Dr. Edgar Choueiri explains BACCH

[goat76]

I am neutral about BACCH.

BACCH does what it is intended to do, the program successfully cancels out the sound from each speaker from reaching the opposite ear, and that without altering the tonality in any notable way (at least what I have heard).

The problem is not in the XTC itself, the problem is that most of the content out there is pan-potted multi-mono audio productions in which many sound objects are dependent on hearing both of the loudspeakers with both our ears. As said in the FAQ, the crosstalk is already accounted for in such type of audio production when mixed using loudspeakers without XTC.

 

[Bjorn]

The price of the Theoretica BACCH-SP starts at $23,800, right?
That's just plain ridicolous. Definetly priced to reach a certain crowd.

UBAACH is $980.00. Also very high for a software plug-in IMO.

 

[Bjorn]

I am neutral about BACCH.

BACCH does what it is intended to do, the program successfully cancels out the sound from each speaker from reaching the opposite ear, and that without altering the tonality in any notable way (at least what I have heard).

The problem is not in the XTC itself, the problem is that most of the content out there is pan-potted multi-mono audio productions in which many sound objects are dependent on hearing both of the loudspeakers with both our ears. As said in the FAQ, the crosstalk is already accounted for in such type of audio production when mixed using loudspeakers without XTC.

I think this sums it up very well.

And as previously mentioned; UBAACH does a good job of adding some depth. But with spaciousness/envelopment it's nothing near what two broadband temporal diffusers can do. If anyone of you are in Bergen Norway, I can demonstrate the latter to you. We can switch between the two options, though it's not done in seconds.

 

[Keith_W]

And as previously mentioned; UBAACH does a good job of adding some depth. But with spaciousness/envelopment it's nothing near what two broadband temporal diffusers can do. If anyone of you are in Bergen Norway, I can demonstrate the latter to you. We can switch between the two options, though it's not done in seconds.

What is a broadband temporal diffuser? Would you be able to post a picture please?

Also not sure if you mean "temporal" as in "time", or "temporal" as in the part of the skull where the ears are.

 

[goat76]

I think this sums it up very well.

And as previously mentioned; UBAACH does a good job of adding some depth. But with spaciousness/envelopment it's nothing near what two broadband temporal diffusers can do. If anyone of you are in Bergen Norway, I can demonstrate the latter to you. We can switch between the two options, though it's not done in seconds.

Speaking of Bergen, I lived there for 7 months in my youth back in 2002/2003, I worked with salmon filtration out on Sotra.

Bergen is a beautiful place with all those mountains surrounding the town. Back in 2002, it had great record stores and many cozy cafeterias.
The downside is all the rain, but I guess that makes for many days of listening to music.

Do you still have those automatic machines selling umbrellas?

(Sorry for the OT.)

 

[gnarly]

Who makes commercial stereo recordings exclusively for a particular specific speaker set up? Is it not and has it not for 6 decades been common knowledge among artists/producers/engineers that commercial recordings will be listened to on a multitude of playback systems and devices a high percentage of which will be headphones and/or IEMs as well as car stereos which has no standardization?

Are headphones an effect?

Your logic escapes me. I can't see how whatever playback system, autos, headphones, up mixed multi-channel has anything to do with the concept of "effect or not".

For me the idea of "effect or not" in recorded playback, is how well the system's measured acoustic output matches the stimulus signal (the recording)...ala a transfer function.
Pure math and measurements. Think mono here, like Amir's spinorama. Looking for linear time invariant (LTI) response out of one channel.

Ok so now we move to stereo. Two channels. Should have two speakers, earbuds, headphone cups etc...one for each channel.
Where each channel's system response is identical...only the channels' signal content varies. Looking for identical LTI system response from both channels.

Stereo signal that departs from two channels? It's an effect.
Whether summing the two to mono, of up mixing to multi.
Or the L-C-R matrixing I'm currently running ala Gerzon's work.

Any signal that departs from LTI response (stereo or mono), as BAACH does? It's an effect.
Again, just like the host of FX/plugins available.
As I sees it

 

[gnarly]

They do offer a trial for the Audiophile program. Try it and return it with a restocking charge. You just have to have a Mac. If you don't, you can get one from Costco and return it after the trial.

Thx!
Must admit though. Even if it made the best stereo sound I ever heard...I really have moved away from that kind of sound.
It's why I moved on from electrostats,..... to unity/synergies with prosound SPL and bass capability.
What I have now is so dynamic and powerful, it sounds more real / more exciting to me.
And synergies are the closest sound to stats I've heard, with their point-source like acoustic design that larger speakers typically don't have.

