This may be a good place to start for what ails us:
http://www.bobgolds.com/Mode/RoomModes.htm
To EQ the frequency domain to attempt to solve a time domain issue is still and always will be adding problem on problem..............I haven't touched my EQ in many months and I listen to just about everything and movies too. All the oddiophile buzzwords are represented and I've only EQed the bass.
Dan
Dan, sometimes you have to EQ frequency before you can even know what to think about what's going on in the time domain.
Not all rooms present the same problems - or, at least, the same parameters in the same proportions.
Anybody heard one of those Met (opera) movie-theater broadcasts to the hinterland?
No, but my mother goes frequently. I need to go to one. It will be interesting to listen with eyes closed. I don't expect it to be brilliant, but it probably won't be bad, either. Will it sound like a reasonable facsimile of being at the opera? That's what I want to know.*
Getting something that sounds like what you expect in the concert hall is a fine goal, it's one of mine. But since I don't sit where the mics are, and there is at least some tweaking done to the signal, just how do you get there? Having heard recordings of events that I've attended live, I don't remember one that really matched. But I have been fooled into "wow! that sounds right!" on some occasions where I did not hear the actual performance. Getting more of those moments is a personal goal. That's all I really expect.
*Marcel Proust used to listen to the opera via telephone. It was a service available in Paris at the time.
When you go to the symphony, you usually hear the tiny sound of the triangle pretty clearly whatever other racket is going on. That's because we "aim" our hearing at it (or it grabs our hearing).snip
Getting something that sounds like what you expect in the concert hall is a fine goal, it's one of mine. But since I don't sit where the mics are, and there is at least some tweaking done to the signal, just how do you get there? Having heard recordings of events that I've attended live, I don't remember one that really matched. But I have been fooled into "wow! that sounds right!" on some occasions where I did not hear the actual performance. Getting more of those moments is a personal goal. That's all I really expect.
A great recording of a symphony has the triangle mic cranked up during triangle parts a lot so that we - again - have the triangle grab our hearing and the recording captures the composer's intentions.
That leads to two opposite views of "reality".
1. Cranking up the mic just ain't reality because you are tweaking the sound waves.
2. Cranking up the mic makes the experience of listening to music at home truer to the concert hall experience (we in the trade might say the "phenomenological" experience is closer). That is because you are able to attend to the triangle in the concert hall but require some help doing so from a recording playing in your little room with correlated and decorrelated reflections.
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It looks like nobody read my post.....
seems like most think that a certain target curve...makes the system sing....That is plain wrong...our brain can easily separate the room from the performance..I mean does violins come with tone controls...does a piano...then why should a stereo system...
I tried to mention earlier that the frequency response was adapted to the drivers in the speaker...that a speakers response can't be flat. but must be tailored to the drivers used....and you build the frequency response with the drivers...the cross over region can't be flat or the area will stand out.
if you then try to correct the in room response this balance is upset...and you'll most probably end up worse...minimal phase network.....is just an assumption to a reality that's much much more complex...
By testing raw drivers I know how different drivers with almost the same frequency response can sound...how can any outside system adjust that...??
seems like most think that a certain target curve...makes the system sing....That is plain wrong...our brain can easily separate the room from the performance..I mean does violins come with tone controls...does a piano...then why should a stereo system...
I tried to mention earlier that the frequency response was adapted to the drivers in the speaker...that a speakers response can't be flat. but must be tailored to the drivers used....and you build the frequency response with the drivers...the cross over region can't be flat or the area will stand out.
if you then try to correct the in room response this balance is upset...and you'll most probably end up worse...minimal phase network.....is just an assumption to a reality that's much much more complex...
By testing raw drivers I know how different drivers with almost the same frequency response can sound...how can any outside system adjust that...??
Dan, sometimes you have to EQ frequency before you can even know what to think about what's going on in the time domain.
Not all rooms present the same problems - or, at least, the same parameters in the same proportions.
Frank, I completely agree--rooms/loudspeakers are different. You'd be better off measuring than relying on the old ears. Far better off. 1 measurement will not do.
Dan
A great recording of a symphony has the triangle mic cranked up during triangle parts a lot so that we - again - have the triangle grab our hearing and the recording captures the composer's intentions.
Well I was talking about minimally miked recordings, but failed to mention that.
Of course the ones I wasn't at, I usually don't know the miking used in the recording.
There was a recent link posted to a very good paper on measurements of mastering suites. I was pleasantly surprised to see that they used a dummy head for the measurements. I.E. a polar response that actually mimics that of the human head. We don't hear as much behind us as the omni mic does. We don't hear the room the way the mic does. I've found this to be more important the smaller the room.
