BACCH, Ambiophonics, etc

[Ralph Glasgal]

16 minutes ago, semente said:

 

I fail to understand how you can ensure  correct frequency response in the listening spot if you have something blocking direct radiation.

Because in a large surface, all parts of the surface radiate the same sound.  If you block a few square feet, the level drops in front of that area but the direct sound response in all other areas stays the same.  ESLs are great!  The bigger the better, but this is a special situation, and not for general audiophile application.  You could have a screen that goes away when you want pure music or more technically get louder music when you can hear all of the panel.

[semente]

Just now, Ralph Glasgal said:

Because in a large surface, all parts of the surface radiate the same sound.  If you block a few square feet, the level drops in front of that area but the direct sound response in all other areas stays the same.  ESLs are great!  The bigger the better, but this is a special situation, and not for general audiophile application.  You could have a screen that goes away when you want pure music or more technically get louder music when you can hear all of the panel.

 

I would have to try it out or look at some measurements.

Before then I have strong doubts... 

[Ralph Glasgal]

45 minutes ago, semente said:

 

It makes no sense to compare live ambience with reproduction artifacts.

The peaks and dips in concert halls don't add to the realism, they are the reality; I find this a very serious misconception.

If they were registered in the recording they should be presented in the reproduction.

That is the problem.  They are not normally represented in a stereo recording and if they are there by accident they are not reproduced without localization cue distortion.  I understand the purist urge and agree with it.  But when a room reflection looks like a reflection from a concert hall seat, then it is close to pure.  Yes I use real 3d hall impulse responses to listen to stereo music recorded in a different hall.  I have hundreds of visitors and maybe one of them cared.  Having all recorded hall ambience coming from two frontal speakers is crazy if you are a purist.  Having frontal speakers bouncing off listening room walls is crazy if you are a purist.  But you can work with those unavoidable reflections if you combine them with rear speakers and frontal and rear XTC.  It is a very complex process to generate a domestic concert hall and it will never be perfect, but just a hall that most brains can accept as real if not the best hall ever built. 

[semente]

5 minutes ago, Ralph Glasgal said:

That is the problem.  They are not normally represented in a stereo recording and if they are there by accident they are not reproduced without localization cue distortion.  I understand the purist urge and agree with it.  But when a room reflection looks like a reflection from a concert hall seat, then it is close to pure.  Yes I use real 3d hall impulse responses to listen to stereo music recorded in a different hall.  I have hundreds of visitors and maybe one of them cared.  Having all recorded hall ambience coming from two frontal speakers is crazy if you are a purist.  Having frontal speakers bouncing off listening room walls is crazy if you are a purist.  But you can work with those unavoidable reflections if you combine them with rear speakers and frontal and rear XTC.  It is a very complex process to generate a domestic concert hall and it will never be perfect, but just a hall that most brains can accept as real if not the best hall ever built. 

 

I understand this last part.

For me, as long as the timbre (mostly tonal balance and transient response) are realistic I am happy; spatial reproduction is secondary.

[AJ Soundfield]

4 hours ago, Ralph Glasgal said:

Make that substantiated claims in both cases.  Still no matter how wide the sweet area, the stage width is still at 60 degrees or so for standard stereo regardless of the speaker polar pattern.

60 degrees puts me closer to the stage than I ever sit in a concert hall. Plus images could be panned outside if desired. Just not done on most recordings, but I think we've all experienced this with good ol stereo 60.

IIRC there is some Roger Waters music (QRS?) where stuff happens way off to side, as an example.

[Ralph Glasgal]

3 hours ago, semente said:

 

I understand this last part.

For me, as long as the timbre (mostly tonal balance and transient response) are realistic I am happy; spatial reproduction is secondary.

That is the stereo mythic theory.  The undying belief initiated by J Gordon Holt, that the errors in spatial localization cues do not detract from tonal balance, realism, etc.  To prove otherwise, you just need to put pink noise into a pair of 60 degree speakers, and first walk with one ear facing the speakers from left to right.  You will hear the easily audible drastic change in timbre as you pass through the line between the speakers using your ear as a mic.  Then turn facing the speakers and rock left and right as you stand at the 60 degree point and tell us what the rationalization is for using this system exclusively after 88 years.  Black and white photography is fine as an artform and so of course is stereo which needs no apologies because it was never meant to be realistic.