(All that said,, I do strongly prefer studio over live recordings...I think that is often at the root of our preferences).

So anyway, the plugin is all I'm willing to maybe go for...

 

[Bjorn]

What is a broadband temporal diffuser? Would you be able to post a picture please?

Also not sure if you mean "temporal" as in "time", or "temporal" as in the part of the skull where the ears are.

Perhaps not the best term to use, but I'm using it in order to distinguish it from common poor diffusers or what's really more simple scattering devices. It's common that people don't recognize the effect I'm talking about because they have tested either simple scattering units, something very narrow banded, units that absorbs a lot more than they diffuse (i.e. Skyline), or/and something that doesn't effect the phase. Just like speakers, there's a big difference in how diffusers work in regards to directivity.

Broadband here is related to specular energy means above the Schroeder frequency, so normally above 250-300 Hz area and more or less all the way up to the highest frequencies. The latter is something most diffusers don't achieve and is likely a reason why a good number don't always like them. If they stop to diffuse around 4-5 KHz, the frequencies above will be typically stick out in a negative way in a small room.

Temporal is time in acoustics and seen with ETC or the impulse. It's also called phase grating. Some will say that if the diffuser doesn't perform temporal diffusion, it's actually not a true diffuser. An example would be a poly. It disperses the sound but doesn't change the phase. When the phase isn't changed there isn't the same effect of spaciousness and envelopment.

And example of diffuser that is broadband and performs both spatial and temporal diffusion is the RPG Modffractal. It is the best diffuser I've tested and I have tested a good number. It's also possible to get in bigger and deeper versions that goes lower in frequency. Placed enough units together, they will also perform lower than the measurement below.

 

[Bjorn]

Speaking of Bergen, I lived there for 7 months in my youth back in 2002/2003, I worked with salmon filtration out on Sotra.

Bergen is a beautiful place with all those mountains surrounding the town. Back in 2002, it had great record stores and many cozy cafeterias.
The downside is all the rain, but I guess that makes for many days of listening to music.

Do you still have those automatic machines selling umbrellas?

(Sorry for the OT.)

Yes, beautiful city but definetly too much rain and cool weather.
Haven't seen those machines in a while, but haven't been downtown much lately either. So not sure. I wear a Gore Tex rain jacket more than any other jackets here, and it's not a coincedence that we often flee to Greek or the Canary islands. But hey, it's sunny and warm today!

 

[Gwreck]

Your logic escapes me. I can't see how whatever playback system, autos, headphones, up mixed multi-channel has anything to do with the concept of "effect or not".

For me the idea of "effect or not" in recorded playback, is how well the system's measured acoustic output matches the stimulus signal (the recording)...ala a transfer function.
Pure math and measurements. Think mono here, like Amir's spinorama. Looking for linear time invariant (LTI) response out of one channel.

Ok so now we move to stereo. Two channels. Should have two speakers, earbuds, headphone cups etc...one for each channel.
Where each channel's system response is identical...only the channels' signal content varies. Looking for identical LTI system response from both channels.

Stereo signal that departs from two channels? It's an effect.
Whether summing the two to mono, of up mixing to multi.
Or the L-C-R matrixing I'm currently running ala Gerzon's work.

Any signal that departs from LTI response (stereo or mono), as BAACH does? It's an effect.
Again, just like the host of FX/plugins available.
As I sees it

For live stereo recording XTC is actually more accurate(IMHO) to how they were recorded so stereo playback would actually be a distortion of the original. All of the concerns people bring up about BACCH and “realism” Are discussed very thoroughly by Theoretica themselves on their website and I’m pretty sure that with studio recordings they acknowledge BACCH can be very effective but may have unnatural effects.

“At the other end of the spectrum, the sound image would be an artificial one and the presence of extreme ILD and ITD values would, not surprisingly, lead to often spectacular sound images perceived to be located in extreme right or left stage, very near the ears of the listener or even sometimes inside of his head (whereas with standard stereo the same extreme recording would yield a mostly flat image restricted to a portion of the vertical plane between the two loudspeakers).”

 

[Justdafactsmaam]

Your logic escapes me. I can't see how whatever playback system, autos, headphones, up mixed multi-channel has anything to do with the concept of "effect or not".

That’s what we listen to. Unless one has a specific attachment to electrical signals. The sound and the quality of that sound that hits our ears is where final judgement is passed.

For me the idea of "effect or not" in recorded playback, is how well the system's measured acoustic output matches the stimulus signal (the recording)...ala a transfer function.

“Acoustic output” well, that’s your stopping point. I’m concerned with what I hear. Transfer function ends at our ears.