Its an interesting start but the measurement would still have to correctly window in the time domain to represent the listening process' integration time needed to build up the tonal balance. MLSSA's adaptive window could be a starting point.
This still wouldn't answer the question of "what is the right reference"? If you took a huge leap of faith and pegged it as a speaker with a flat on axis response with a very particular DI, then you could perhaps use the KEMARed+Adaptive windowed version of that speaker as a reference. This "reference" would change with every room, speaker set up, KEMAR location and "reference" speaker design. There are many radiation patterns and types that could realize the same DI.
Its the reference that's the stumbling block, even with an improved measurement method.
Dave Dal Farra
I have a recording of the Gran Partita that we did (granted, not a whole orchestra) that comes close to "capturing it" . . . right down to the bus going by. Of course it's "live", played straight through, and I've got the direct capture, with no "mix" or edits at all. And I heard it played from multiple positions and in four different venues, so it's difficult not to "hear through" my listening room (essentially a fifth venue), since I "know" what it sounded like from enough different perspectives that I "hear" the band wherever I listen. But I doubt that I'd be able to "place" the instruments if I didn't know our (non-standard) seating. Still, I use it to compare speakers, and when I make changes in my system. I'm really hoping that we present it again soon, so I can "refersh" my ears . . .Having heard recordings of events that I've attended live, I don't remember one that really matched. But I have been fooled into "wow! that sounds right!" on some occasions where I did not hear the actual performance.
I have three other recordings of the work that fail in three different ways. Glover's reading is so terrible that I still wouldn't listen to it again if the recording surpassed all others technically. Mackerras "gets it", and the recording has all the "audiophile" credentials, but it has that "edge" to the sound, and the balance seems to change throughout. It gets well reviewed for its sonics, but I can't give it a thumbs up for "realism". It doesn't *feel* "live" . . . it feels assembled-in-studio (I don't know if it was, or how many mics were used, just reporting how it "sounds" to me). It's like that suddenly-loud triangle where . . no, just no. It's wrong. It' grates. The overall feel is of a bunch of soloists taking their turn . . . not so much because that's the way they're playing it, but because that's the way the recording "presents" it. Schneider gets it more right, and his band plays, and is recorded, more definitely "ensemble" . . . unfortunately a bit too much on the recording end of things . . . the sound is a bit muddled. Of the three it's the most "musical", though, and if I didn't have our own performance it's the one I'd listen to. I hear it as a good performance in a not-so-good hall. But there I am, listening to the music, and we're talking about loudspeakers . . .
Thanks for the references. Definitely something to check out.
DDF. Agree. It's never simple. I think that something like the KEMAR or HAT dummy is a good start, but then there is more to be done. I don't know what that "more" is. But that doesn't stop me from thinking about it!
DDF. Agree. It's never simple. I think that something like the KEMAR or HAT dummy is a good start, but then there is more to be done. I don't know what that "more" is. But that doesn't stop me from thinking about it!
I have a recording of the Gran Partita that we did (granted, not a whole orchestra) that comes close to "capturing it" . . . right down to the bus going by. Of course it's "live", played straight through, and I've got the direct capture, with no "mix" or edits at all. And I heard it played from multiple positions and in four different venues, so it's difficult not to "hear through" my listening room (essentially a fifth venue), since I "know" what it sounded like from enough different perspectives that I "hear" the band wherever I listen. But I doubt that I'd be able to "place" the instruments if I didn't know our (non-standard) seating. Still, I use it to compare speakers, and when I make changes in my system. I'm really hoping that we present it again soon, so I can "refersh" my ears . . .
You should acknowledge the possibility that because you know the performance, you hear it just right. For others, the recording producers have to tweak it for home consumption.
The brain creates the perception from the cues... and fills in what it has too (since it always has to). For example, long before there were human eyes, there were blind spots in retinas. Nobody notices.
Anybody notice their blind spot? Close one eye. Still can't notice it, eh. Good, it means the visual part of your brain is intact... probably.*
*Sure, it is easy to demonstrate there is a blind spot - just slowly swing a finger in from the periphery of vision till it disappears. But eyeballing a scene, there are no holes. Similar effects in hearing, I suppose; anybody have an example?
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MiiB, I think we all read your post, but some of what you say about crossovers, output, and phase is understood as wrong and demonstrated so.