 

I thought this was a computer audiophile forum.  You all disparage what computers can do now.  You could improve on what is out there.  Einstein could say E'=MCsquared, that does not mean he could build a bomb alone.

[AJ Soundfield]

Ok, so after much bewilderment, we arrive at a better spectral presentation with Ambio at 2 slightly different listening area positions.

Now you might be wondering, why the heck is there a cut at 4.5k, approximately 2x the peak frequency in original measurement?

Well, after struggling mightly with the PEQ and RACE, it dawned on me that the PEQ seemed to be applying filters at 2x the desired frequencies!

Ralph, you may want to download the MiniDSP Ambio plug in for 2x4s and check this yourself, to see if its a software glitch or something with my setup, which I doubt (that's why I used the P152 with Stereophile reference measurements). Hard to believe no one with measurement capability (and decent hearing) using these??

The good news: Spectral balance better. Far less "weirdness" there..as expected.

Also, there is definitely a sense of "hall" ambiance and "space" with many classical recordings, extending to the sides and slightly behind.

The bad news is that it feels like watching the orchestra from a distance further back in hall, where the "stage" is narrowed in the area well behind speakers.

Again, early in the process, but not (yet) to my preference. An interesting "effect", but not my version of "realism".

 

 

[Ralph Glasgal]

35 minutes ago, AJ Soundfield said:

60 degrees puts me closer to the stage than I ever sit in a concert hall. Plus images could be panned outside if desired. Just not done on most recordings, but I think we've all experienced this with good ol stereo 60.

IIRC there is some Roger Waters music (QRS?) where stuff happens way off to side, as an example.

You are rather easily satisfied.  While the orchestra may subtend 60 degrees or less, the frontal half proscenium is much wider since you can think of frontal reflections as just more direct instruments.  So all of this frontal directivity is squished into the sixty degrees and there are problems with sewer effects unless you compromise on mic positions, spots, etc. There are also the senses of Envelopment and hall size to add to stage width and depth.  All this is easily demonstrable if you come to NYC, Malaysia, Germany, etc.

 

Images that appear outside the speakers are almost always due to reverse polarity artifacts and are usually of poor quality or even mythic since they seem unstable pressure in the ear sort of thing .  It is certainly a myth if you think you can use this effect in the real product world.  Blumlein mentioned it in his patent.  I called it the Blumlein Conspiracy in my book.

[Ralph Glasgal]

24 minutes ago, AJ Soundfield said:

Ok, so after much bewilderment, we arrive at a better spectral presentation with Ambio at 2 slightly different listening area positions.

Now you might be wondering, why the heck is there a cut at 4.5k, approximately 2x the peak frequency in original measurement?

Well, after struggling mightly with the PEQ and RACE, it dawned on me that the PEQ seemed to be applying filters at 2x the desired frequencies!

Ralph, you may want to download the MiniDSP Ambio plug in for 2x4s and check this yourself, to see if its a software glitch or something with my setup, which I doubt (that's why I used the P152 with Stereophile reference measurements). Hard to believe no one with measurement capability (and decent hearing) using these??

The good news: Spectral balance better. Far less "weirdness" there..as expected.

Also, there is definitely a sense of "hall" ambiance and "space" with many classical recordings, extending to the sides and slightly behind.

The bad news is that it feels like watching the orchestra from a distance further back in hall, where the "stage" is narrowed in the area well behind speakers.

Again, early in the process, but not (yet) to my preference. An interesting "effect", but not my version of "realism".

 

 

 

 

Congratulations!  You are doing great.  You are better with this stuff than me.  You can ask the miniambio people about what you see, they have responded well to other users but are not audiophiles by any stretch of the imagination.  You might try a narrower speaker angle and less delay and more attenuation.  Since if you hear or see coloration that usually means you are not matched to the real angle and are being too aggressive.  You also need to understand that at frequencies above about 4000 Hz, there is really no such thing as meaningful crosstalk so you can choose between the combing of RACE or the similar combing of narrow speaker angle stereo.  In listening tests, wider RACE was preferred but this was not the final word.  It is a very difficult comparison to hear.  Also you need to take into account how the brain works.  So the RMS display on the screen may look bad, but since the extra energy is late in arriving it sounds like a reflection to the brain and so is not heard as a change in timbre despite what it looks like on a response curve.  it is also a lot harder to hear if you also use rear speakers to provide the brain with envelopment and a pinna kick. 

