The "only" problem with headphones playing Binaural recordings is that the image in front of you, or to one side of you, stays with you in front, or to one side of you as you turn your head. The image is precisely located in the position that it was when recorded, and not (incidentally) in your head, like ordinary recordings are when played through headphones
In fact, while I've never tried it, Binaural recordings are said to be very good through speakers, although they're not as capable of the "completely realistic" 3-D imaging that only headphones can deliver.
BTW: If you've never heard of Binaural recordings, or perhaps have never actually listened to them, you certainly owe yourself an adventure into the most believable recorded sound available. Be prepared for an amazing experience.
A Google search will take you to sites with downloadable samples.
Best regards,
TerryO
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This is beside the point really. The point was that reflections are an essential part of stereo as opposed to some of the opinions expressing the need for eliminating reflections completely.
To the OP, I think one thing not discussed much in this thread is resonances - different speakers have them in different amounts and at different frequencies. Certainly speaker designers do everything they (cost-effectively) can to reduce resonances, but they're a fact of life.
One way to see resonances is with a waterfall plot, a 2-d representation of a 3-D plot of frequency vs. volume (as in loudness, not LxWxH) vs. time, and it shows how some frequencies "hang on" longer than others. Googling waterfall plot should give some interesting results.
One might be tempted to just add more stuffing into a speaker box, but of course that's more likely to absorb too much of the wrong frequency band than to actually help any. "Extreme" measures such as making box sides with sand inside can substantially reduce cabinet vibrations, but the driver cones and domes also have their own resonances, as well as inside-the-cabinet sound reflections accentuating certain frequencies.
If you seriously want to learn more, I suggest reading some books in the field. A couple I've perused and found educational are "High Performance Loudspeakers" by Martin Collums and "Loudspeaker Design Cookbook" by Vance Dickason.
One way to see resonances is with a waterfall plot, a 2-d representation of a 3-D plot of frequency vs. volume (as in loudness, not LxWxH) vs. time, and it shows how some frequencies "hang on" longer than others. Googling waterfall plot should give some interesting results.
I'm not sure this helps in that regard. Others' discussions of off-axis response and room treatment may be more practical.
One might be tempted to just add more stuffing into a speaker box, but of course that's more likely to absorb too much of the wrong frequency band than to actually help any. "Extreme" measures such as making box sides with sand inside can substantially reduce cabinet vibrations, but the driver cones and domes also have their own resonances, as well as inside-the-cabinet sound reflections accentuating certain frequencies.
If you seriously want to learn more, I suggest reading some books in the field. A couple I've perused and found educational are "High Performance Loudspeakers" by Martin Collums and "Loudspeaker Design Cookbook" by Vance Dickason.
They are and they aren't.
We are getting into two different areas here, one is freeing a speaker from colorations, the other creating a realistic sound field. These can be sometimes at odds.
The references I mentioned all say that early reflections will color the sound and are undesirable, but the ear is more tolerant of reflections that arrive later in time. There is a directional component also, in that a floor bounce does more damage than a side wall bounce. We can use directional hearing to separate the side wall bounce from the source. Not so easy with a floor bounce below the speaker.
At the same time, with only two channels of audio we need multiple room reflections to create a sense of natural space.
In reading Toole's book, what surprised me most was how he made the case that lots of room reflections were okay, a deader room was not necessarily an ideal. Read the section where the Quad ESL (a dipole) does very poorly in mono tests because it creates a deader sound source in a room. Moving to two Quads in stereo elevates it somewhat but it's still behind the more conventional radiation pattern speakers (don't tell the dipole forum 😱).
Of course, if you have more channels to play with then living in an anechoic chamber or having highly directional speakers may be a good thing.
David S.
Some ill-thought-out ideas about reflections in this thread.
1. If you think YOU are the creative person behind the music, yes, room reflections help you create "your" favourite sound. Toole's advocacy of room-warmth falls into this same category. To some degree, we all are "creators" in reproducing music; but let's not confuse that role with the tasks of proper reproduction, localization accuracy, etc.
