The sound reaches each ear after quite a variety of acoustic influences. The factors that lead to a judgment of loudness across the freq compass are variously influenced by these factors and not in any well-understood way, even if many people would agree on the loudness of frequencies, either as test signals or with music playing, in the same room.
Test tones and mic traces meant to capture the stimuli at the ears can't do much justice in assessing the human response in this complex situation. Makes me think of Godel's Theorem. Therefore, there is general agreement that it is just accidental when some concept of mic measurement results in system settings that seem right on music.
Is there the same kind of dispute about headphone flatness, say with an Etymotic in-the-ear kind of headphone? In this case, the stimuli do not have much influence like the way music in a room has.
What I'm saying is, we are far from having a system of measurement which can do a good job in setting relative loudness across the freq band. (And that's without considering the Fletcher-Munson issues.)
Test tones and mic traces meant to capture the stimuli at the ears can't do much justice in assessing the human response in this complex situation. Makes me think of Godel's Theorem. Therefore, there is general agreement that it is just accidental when some concept of mic measurement results in system settings that seem right on music.
Is there the same kind of dispute about headphone flatness, say with an Etymotic in-the-ear kind of headphone? In this case, the stimuli do not have much influence like the way music in a room has.
What I'm saying is, we are far from having a system of measurement which can do a good job in setting relative loudness across the freq band. (And that's without considering the Fletcher-Munson issues.)
Hello Ben
General agreement? Among who?? I would quess that many here who have used measurements to purposely set-up their systems would disagree. They would argue that without the measurements to help point them in the right direction it would have taken much longer through trial and error.
I disagree with that. I can set-up my system very quickly using measurements and get good sound with repeatable results using different speaker systems in the same room.
I assume you mean octave to octave balance and and overall curve being flat, tilted or otherwise?
Rob
Do people have the same issue with headphones? Do they want to tweak an Etymotic or do they accept that as the very definition of flat?
Headphones need to build in an approximation of the head and outer ear transfer function to "sound flat". This includes a hefty boost around 2700 Hz. If you measure the frequency response, good headphones are far from flat. The brain calibrates its perception of "flat" to the frequency response received through the attached ears. Now, my ears may be differently shaped from your ears, so the one-size-fits-all-ears approximation in a pair of headphones may "sound flat" to you, but not to me, or the other way around.
BTW: I love my Etymotic ER4's "tweaked" with custom earplugs in molded silicon.
Etymotic Research, Inc. - ER-4 MicroPro Series
BTW: I love my Etymotic ER4's "tweaked" with custom earplugs in molded silicon.
An externally hosted image should be here but it was not working when we last tested it.
Etymotic Research, Inc. - ER-4 MicroPro Series
Let me restate some of that in what I believe to be more correct (and perhaps more helpful) terminology and offer something (which I now finally realize) is a premise to this discussion.
It is immaterial how the headphones deliver sound you perceive to be flat. They use an EQ to correct for ear and head considerations unique to that delivery system which works for most people or a custom correction for special people.
The brain isn't correcting for anything - the headphones are. In the ear drivers have a different EQ than circumaural ones and different from loudspeakers. I suppose you could say the loudspeakers are correcting for the room and for themselves. But it is also true they are correcting for being a front-stereo delivery system. So a HT 5.1 system would need different correction.
Because heads differ a bit, the Etymotic EQ and/or ear mold has to differ a bit to deliver sound perceived to be flat, at least for cases where the head is atypical. And roughly the same thing is true of rooms; you need to correct loudspeakers differently for each room since none are typical.
Premise: the goal is to deliver sound perceived to be flat. I don't think there can be any other point of view or at least, none that leads to any coherent analysis. The view that "it is a matter of personal taste" might be considered like soup: you can say you like your soup salty and I can say I like it unsalty. But we can agree, roughly, on how the soup in question compares to a "standard soup" in a comparison bowl. Sometimes you get served soup that is too salty and sometimes you get served recordings that are too bassy.
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OK. Still not sure what you're driving at.
Thanks for taking posts seriously enough to ask.
I am wrestling - thinking out loud with collective wisdom here - about why there is substantial agreement that when you've done your darndest with a mic, you still need to tweak the EQ to have music sound right. That is very puzzling, at least to me.
From that observation, and given the premise that there does exist an objective criterion called "flat," it is fair to conclude that the essential problem is that there is no system of measurement which seems to characterize the heard-experience satisfactorily for enough people and places. I am optimistic.*
Toole feels he has a way of characterizing speakers well enough to predict their room behavior pretty well. But it is a vast set of anechoic measurements.