[fas42]

3 hours ago, Ralph Glasgal said:

That is the stereo mythic theory.  The undying belief initiated by J Gordon Holt, that the errors in spatial localization cues do not detract from tonal balance, realism, etc.  To prove otherwise, you just need to put pink noise into a pair of 60 degree speakers, and first walk with one ear facing the speakers from left to right.  You will hear the easily audible drastic change in timbre as you pass through the line between the speakers using your ear as a mic.  Then turn facing the speakers and rock left and right as you stand at the 60 degree point and tell us what the rationalization is for using this system exclusively after 88 years.  Black and white photography is fine as an artform and so of course is stereo which needs no apologies because it was never meant to be realistic.

 

I thought this was a computer audiophile forum.  You all disparage what computers can do now.  You could improve on what is out there.  Einstein could say E'=MCsquared, that does not mean he could build a bomb alone.

 

Well, you can get both: timbre (tonal balance and transient response) and spatial reproduction. Happens automatically if the system is fully competent, through two speakers. And what happens with walking past the speakers exercises then - is nothing! That is, your ear/brain has unscrambled the acoustic message delivered by the two speakers, and has reconstructed what it means, inside your head - the speakers "disappear", the recording content illusion is fully formed.

 

Most people can't comprehend that this is possible - having done the 'trick' so many times, with so many different bits of kit, I have not the slightest doubt that it's universally available ... the hardest thing for many is to understand what the requirements are: extremely clean, as in, low distortion, sound.

[AJ Soundfield]

Frank, please don't derail this thread with your recursive gibberish. Your doing a great job talking to yourself and posting the same "competence" spiel repeatedly in the MCH or Stereo thread. We get it. All your self administered/graded tests are A+ "competent" because Frank said so.

Thanks.

[fas42]

Well, if people claim that a certain number of speakers are necessary for a certain experience, and some people believe that such an experience is possible with a fewer number of speakers, is it good science to say, "Shut up! I don't want to hear a POV that disagrees with what I believe ... well, because I know I'm right!" ?

[AJ Soundfield]

13 hours ago, Ralph Glasgal said:

You are rather easily satisfied.  While the orchestra may subtend 60 degrees or less, the frontal half proscenium is much wider since you can think of frontal reflections as just more direct instruments.  So all of this frontal directivity is squished into the sixty degrees and there are problems with sewer effects unless you compromise on mic positions, spots, etc. There are also the senses of Envelopment and hall size to add to stage width and depth.

Those lateral reflections from stereo 60 speakers are exactly what creates ASW beyond 60, much like listening to an orchestra. Unless is front row, there is no hard image beyond 60..and often a lot less than that. I have no idea what stereo you listen to, but it seems you are referring to a caricature. I grow weary of posting the same links repeatedly, but it has been shown 4 ch is enough for envelopment, the front 2 at stereo 60.

 

Quote

All this is easily demonstrable if you come to NYC, Malaysia, Germany, etc.

Please. If you are trying to sell this idea, I shouldn't have to go anywhere. I have an Ambio processor. If that isn't enough, how is this going to work for consumers?

Malaysia?? How is it that it took me to find what appears to be a software error with the MiniDSP? It's best to rely on folks who have a clue about this stuff.

 

Quote

Images that appear outside the speakers are almost always due to reverse polarity artifacts and are usually of poor quality or even mythic since they seem unstable pressure in the ear sort of thing .  It is certainly a myth if you think you can use this effect in the real pro

Then what the heck do we need cross cancel binaural for??

[AJ Soundfield]

19 hours ago, Ralph Glasgal said:

Because in a large surface, all parts of the surface radiate the same sound.  If you block a few square feet, the level drops in front of that area but the direct sound response in all other areas stays the same.  ESLs are great!  The bigger the better, but this is a special situation, and not for general audiophile application.  You could have a screen that goes away when you want pure music or more technically get louder music when you can hear all of the panel.