I'll agree we can separate the room from the performance(the loudspeaker's performance) up to a point--that I'd think most would agree with. You can recognize a good speaker in a bad room and a bad speaker in a good room... Still room characteristics will effects timbre/tonality/spectral balance. Below 300-500 Hz, the room actually dominates the speaker. Most here complaining about 'flat' speakers in untreated rooms with a lot of off axis output where the ear is most sensitive could probably agree that the room influences tonal balance. The question a few (or at least Deward) seem to be asking is can you separate the recording from the live performance. Actually, he's not questioning it. If you can do it for one, it's automatically wrong for every other.
Yes you can adapt to your rooms acoustics and even your loudspeaker's response. Well, unless they are too egregious. That's part of the Godel's Theorem that Ben was talking about. 'Good enough' is hard to know. I'd actually say all my speakers in my untreated rooms are good enough for me to enjoy, but they do sound better on more recordings the less prominent early reflections are and the more even the decay is.
The three ways to look at the issue as far as I see is:
If the goal is to sound good, a flat/smooth response with a smoothly falling off axis response and a smooth in room bass response and decay with a diffuse sound field w/i 20 ms would be a reasonable goal.
To reproduce the recording, You'll need the above plus a long ITDG to account for non studio made recordings. This is not easy in a small room.
http://www.wseas.us/e-library/confe...?dfa51120?3e245730?dfa51120?3e245730?dfa51120
To reproduce every live event from altered in unpredictable ways recordings is a great mystery to me and something only Deward seems to know. Maybe someday I can figure that out, but I have no faith in that.

Dan
I'll agree we can separate the room from the performance(the loudspeaker's performance) up to a point--that I'd think most would agree with. You can recognize a good speaker in a bad room and a bad speaker in a good room... Still room characteristics will effects timbre/tonality/spectral balance. Below 300-500 Hz, the room actually dominates the speaker. Most here complaining about 'flat' speakers in untreated rooms with a lot of off axis output where the ear is most sensitive could probably agree that the room influences tonal balance. The question a few (or at least Deward) seem to be asking is can you separate the recording from the live performance. Actually, he's not questioning it. If you can do it for one, it's automatically wrong for every other.
Yes you can adapt to your rooms acoustics and even your loudspeaker's response. Well, unless they are too egregious. That's part of the Godel's Theorem that Ben was talking about. 'Good enough' is hard to know. I'd actually say all my speakers in my untreated rooms are good enough for me to enjoy, but they do sound better on more recordings the less prominent early reflections are and the more even the decay is.
The three ways to look at the issue as far as I see is:
If the goal is to sound good, a flat/smooth response with a smoothly falling off axis response and a smooth in room bass response and decay with a diffuse sound field w/i 20 ms would be a reasonable goal.
To reproduce the recording, You'll need the above plus a long ITDG to account for non studio made recordings. This is not easy in a small room.
http://www.wseas.us/e-library/confe...?dfa51120?3e245730?dfa51120?3e245730?dfa51120
To reproduce every live event from altered in unpredictable ways recordings is a great mystery to me and something only Deward seems to know. Maybe someday I can figure that out, but I have no faith in that.

Dan
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You should acknowledge the possibility that because you know the performance, you hear it just right. For others, the recording producers have to tweak it for home consumption.
The brain creates the perception from the cues... and fills in what it has too (since it always has to). For example, long before there were human eyes, there were blind spots in retinas. Nobody notices.
Anybody notice their blind spot? Close one eye. Still can't notice it, eh. Good, it means the visual part of your brain is intact... probably.*
*Sure, it is easy to demonstrate there is a blind spot - just slowly swing a finger in from the periphery of vision till it disappears. But eyeballing a scene, there are no holes. Similar effects in hearing, I suppose; anybody have an example?
Ben, this is a very good point. I've done a few recordings of concerts. Even with some seriously cheap(in the worst sense of the word) mics, the sounded just like the live event over very poor speakers in a really bad room.
I've also just done an experiment to distort modern recordings in ways similar to 1930s tech. Ones I'm familiar with, I can still pick out what's going on. Ones I'm not familiar with I think I can pick out, but when I play it back I got it wrong. Strangely, your brain actually fills in the blanks. Playing the recording back unaltered, and it's considerably different. I've gotten in arguments about transcribing some of this old music, whose transcription is correct, and why it's so difficult. I'm not sure if some people have learned to shut this 'filling in' problem off or not or if once you hear a modern artist record these old songs, you learn to fill in their new version into what's missing in the original. One thing is clear, most everyone is fooled by their own ear. Maybe everyone is. Mics are not fooled.