*Don't forget, we are talking only about getting the freq compass flat. Which ought to be simple. Getting a front-stereo loudspeaker set to reproduce other parameters of Carnegie Hall is all but hopeless.
you should read up on the jerry harvey audio jh3a custom in ear monitor system. it is due after a long delay to be released very shortly. i have the version of this custom fit monitor with the inbuilt passive crossover and 6 drivers per ear. there is a new version that removes the xo from the monitor and places it inside a portable digital 6 channel amp and crossover (along with multiple conductor cable); each set is adjusted to what is called 'ear flat' taking into account the response of the portion of ear canal tat is not filled with the monitor, by use of a dummy head and the actual monitors plus tuning the dsp. very interesting; especially if you know what the passive version already sounds like
just saw the last post. do remember there is such a thing as personal subjective experience and taste; of course there will be some adjustments needed. otherwise we would all agree on a system of speakers that becomes the standard and all have those adjusted flat to our listening rooms so they sound the same. that will simply never happen, even the jh3a i mention above has the ability to be updated and has a bass dial (which also allows you to take it away) dependig on what instrument you play. jhaudio supplies custom iems to a large ampount of onstage musicians we see every day and invented the system for the other 2 major dominating brands
just saw the last post. do remember there is such a thing as personal subjective experience and taste; of course there will be some adjustments needed. otherwise we would all agree on a system of speakers that becomes the standard and all have those adjusted flat to our listening rooms so they sound the same. that will simply never happen, even the jh3a i mention above has the ability to be updated and has a bass dial (which also allows you to take it away) dependig on what instrument you play. jhaudio supplies custom iems to a large ampount of onstage musicians we see every day and invented the system for the other 2 major dominating brands
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Ah, got you. Yes, it puzzled the hell out of me, too - until I came to realize we are using the wrong microphones.
It's mostly about power response. We and the mic hear the entire room, not just the direct sound. But the human ear is not omni-directional. Not at all. In fact it's much closer to a super-cardioid pattern. That's 1/2 way between the normal cardioid mic and a shotgun mic. The Schoeps MK41 is a shining example of this - and the mic I'd use, if I could afford it. (about $1K)
Having done a good bit of recording since I was a kid (dad's R2R) the fact that the mic picks up so much more "room tone" than we hear was always puzzling to me. Try a recording of your room thru your measurement mic. Record a speaker or two, record someone's voice. Sound right to you? Unless you have a very dead room, I'll bet it doesn't. I'll wager it sounds much too live and tonal balance is off. It's interesting to note that the MK41 has a reputation of making recordings that "sound like the venue."
An omni mic just does not pick up the room the way your ears do. It picks up a disproportionate amount of reflection from behind your head.
Of course it's never so simple. We have two ears (most of us) and a head between them. We are not set up like an omni-directional microphone at all. We don't hear the room the way the mic does. Maybe we should be measuring our rooms with dummy heads - and a calibration file to compensate. The dummy is going to hear the room a lot more like we do, more so than the omni mic. The omni mic is great in an anechoic chamber where there are no reflections to pick up. Not so great in a small to medium size listening room.
Caveat: Most people disagree with me on this. They are stuck with the omni-directional mic because it's "flat." I use an omni mic, but take its reading with a grain of salt. It does not hear like I do.
It is at least in part, I think, because the mic is such a non-discriminating tool. It has no analytic capacity, no ability to discriminate source direction, and with the measuring tools usually associated it does not offer much time discrimination either. Our ears, and the highly-specialized-to-other-purpose-than-listening-to-music processor between our ears does a lot more . . . distinguishing source from reflection, subtracting familiar (anticipated) room effects, comparing the subtly different sound at receptors separated by a diffracting object . . . it should be no surprise that we "hear" something more complex than a line drawn by a mic and simple amplitude-summing processor, since that's a very blunt instrument for addressing a quite complex set of acoustic inputs.
Pano, in a few weeks I'll get back to you--you're sort of talking about what I am sort of working on.
Ben, what I've noticed is that I generally don't feel the need to tweak anymore. I've just concluded that the recording is the biggest issues when listening through headphones even though I don't have any that are perceived flat. My SE110 are probably the closest minus a little air. I do leave my EQ elevated 6dB in the top octave and it generally sounds as nice as I've ever heard headphones. If I had a better EQ, I'd do more tweaking without a doubt. My 840 sound darn good as well if a touch heavy in the bass. I just leave them be anymore.
Dan
Ben, what I've noticed is that I generally don't feel the need to tweak anymore. I've just concluded that the recording is the biggest issues when listening through headphones even though I don't have any that are perceived flat. My SE110 are probably the closest minus a little air. I do leave my EQ elevated 6dB in the top octave and it generally sounds as nice as I've ever heard headphones. If I had a better EQ, I'd do more tweaking without a doubt. My 840 sound darn good as well if a touch heavy in the bass. I just leave them be anymore.