Sorry, but I can't accept this. The TV in front of the speakers will cause very early reflections and diffraction. Even a cavity resonance between the 2 large surfaces are possible. A acoustically transparent screen would be a must, so LCD and LED type panels would be a no. An inescapable fact is that cross cancel binaural requiring close placement of the front 2 ch creates as many problems as it purportedly solves, especially with video.

If one listens solo audio and can have a dedicated room, it seems a viable option. Otherwise, no.

[Ralph Glasgal]

17 hours ago, fas42 said:

 

Well, you can get both: timbre (tonal balance and transient response) and spatial reproduction. Happens automatically if the system is fully competent, through two speakers. And what happens with walking past the speakers exercises then - is nothing! That is, your ear/brain has unscrambled the acoustic message delivered by the two speakers, and has reconstructed what it means, inside your head - the speakers "disappear", the recording content illusion is fully formed.

 

Most people can't comprehend that this is possible - having done the 'trick' so many times, with so many different bits of kit, I have not the slightest doubt that it's universally available ... the hardest thing for many is to understand what the requirements are: extremely clean, as in, low distortion, sound.

The walking test is just an easy way to demonstrate that ordinary stereo is not flat.  If you do it with a mic at the entry to your ear canal and compare this response to what you measure right in front of the speaker as Stereophile reviewers do (cheating) you will see that stereo is far from flat and thus is not subject to perfection.  But you can regard it as an art form that like black and white photography has its limitations as far as realism is concerned but can still be appreciates as you indicate by aficionados.  Who knows color may come to be treasured as much as black and white.

[AJ Soundfield]

1 hour ago, Ralph Glasgal said:

The walking test is just an easy way to demonstrate that ordinary stereo is not flat.  If you do it with a mic at the entry to your ear canal and compare this response to what you measure right in front of the speaker as Stereophile reviewers do (cheating) you will see that stereo is far from flat and thus is not subject to perfection.  But you can regard it as an art form that like black and white photography has its limitations as far as realism is concerned but can still be appreciates as you indicate by aficionados.  Who knows color may come to be treasured as much as black and white.

Read more  

Ralph, I'd suggest you not engage Frank as he simply regurgitates the same thing over and over 18,000+ times on various fora. He can't tell you how he does anything he claims - which is sound rivaling your MCH lab and the AT&T PSR 5ch lab, etc., than others have experienced. He claims this is using only two 3" plastic speakers from a Phillips HTIB. Its either a prank or the fact they call him mad Frank over at ASR, take your pick. There will be zero pictures, diagrams, formulas, AES studies or measurements. It's all in his head, no one else has heard it, not one single explanation as to how this is possible other than recursive flowery gibberish. He does this deliberately to derail the actual topic of experiencing BACCH etc, which he will never mention.

You may have missed it, but there was an interesting link about a couple BACCH systems earlier

https://www.computeraudiophile.com/forums/topic/32987-bacch-ambiophonics-etc/#comment-686676

[semente]

I don't know if this is appropriate for the BAACH thread but I've finally found my comments on my brief listening experience of the Aria 3D.

 

On 11/02/2017 at 0:34 PM, STC said:

 

To understand and to see it's potential I would suggest to experiment with

 

https://cloud.aria3d.com/#/welcome

 

 

You need not do anything. Just follow the instruction. Try playing the video or listen to Money by Pink Floyd.

 

 

Sent from my iPhone using Tapatalk

 

On 11/02/2017 at 0:58 PM, semente said:

 

I have tried it on my iMac's speakers and with a pair of budget sealed circumaural headphones and didn't like it; feels weird, like when you put on someone else's glasses with strong correction, and as if someone went overboard with the reverb.

 

I'll try to capture the sound and play it on my main 2 channel system.

 

R

 

 

 

 

Edit: it sounds a bit better with the headphones.

 

On 11/02/2017 at 1:04 PM, STC said:

 

Please check your settings. You are the first person to give such description.

 

Kindly state exactly how you played them? Which track are you listening to now?

 

I think you chose the dry room setting. With Mozart, the sound will be in side your ears chose normal room. And play with virtual stereo and 3D sound.