Toole emphasizes "warmth" over ping-pong stereo effects. A good lesson for me - localization is only part of the story of listening to music. But it is also true that warmth caused by your room reflections harms localization. What is really wonderful is the warm sound on Tilson-Thomas old DGG recording of Tchaikovsky's Winter Dreams symphony - the music just swells up and out of the little speaker boxes - and I suspect would do so in an anechoic chamber too. Or many recordings made in the non-proscenium Concertgebouw.
2. The reflections in your room have nothing to do the music source. Duh. If you bought a spring-reverberation unit it would add fullness but what has it got to do with the parameters of reverberation in Carnegie Hall? Not only are reflections not essential, they add extraneous sound that makes it harder for your brain to "solve" the sound. But, as in #1, they can add a nice quality to the sound and enhance your experience... while detracting in other senses.
3. Headphones give you splendid sense of the source acoustics - which is what you want. But in "solving" the sound pumped into your ears, your brain is all-but-forced to conclude it is taking place over or within your head because, all things considered including feedback from your neck, that is the spatial localization that computes best*.
*In vision and hearing, your brain struggles to impart some coherence from a mass of sometimes contradictory cues. Room reflections makes this harder to do... but your brain will create a sound-percept as best as it can.
1. If you think YOU are the creative person behind the music, yes, room reflections help you create "your" favourite sound. Toole's advocacy of room-warmth falls into this same category. To some degree, we all are "creators" in reproducing music; but let's not confuse that role with the tasks of proper reproduction, localization accuracy, etc.
Toole emphasizes "warmth" over ping-pong stereo effects. A good lesson for me - localization is only part of the story of listening to music. But it is also true that warmth caused by your room reflections harms localization. What is really wonderful is the warm sound on Tilson-Thomas old DGG recording of Tchaikovsky's Winter Dreams symphony - the music just swells up and out of the little speaker boxes - and I suspect would do so in an anechoic chamber too. Or many recordings made in the non-proscenium Concertgebouw.
2. The reflections in your room have nothing to do the music source. Duh. If you bought a spring-reverberation unit it would add fullness but what has it got to do with the parameters of reverberation in Carnegie Hall? Not only are reflections not essential, they add extraneous sound that makes it harder for your brain to "solve" the sound. But, as in #1, they can add a nice quality to the sound and enhance your experience... while detracting in other senses.
3. Headphones give you splendid sense of the source acoustics - which is what you want. But in "solving" the sound pumped into your ears, your brain is all-but-forced to conclude it is taking place over or within your head because, all things considered including feedback from your neck, that is the spatial localization that computes best*.
*In vision and hearing, your brain struggles to impart some coherence from a mass of sometimes contradictory cues. Room reflections makes this harder to do... but your brain will create a sound-percept as best as it can.
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And of course we get into the area of taste. Right or wrong, or just different, there are different tastes in room acoustics.
The good old "Live End, Dead End" is an example. How you like it depends a lot on taste, but can actually vary by room and by speaker. I tend to prefer reflective diffusion behind the speaker and heavy absorption behind my head. The side walls should be a good mix of both. However, many folks prefer the opposite.
And some rooms will surprise you.
I spent many years working in this space
that has a flat wooden floor and hard plaster and stone walls.
But the acoustics were wonderful for live music, recording or playback. (The odd angles of the ceiling helped).
Acoustics is a subject that can be argued over as much or more than speakers and other audio gadgets. In may ways it's harder.
One or two things I can tell you; I have lived in and visited many home listening rooms that had poor acoustics and nothing was done about it. Curiously, the members of this forum I've visited who have the best acoustic spaces are among those who produce the best sounding speakers and electronics. And who are happiest with what they build. Go figure.
The good old "Live End, Dead End" is an example. How you like it depends a lot on taste, but can actually vary by room and by speaker. I tend to prefer reflective diffusion behind the speaker and heavy absorption behind my head. The side walls should be a good mix of both. However, many folks prefer the opposite.
And some rooms will surprise you.
I spent many years working in this space
An externally hosted image should be here but it was not working when we last tested it.
that has a flat wooden floor and hard plaster and stone walls.