Dan
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We are talking only about the simplest aspect of reproduction: frequency x loudness.
Considering the thoughts of the previous posts.
Cardioid or whatever, there will always be some mic measurement that sometimes will result in a satisfactory result in some rooms. People (esp. on this website) will then argue about the CORRECT angle for the mic pick-up pattern (the interminable "directivity index" thread).
Maybe pursuing Pano's line of thought would be productive. But I think the goal would still be elusive without somehow moving time-waterfall analysis from "eyeball demo" to numeric.
Arguments about directivity (and the mirror-image question of mic pattern) might be viewed as veiled attempts at capturing time-course parameters. To the extent that a speaker has a cannily chosen DI, it might work nicely in certain rooms without EQ tweaking (although not in all rooms). Likewise for Pano's mic testing.
I guess I am coming to another premise: in reverberant room, you have to take the time course of sound into account in predicting loudness (and in a manner which possibly isn't simply adding together inputs reaching the ears).
Considering the thoughts of the previous posts.
Cardioid or whatever, there will always be some mic measurement that sometimes will result in a satisfactory result in some rooms. People (esp. on this website) will then argue about the CORRECT angle for the mic pick-up pattern (the interminable "directivity index" thread).
Maybe pursuing Pano's line of thought would be productive. But I think the goal would still be elusive without somehow moving time-waterfall analysis from "eyeball demo" to numeric.
Arguments about directivity (and the mirror-image question of mic pattern) might be viewed as veiled attempts at capturing time-course parameters. To the extent that a speaker has a cannily chosen DI, it might work nicely in certain rooms without EQ tweaking (although not in all rooms). Likewise for Pano's mic testing.
I guess I am coming to another premise: in reverberant room, you have to take the time course of sound into account in predicting loudness (and in a manner which possibly isn't simply adding together inputs reaching the ears).
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Yes, ultimately reflections do add to perceived frequency balance--Dr. Toole says "timbre" if I remember correctly. The degree of which is hard to quantify--at least to me. How much do we adapt to the room is another thing. SL want's to hear the room reflections. Toole's experiment with the different rooms and the dummy head recording is interesting--the speaker having say while listening in the room, the room being dominant while listening to the dummy head recording.
The big thing I want to see in person is how is the frequency and time domain differ from a single omni and a dummy head. Maybe it will prove interesting.
Dan
The big thing I want to see in person is how is the frequency and time domain differ from a single omni and a dummy head. Maybe it will prove interesting.
Dan
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The riddle hidden in there is that we are talking about different, non-combinable domains - loudness and time. Yet they interact to produce perceived loudness. If they didn't interact (or if they could be combined in the simple math combining torque, horsepower, g-force, etc.), it would be a simple matter to measure loudness with a mic or two and be spot-on for hearing.
Toole's basic goal is to produce satisfaction and so he gets into this weird religious war with "others" about ambiance and the role of directivity which results in nice ambiance. I think it simplifies things to aim low, just trying to get the measurement of frequency loudness right.
Toole's basic goal is to produce satisfaction and so he gets into this weird religious war with "others" about ambiance and the role of directivity which results in nice ambiance. I think it simplifies things to aim low, just trying to get the measurement of frequency loudness right.
You won't get any argument form me on that account! But I don't know the details. I can say for sure that even very late reflections can have a big influence on the perceived tonal balance. Setting up a P.A. in a hockey rink, aircraft hanger, warehouse, ballroom, etc., will teach you that fast.
For me, getting the polar response of the measurement right is the first, and a very important, step. Somewhere on these pages is mention of frequency weighting by time. Maybe someone remembers? How is the reflected sound altering the tonal balance, and what are the windows wherein it becomes separate form the direct sound?
Not by me. And at any rate science is not a democracy so "consensus" doesn't mean much.
As to headphones, the Etymotic claim of in-ear "nuetral" is quite contentious. It is based on a free field measurement of the sound field on a Kemar, but most importantly it is in steady state, i.e. the revberberant field. There is much dispute as to the correct in-ear measurements for a more direct sound field as opposed to a reverberant sound field. Experts like Ultimate Ears (UE) do not use anywhere near as much peak gain as Etymotic for just this reason. Shure tends to floow UE in this regard. For my taste the Etymotic earphones are far inferior to any of the UE or Shure devices.
Please share with us your method of measuring rooms in setting up systems that inevitably leads to never needing to tweak afterward?
Funny, my impression has always been that excepting aboriginal whaling crews, few human activities are as social and cooperative as science. True, some spell "truth" leading with an uppercase "t" and thinking of science in terms perhaps more akin to your understanding, if I correctly grasp the alternative to "consensus."
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