 

You will get better experience with speakers and much better experience with Ambiophonics and speakers.

 

 

 

Sent from my iPhone using Tapatalk

 

On 11/02/2017 at 1:27 PM, semente said:

 

In my opinion, the Mozart track is a very bad example of stereo...

With the Sennheiser 201s through iMac headphone out the change in timbre of the vocals is quite noticeable.

The Normal Room setting is unlistenable, sounds like a reverb chamber...

 

 

 

With the exception of the Chicago Musical one, other tracks are not fit purpose.

Here the spatial results are interesting but I can hear weird "artifacts"? and the change in tone of instruments and vocals is also quite obvious.

 

 

I can understand the appeal but from what I have heard it's not for me.

 

R

 

https://www.computeraudiophile.com/forums/topic/30741-why-havent-you-tried-immersive-3d-audio-yet/

[AJ Soundfield]

Well look at what I've done so far with the MiniDSP2x4 Ambio plug in (which is supposed to be identical to the miniAmbio). Crazy correction filter (using a near textbook response monopole), possible software errors...yet no mention whatsoever by folks who have been using them. They had no idea. I would take whatever they say with a large grain of salt.

[Kal Rubinson]

2 hours ago, Ralph Glasgal said:

If you do it with a mic at the entry to your ear canal and compare this response to what you measure right in front of the speaker as Stereophile reviewers do (cheating) you will see that stereo is far from flat and thus is not subject to perfection. 

That's a bit of a red herring, Ralph.  Measurement in front of the MLP is a sample of the sound energy in the room at that point.  Measurements in the ear canal are subject to the HRTF (as are all live sounds).

[AJ Soundfield]

25 minutes ago, Kal Rubinson said:

Measurement in front of the MLP is a sample of the sound energy in the room at that point.

I made sure to take 2, but as shown is 1/12 octave. If I were to apply the psychoacoustic smoothing in REW, it would be even smoother. While there is no question that there will be comb filtering with a phantom center, it is certainly not as bad as Ralph seems to make it out to be especially with lateral reflections which will spatially average/smoothen the filtering. Yes, a hard center is better.

[fas42]

3 hours ago, Ralph Glasgal said:

The walking test is just an easy way to demonstrate that ordinary stereo is not flat.  If you do it with a mic at the entry to your ear canal and compare this response to what you measure right in front of the speaker as Stereophile reviewers do (cheating) you will see that stereo is far from flat and thus is not subject to perfection.  But you can regard it as an art form that like black and white photography has its limitations as far as realism is concerned but can still be appreciates as you indicate by aficionados.  Who knows color may come to be treasured as much as black and white.

 

Yes, the response won't be flat - but the key to achieving subjectively satisfying replay is 'tricking' the ear/brain mechanism into doing the DSP for one. This is something I've spent many years exploring, and a key aspect is that subjectively there is an on/off switch inside your head that is triggered, depending upon the quality of the sound - this most likely won't be the case for everyone, but every indication is that it is largely universal.

 

Consider this scenario: you are at one end of the house, and you hear the sound of a piano being played at the other end. Asked, is this real or just a hifi, most times the answer is obvious; then you walk towards the sound, and the question is asked again as you progress; and finally you walk into the room, feet away from the source of the music - but there is a fine curtain between you and the "instrument", and you are asked a final time.

 

For me, doing that test is how I assess playback - this is the on/off switch that triggers - is it convincing, or is it obviously "fake"? I used piano for the example, because it was the instrument most likely to be actually played in a home - but it could have been any type of music, in fact.

 

The response doesn't have to be perfect for the switch to fire - but the amount of low level distortion is absolutely critical. Why? Because the ear/brain can easily adjust for response aberrations, but can't discard audible distortions - the latter flicks the switch off, hard - "it's just a stereo system ..."

[Ralph Glasgal]

 

3 hours ago, Kal Rubinson said:

That's a bit of a red herring, Ralph.  Measurement in front of the MLP is a sample of the sound energy in the room at that point.  Measurements in the ear canal are subject to the HRTF (as are all live sounds).