Pure math and measurements. Think mono here, like Amir's spinorama. Looking for linear time invariant (LTI) response out of one channel.

That’s all fine and well and useful information. But it’s not the whole story.

Ok so now we move to stereo. Two channels. Should have two speakers, earbuds, headphone cups etc...one for each channel.
Where each channel's system response is identical...only the channels' signal content varies. Looking for identical LTI system response from both channels.

Stereo signal that departs from two channels? It's an effect.

If you ignore the forest and focus on one tree. But we can isolate any part of the chain and take it out of context. What’s an RIAA EQ without a phono preamp to flatten out the curve? An effect? What’s an ADC without a DAC? A failed signal?

Where in the audio chain you choose to gauge the results matters and choosing the wrong point says nothing about the accuracy of that which is being evaluated.

An “effect” is a label, a category. And a matter of perspective.

Adding reverb to a signal is an effect. It’s clearly unambiguously added.

Adding dither? Is that an effect? If one picks their points deliberately it sure is. But in practice it certainly isn’t. It IS added noise. But the end result, key term “end result” is an audibly more accurate output.

Are room reflections an “effect”? They aren’t on the recording. They are unquestionably added.

So these things do depend on how you look at them and where you choose to gauge results.

You consider crosstalk cancelation an effect
I consider crosstalk an effect

You may consider room correction DSP an effect

I consider rooms to be effects.

My end point where I gauge results is at the ears. That is the final destination.

Whether summing the two to mono, of up mixing to multi.
Or the L-C-R matrixing I'm currently running ala Gerzon's work.

Any signal that departs from LTI response (stereo or mono), as BAACH does? It's an effect.
Again, just like the host of FX/plugins available.
As I sees it

I see it differently. I pick a different point of measure. The ears

 

[Gwreck]

That’s what we listen to. Unless one has a specific attachment to electrical signals. The sound and the quality of that sound that hits our ears is where final judgement is passed.

“Acoustic output” well, that’s your stopping point. I’m concerned with what I hear. Transfer function ends at our ears.

That’s all fine and well and useful information. But it’s not the whole story.

If you ignore the forest and focus on one tree. But we can isolate any part of the chain and take it out of context. What’s an RIAA EQ without a phono preamp to flatten out the curve? An effect? What’s an ADC without a DAC? A failed signal?

Where in the audio chain you choose to gauge the results matters and choosing the wrong point says nothing about the accuracy of that which is being evaluated.

An “effect” is a label, a category. And a matter of perspective.

Adding reverb to a signal is an effect. It’s clearly unambiguously added.

Adding dither? Is that an effect? If one picks their points deliberately it sure is. But in practice it certainly isn’t. It IS added noise. But the end result, key term “end result” is an audibly more accurate output.

Are room reflections an “effect”? They aren’t on the recording. They are unquestionably added.

So these things do depend on how you look at them and where you choose to gauge results.

You consider crosstalk cancelation an effect
I consider crosstalk an effect

You may consider room correction DSP an effect

I consider rooms to be effects.

My end point where I gauge results is at the ears. That is the final destination.

I see it differently. I pick a different point of measure. The ears

This could be fun. Is having a different altitude, humidity, and temperature in the playback room vs the recording space an effect? Is having better or worse hearing than the recording engineer and effect? There are many psychological factors that affect perception so would someone’s mood, personal taste or musical experience be an effect? Would being under the influence of psychoactive substances be an effect? Probably the only way possible to not have any alterations or “effects” would be direct transmission of the recorded signal to one’s 8th cranial nerve.

 

[jimbill]

The price of the Theoretica BACCH-SP starts at $23,800, right?
That's just plain ridicolous. Definetly priced to reach a certain crowd.

UBAACH is $980.00. Also very high for a software plug-in IMO.

The Audiophile edition is $4,980. That is what I have. It includes all the things I listed above. You have to have a Mac and a DAC you can run it through. I just bought a 4-month-old $4,000 Parasound amp (got it for $2,000 from a local enthusiast). There is no comparison as to which purchase made the biggest difference to my listening pleasure.

The SP is an all-in-one component. It is very much aimed at a wealthy market.

 

[Keith_W]

Perhaps not the best term to use, but I'm using it in order to distinguish it from common poor diffusers or what's really more simple scattering devices. It's common that people don't recognize the effect I'm talking about because they have tested either simple scattering units, something very narrow banded, units that absorbs a lot more than they diffuse (i.e. Skyline), or/and something that doesn't effect the phase. Just like speakers, there's a big difference in how diffusers work in regards to directivity.