But the acoustics were wonderful for live music, recording or playback. (The odd angles of the ceiling helped).
Acoustics is a subject that can be argued over as much or more than speakers and other audio gadgets. In may ways it's harder.
One or two things I can tell you; I have lived in and visited many home listening rooms that had poor acoustics and nothing was done about it. Curiously, the members of this forum I've visited who have the best acoustic spaces are among those who produce the best sounding speakers and electronics. And who are happiest with what they build. Go figure.
In pursuit of accuracy it seems that room reflections might always be undesirable and a deader room wood be a better room, but research disagrees with that. I would never argue that reflections in my living room bear some equivalence to the acoustics of Carnegie Hall, but studies show that having lateral reflections in a living room will improve our sense of a performing space and help "unlock" the hall signature that is on the recording.
The problem comes from having only two speakers with a limited angular separation. Hearing 2 speaker stereo in a dead room can not be a fully realistic experience. At one time "a window on the original music event" was given as a compliment but now it refers to a lack of envelopment or any sense of a surrounding space. But a window on the live event is the best that 2 speakers can do in a dead room. With more channels we can be idealistic and demand that the room is dead and all sound is straight from the recording. With 2 channels we need some help from the room, even if that is at odds with accuracy. I think that lateral reflections well delayed from the direct sound will have minimal impact on accuracy.
Pano, it is the size of the room and that it is a performance space that makes your recital hall work well with hard materials. I was briefly in the Architectural Acoustics field and concert halls are largely designed with concrete surfaces. Even wood is undesirable because wall flex will absorb bass. If the architect wants wood "for its warmth" it has to be ultra-thick or heavily adhered to concrete behind. If any concert hall surfaces absorb sound then the room volume (ceiling height) must go up to compensate and that costs money.
Regards,
David S.
The problem comes from having only two speakers with a limited angular separation. Hearing 2 speaker stereo in a dead room can not be a fully realistic experience. At one time "a window on the original music event" was given as a compliment but now it refers to a lack of envelopment or any sense of a surrounding space. But a window on the live event is the best that 2 speakers can do in a dead room. With more channels we can be idealistic and demand that the room is dead and all sound is straight from the recording. With 2 channels we need some help from the room, even if that is at odds with accuracy. I think that lateral reflections well delayed from the direct sound will have minimal impact on accuracy.
Pano, it is the size of the room and that it is a performance space that makes your recital hall work well with hard materials. I was briefly in the Architectural Acoustics field and concert halls are largely designed with concrete surfaces. Even wood is undesirable because wall flex will absorb bass. If the architect wants wood "for its warmth" it has to be ultra-thick or heavily adhered to concrete behind. If any concert hall surfaces absorb sound then the room volume (ceiling height) must go up to compensate and that costs money.
Regards,
David S.
Member
Joined 2003
Agree. I usually prefer a "live" room with wide dispersion speakers for stereo. For multichannel, a fairly "dead" room (especially the ceiling) with narrow dispersion LCRs and wide surrounds.
Yep, money costs money! 😉
As for listening room acoustics, let's not forget that recordings are NOT mastered in an anechoic chamber. They are mastered to "sound good" in a room with good acoustics, but not dead acoustics.
As for listening room acoustics, let's not forget that recordings are NOT mastered in an anechoic chamber. They are mastered to "sound good" in a room with good acoustics, but not dead acoustics.
CSDs are fine, but a wavelet more closely correlates with what we will actually hear--frequency resolution in the bass(we have long integration time) and time resolution in the mids(where we have better time resolution) b/c it uses constant percentage bandwidth rather than constant frequency bandwidth. I at least that's my understanding of it. With a CSD, you trade these things--time and frequency resolution. IOW you can't have them both at the same time with CSD. I believe Mr. Waslo and Dr. Geddes say in the 'measurements' thread, linked early on in this thread, that they are best at showing the resonances we are least likely to hear.
Dan
In short: No, CMP simply can't be "real world" EQ'ed (only in theory) as outlined there - and thats really hard to accept. I know.