You got me.  You are absolutely correct.  What I should have said is put the mic just outside the ear where it cannot interfere with the pinna.  I am so used to sticking mics in ears that I just wrote what every AES paper says.  If you do the experiment the right way or just use a dummy head without pinnae or just a seven inch wide football or just put an omni microphone about four inches off the center line you will see the same poor frequency response which is a basic property of every set of speakers listened to at a 60 degree angle.  I was not the first to write about this.  Don Keele Jr. who wrote for Audio Magazine wrote the longest AES paper in history to document this problem.  Nobody at Stereophile/TAS/HiFi Review/The audio Critic, etc has ever written anything about this.  Come out on the AES technical tour and you all can hear it without using a mic.

 

The only point in a room that is truly and honestly representative of what a pair of speakers will sound like to a human listener with two ears is if the frequency response measurements are made with two mics separated by about 7 inches with or without a head between them where the angle to the speakers is 60 degrees even if you want to do it in the near field.  The test signals should be both mono and single channel.  The difference between these two response curves (both speakers to both ears and then just left speaker to left ear, of course) would make the reviews a lot more interesting.  

 

You can just listen to two speakers with white noise and standing sideways use one ear block the other) to hear how the sound changes as you move into the center point and then move away again.  This is why, if you move your seat, a speaker, do a tweak without going back to listen in the exact same spot that things just seem to change in slight but audible ways. etc.  But Stereo is a valid artform and this localization cue distortion which varies with the system and the listener, is what makes stereo so subjective and a viable high end industry.

[Ralph Glasgal]

2 hours ago, fas42 said:

 

Yes, the response won't be flat - but the key to achieving subjectively satisfying replay is 'tricking' the ear/brain mechanism into doing the DSP for one. This is something I've spent many years exploring, and a key aspect is that subjectively there is an on/off switch inside your head that is triggered, depending upon the quality of the sound - this most likely won't be the case for everyone, but every indication is that it is largely universal.

 

Consider this scenario: you are at one end of the house, and you hear the sound of a piano being played at the other end. Asked, is this real or just a hifi, most times the answer is obvious; then you walk towards the sound, and the question is asked again as you progress; and finally you walk into the room, feet away from the source of the music - but there is a fine curtain between you and the "instrument", and you are asked a final time.

 

For me, doing that test is how I assess playback - this is the on/off switch that triggers - is it convincing, or is it obviously "fake"? I used piano for the example, because it was the instrument most likely to be actually played in a home - but it could have been any type of music, in fact.

 

The response doesn't have to be perfect for the switch to fire - but the amount of low level distortion is absolutely critical. Why? Because the ear/brain can easily adjust for response aberrations, but can't discard audible distortions - the latter flicks the switch off, hard - "it's just a stereo system ..."

Make it a symphony orchestra played over two great speakers in a distant room.  It may sound like a real orchestra is at the other end of the house but when you get into the room you will know it is a recording for too many reasons to list here. 

[fas42]

1 hour ago, Ralph Glasgal said:

Make it a symphony orchestra played over two great speakers in a distant room.  It may sound like a real orchestra is at the other end of the house but when you get into the room you will know it is a recording for too many reasons to list here. 

 

Perhaps. If one is keenly aware of precisely how the reverberations should occur then one may pick it; the best analogy to what the experience is like in acoustic terms for symphony hall recordings, is to imagine that your listening room has been transported to inside the venue, and placed in a prime listening position with all parts of the room beyond where a vertical plane through the two speakers intersects with the side walls and ceiling are removed - this is the nature of the illusion that forms.

[Ralph Glasgal]

5 hours ago, Kal Rubinson said:

That's a bit of a red herring, Ralph.  Measurement in front of the MLP is a sample of the sound energy in the room at that point.  Measurements in the ear canal are subject to the HRTF (as are all live sounds).

Here is a better correction.  One can measure one speaker and then tell the reader he is on his own in judging from the data how that speaker pair is going to work in a system.  But speakers have more than just frequency response, etc.  They may have large variations in dispersion, symmetry, etc. which will affect their frequency response when they are used in pairs and the response is measured at about 4 inches off the center line or even at a few such points.  Maybe such a speaker pair would have flatter response at 57 or 64 degrees.  So that is one reason why I try to make audiophiles aware of combing and crosstalk.