Thank you for your response. No matter how much I think I know, someone on ASR will show me how little I actually know. I think it's time that I go do some reading on diffusers.

 

[gnarly]

I see it differently. I pick a different point of measure. The ears

I use logic and measurements to define my thinking and help me with audio in general and DIY in particular.
The ultimate judgement though, goes to my ears and my subjective opinion.

Have to say, I need to bow out with you...conversation seems to be much more about debate, than audio.
Your arguments are just too far out, take off in too many inapplicable or irrelevant directions imo, for me to want to follow.
All the best.

 

[Justdafactsmaam]

I use logic and measurements to define my thinking and help me with audio in general and DIY in particular.
The ultimate judgement though, goes to my ears and my subjective opinion.

Have to say, I need to bow out with you...conversation seems to be much more about debate, than audio.
Your arguments are just too far out, take off in too many inapplicable or irrelevant directions imo, for me to want to follow.
All the best.

My response to your inquiry was strictly about audio. Your response here has been mostly ad hominem.

So if you want to bow out with that and ignore the actual content of my response that’s OK with me.

 

[AudioJester]

Is there a simple tool to measure XT and XTC at home?
As in , can you do it with REW?

 

[sweetsounds]

Is there a simple tool to measure XT and XTC at home?
As in , can you do it with REW?

Yes. You would need a dummy head with a mic in each ear. Or the 3dio ears.

Alternatively you can use a headset with two mics and be the dummy yourself. (DPA 4560 is top notch). There are probably cheaper ones.

BACCH includes a binaural headset for exactly this purpose.

 

[Newman]

I use logic and measurements to define my thinking and help me with audio in general and DIY in particular.
The ultimate judgement though, goes to my ears and my subjective opinion.

Have to say, I need to bow out with you [justdafactsmaam]...conversation seems to be much more about debate, than audio.
Your arguments are just too far out, take off in too many inapplicable or irrelevant directions imo, for me to want to follow.
All the best.

Exactly. It's called over-defensiveness. It is ultimately self-defeating and doesn't achieve what the over-defender thinks it does. Hence my sense that the username is ironic.

Single-ended BACCH is what it is. And it sure isn't what it could be.

A good example of over-defensiveness (about the simple fact that it is an effects box when used single-ended on the overwhelmingly dominant catalog of commercial recordings that use multi-mic and mixing), is to take the argumentative position that, since perfect-down-to-the-atom sound wave reproduction isn't happening with any current technology, then "everything is an effect, nyah-nyah-na-nyah-nyah, so there!"

Perceptually, we can get remarkably close in our homes to experiencing what the studio engineers crafted with such care and nuance for us to experience, and heard in their mastering suite, and we can do this without having to replicate physical soundfields down-to-the-atom. Perceptually, that is a non-effect, that is a reproduction. That is a goal worth having, if we are interested in art-as-made. A lot of sound reproduction research over the decades has moved us closer and closer to being able to share that experience. Single-ended BACCH moves away from that.

cheers

 

[Gwreck]

The Audiophile edition is $4,980. That is what I have. It includes all the things I listed above. You have to have a Mac and a DAC you can run it through. I just bought a 4-month-old $4,000 Parasound amp (got it for $2,000 from a local enthusiast). There is no comparison as to which purchase made the biggest difference to my listening pleasure.

The SP is an all-in-one component. It is very much aimed at a wealthy market.

It’s basically hand built and the chassis are individually machined.

Exactly. It's called over-defensiveness. It is ultimately self-defeating and doesn't achieve what the over-defender thinks it does. Hence my sense that the username is ironic.

Single-ended BACCH is what it is. And it sure isn't what it could be.

A good example of over-defensiveness (about the simple fact that it is an effects box when used single-ended on the overwhelmingly dominant catalog of commercial recordings that use multi-mic and mixing), is to take the argumentative position that, since perfect-down-to-the-atom sound wave reproduction isn't happening with any current technology, then "everything is an effect, nyah-nyah-na-nyah-nyah, so there!"

Perceptually, we can get remarkably close in our homes to experiencing what the studio engineers crafted with such care and nuance for us to experience, and heard in their mastering suite, and we can do this without having to replicate physical soundfields down-to-the-atom. Perceptually, that is a non-effect, that is a reproduction. That is a goal worth having, if we are interested in art-as-made. A lot of sound reproduction research over the decades has moved us closer and closer to being able to share that experience. Single-ended BACCH moves away from that.

cheers

When you say “single ended” regarding BACCH what exactly are you referring to. I think I understood what you are trying to say but don’t want to make assumptions?