non-acoustic music. The existence of these people and the existence of this music is one of the reasons why there has been little real progress in audio over the years. If I were appointed "Musical Dictator of the Univers" my first edit would be the banning of all musical instruments that are not operated on human power. (This would even include banning pipe organs, unless they were hand pumped.) :-)
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
After your ban on non-acoustical instruments becomes effective, what will we do with all of those people who once liked them?
Oh man, my head hurts. Put yourself (speaking to no one in particular, mostly all you cats that are so well read in this stuff) in my shoes, just a regular joe who enjoys hi-fi/stereo/music & equipment. Now I'm trying to grasp a little of what this thread is saying & how it applies to me or my listening & understanding music. After 3 or 4 posts, I felt as lost as I would be listening to Einstein explaining the relativity deal. My head has shut down. So maybe I'll just go enjoy some music & let you guys debate whatever it was this started with. ** BTW, I'm not being flip, I honestly admire all you who understand this stuff. I just accept that I ain't gettin' it. Carry on men, Dave
Everyone thinks I'm strange except my friends deep inside the earth
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