Regarding "flawed FR measurements": *all* FR measurements of any kind are flawed if CMP enters the picture (no matter what) - its the most basic and stringent definition of FR that does not extend into CMP behaviour - simply a limited concept that does not - and never will - jump the barrier of any discontinuity regarding spectral distribution over time.
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All the discussion here - about room acoustics being part of the audio system or not or to what degree - is actually heavily related to CMP perception and the role that CMP plays in perception of audio in general - tough - is simply not considered as such yet.
May change after some years or so if someone is patient enough to await that...
Michael
CMP behaviour = "Consecutively Min Phase" behaviour
Telling that there is the same "sonic event" happening/ arriving after some time again = echo, diffraction, reflection etc...
Audio and Loudspeaker Design Guide Lines
Michael
Yeah, CMP concept is "such scary" that people resist to look at this simple concept and its conclusions for generations now 🙂
Relating to the topic of this thread (and the endless discussion about room influence on frequency response), CMP concept is capable to teach us (among other) that those discussions "are rather academic" .
This is, because "in room frequency response" actually is a OXIMORON - as the ancient Greek would have labeled it - so - all those discussions *must be* to a vast extent fruitless and boil down to "preferences".
Thats actually the only "honest" answer one can give to :
"...so what else is there?"
🙂
Michael
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hi Michael,
In french we say "le fou croit qu'il sait, mais le sage sait qu'il croit"
this could be traduced as " the fool believes he knows as the wise knows he believes".
For our business the extrapolation is easy : fool = subjectivist, wise = measure guy.
So what to do, listening, trying, having fun...? Bah, it could be worse after all.
In french we say "le fou croit qu'il sait, mais le sage sait qu'il croit"
this could be traduced as " the fool believes he knows as the wise knows he believes".
For our business the extrapolation is easy : fool = subjectivist, wise = measure guy.
So what to do, listening, trying, having fun...? Bah, it could be worse after all.
Your "CMP" (presence of reflections) is covered in the hearing models I have described. Clearly, a speaker in a room full of reflections will have a perceived frequency response. If perception of frequency response is a time windowed event then we can differentiate between early reflections and late reflections. Later reflections are numerous, lower in level and have only broad effect on measured response, little effect on perceived.
The early reflections are a real problem since they fall well into the integration time window and have broad and strong impact on frequency response (both measured and perceived). The fact that they are difficult to correct with simple EQ does not mean that they couldn't/shouldn't be corrected with DSP, or better, fixed in the room.
The thing that stikes me as odd is that so many people are pursuing automatic room correction without asking "what form of response curve should we correct?"
David S.
Some people believe that you can make the room "disappear" by muting reflections as much as possible. If this is done (almost) completely, we've got an anechoic chamber, which - reportedly - is not much fun to listen to music in.
If reflections are only muted to a high degree, our brain is in a awkward situation: The spectral distribution of room modes and the short arrival time of the (faint) reflections tell the brain, that it is in a (rather small) confined space. With this "in mind", the low level of the reflections can't tell the brain "there are no walls". The only rational conclusion for the brain is "I am in a highly damped closed space". Which - for evolutionary reasons - isn't a comfortable impression and might distract from a pleasant musical experience.
Of course all ingredients of this situation can be measured: room mode distribution, arrival time and volume of reflections. But we have to bring all these parts into some context to really understand what's happening. This applies to all measurable data: frequency response, power response, distribution index etc. Isolating any "most important" data does not make things clearer, but will take something away from the truth.
If reflections are only muted to a high degree, our brain is in a awkward situation: The spectral distribution of room modes and the short arrival time of the (faint) reflections tell the brain, that it is in a (rather small) confined space. With this "in mind", the low level of the reflections can't tell the brain "there are no walls". The only rational conclusion for the brain is "I am in a highly damped closed space". Which - for evolutionary reasons - isn't a comfortable impression and might distract from a pleasant musical experience.
Of course all ingredients of this situation can be measured: room mode distribution, arrival time and volume of reflections. But we have to bring all these parts into some context to really understand what's happening. This applies to all measurable data: frequency response, power response, distribution index etc. Isolating any "most important" data does not make things clearer, but will take something away from the truth.
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