Dan
My belief: we aren't really measuring the right thing (in measuring steady state response) so there will always be uncertainty in large room EQ.
David S.
Hi Dave - steady state cannot possibly be right, agreed? - the ear is not a steady state device. As I said before, there is simply no way to deal with or discuss this issue without considering more than simply single point steady state measurements.
My first impulse is to suggest the right test for flatness is to use a stimulus sound approximating the statistical characteristics of music or what is to be reproduced by the music system.* For sure, steady state sine waves are far-off the target as is 1/3 octave pink noise. But there's something like short, zero-crossing-start sine waves (or gated mics) that come close to music.
That is a common standards strategy and no different than anthropometric or miles-per-gallon testing on standard road circuits. While the stimulus chosen by the International DIY Standards Association may not be a perfect rendering of music, it just has to gather reasonable consensus to be good enough.
Now, is that simple idea or a simple-minded idea?
*Something analogous, or at least instructive, happens in the design of halls according to whether they are for music, speech, opera, movies, etc.
That is a common standards strategy and no different than anthropometric or miles-per-gallon testing on standard road circuits. While the stimulus chosen by the International DIY Standards Association may not be a perfect rendering of music, it just has to gather reasonable consensus to be good enough.
Now, is that simple idea or a simple-minded idea?
*Something analogous, or at least instructive, happens in the design of halls according to whether they are for music, speech, opera, movies, etc.
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Now, is that simple idea or a simple-minded idea?
The later.
The later.
so... have you performed some sort of comparative analysis that you could share with us? On the surface at least, the idea seemed like it might be reasonable...
From the annals of screwball-sounding standards:
The esteemed Danish measurement company, B&K, has/had a "floor tapper" in their catalog. It is a little gizmo that pounds 5 small weights into the floor so that your can measure the sound transmission to the living space or apartment below.
B&K tapper
There have to be a dozen aspects and parameters of "floor tapping" that have to be agreed on for their device to be widely accepted as a useful measurement tool or as a standard.
I can't say if anybody else makes a floor tapper or what the history of floor tapping has been.
The esteemed Danish measurement company, B&K, has/had a "floor tapper" in their catalog. It is a little gizmo that pounds 5 small weights into the floor so that your can measure the sound transmission to the living space or apartment below.
B&K tapper
There have to be a dozen aspects and parameters of "floor tapping" that have to be agreed on for their device to be widely accepted as a useful measurement tool or as a standard.
I can't say if anybody else makes a floor tapper or what the history of floor tapping has been.
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so... have you performed some sort of comparative analysis that you could share with us? On the surface at least, the idea seemed like it might be reasonable...
It is important to understand that in objective measurements the signal used is virtually irrelevent. The only exception to this is that the objective measure is only valid at those frequencies for which the input signal has content - i.e. you don;t know what is happening at 100 Hz if there is no 100 Hz in the input signal. But other than that limitation all signals are the same. One can use noise, impulses, music, speech, anything that you want. For any linear system the results will be the same.
It is certainly true that some signals lend themselves better to the analysis phase of any measurement, but once that analysis is done, and it has been, it is found that log swept sine is king because of its unique features. Music would be treated just like noise and in fact this has been wiuth a sound system during a live event by by cross-correlating the sound input to some measured output, even with an audience present. Low levels of noise can also be injected during a performance - so low that they are not audible - and the sound system measured in real-time that way. This later technique yields much more reliable data that the use of the actual music signal since the music signal does not usually have a full spectrum.
From the annals of screwball-sounding standards:
The esteemed Danish measurement company, B&K, has/had a "floor tapper" in their catalog. It is a little gizmo that pounds 5 small weights into the floor so that your can measure the sound transmission to the living space or apartment below.
Floor tapers are used to study structural borne noise in buildings. They have no use in audio reproduction.
Floor tapers are used to study structural borne noise in buildings. They have no use in audio reproduction.
I feel as if Earl is asking me "Have you stopped beating your wife?" - for which there is NO safe reply.
No Earl (or maybe, yes Earl) contrary to the implication of your reply, I am not a monumental idiot, as you imply, suggesting a floor tapper be used as a music simulation. You will be surprised to learn that I was only providing a funny* illustration of a contrived standard that has been manufactured by B&K, a highly acclaimed firm, for 50 years or so.
Ummm, I sure hope nobody but Earl has considered buying one for tuning their music room.
*Informed people know the introduction, "... from the annals of....." is a routine lead-in to something comic or ironic.
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