3-Dimensional Soundstage

If you want a true three dimensional sound stage and imaging from two channel stereo there is really only one game in town. BACCH SP. 

Great post!

People must read about crosstalk and Dr. Choueri research ...

They did not understand generally what are the acoustic conditions of musical and three D acoustic experience in a system/room/ears ...No the solution is not owning a multichannel system so good it could be !

Because the 5 aspects defining a better timbre perception are not related to the number of speakers at all ...But these aspects must be improved by the crosstalk controlling filters that then will improve the spatial qualities of sound then the naturalness of timbre perception as recorded initially ..

Acoustics rules audio gear  not the reverse ...

😊

If you want a true three dimensional sound stage and imaging from two channel stereo there is really only one game in town. BACCH SP.

"More critically, the BACCH filter doesn’t introduce any coloration to the signal."

Not supported from the videos presented here.

Additionally, if the primary intent is to remove crosstalk, why do they recommend it for headphones where crosstalk is not an issue, and why shouldn’t one just buy the best headphones out there for far less $$$?

"More critically, the BACCH filter doesn’t introduce any coloration to the signal."

Not supported from the videos presented here.

 

Additionally, if the primary intent is to remove crosstalk, why do they recommend it for headphones where crosstalk is not an issue, and why shouldn’t one just buy the best headphones out there for far less $$$?

First i want the BACCH filters because i already owned one of the best headphone ever designed and i paid it 100 bucks the only hybrid ever designed a mythical beast for 45 years ...I optimize them after 6 months of working with them ... The AKG K340... There is better on some aspect with some costly headphones but not on all acoustic aspects then it is always a top headphone but very hard to understand and drive 😊

For the alleged added "coloration" ... Read Dr. Choueiri explanation... There is no added coloration and this is why the BACCH filters innovate compared to other crosstalk cancellation dsp ...If the BACCH filters could add coloration they will not be an acoustic revolution but a more or less  useless tool just a toy ...

For the headphone, there is more in the BACCH filters that crosstalk filters only here from the mouth of the beast :

https://www.audiosciencereview.com/forum/index.php?threads/revisiting-speakers-vs-headphones-in-light-of-bacch-and-smyth-realiser.17359/

«The Smyth Realizer has no way of emulating a pair of BACCH-ed speakers. First, in order to emulate BACCH-ed speakers you would need to make the impulse response measurements (needed to produce the headphones filter) with the BACCH filter on, so you would need BACCH4Mac, but even that will not work as the BACCH 3D Sound process consists not only of a Finite Impulse Response (FIR) filter for crosstalk cancelation (XTC), which, in principle, could be measured by an impulse response measurement system (although not easily, as the filter requires a true stereo (aka 2x2) convolution) but also a proprietary mono correction algorithm than cannot be captured by an impulse response measurement.

With the BACCH-hp module of BACCH4Mac, you make an IR measurement with in-ear microphones and head tracking (a process not unlike that the Smyth Realizer requires) and the BACCH-dSP application then automatically produces, from the same measurement, two filters that are applied in series. The first is a head externalization filter that allows emulating those speakers over headphones (that filter plays the same goal as that produced by the Smyth) and the second filter is a BACCH filter for crosstalk cancelling the (headphones-emulated) speakers. For listening, BACCH-dSP applies these two filters in series to the input audio, along with the the mono correction process, to emulate BACCH-ed speakers. At any time, the user, if he so wishes, can bypass the BACCH filter with a click of a button and hear an emulation of the speakers (non-XTCed), which would then be equivalent to what the Smyth Realizer does.

In other words BACCH-hp does what the Smyth Realizer plus gives you the additional option of projecting the perceived sound in 3D space — not having the soundstage anchored at, and limited to, the (headphones-emulated) speakers as in regular stereo listening.

An additional advantage of BACCH4Mac over the Smyth Realizer is that head tracking is done optically (and very accurately) via a regular webcam (or the built-in webcam in your laptop) and therefore does not require that you wear anything on your head in addition to the headphones.

We generally advise not to think of systems like BACCH-hp or Smyth Realizer, as wonderful and magical as they are, as replacements of the audiophile speaker listening experience (for reasons that include that mentioned by maverickronin) but rather as a way to emulate that experience when you are constrained not to turn on your speakers (someone is sleeping nearby, or you are on travel away from your system). No matter how good your headphones are and how accurate the emulation is, the sensation of sound waves hitting you in the face and body, which adds much to the “being there” realism, is in the realm of speakers and real life sources.

I hope that this explanation is helpful.

Please feel free to reply here, and/or write to us at info@theoretica.us if you have more detailed questions.

Regards,
Buddy
info@theoretica.us »

Now about the mono correction algorithm which corrected what one of the ASR forum member called , «One of the (very few) quibbles about BACCH processing in the past was that it seemed to cause a subjective "thinning" of the tonality of instruments or vocals placed dead center in recordings»

https://www.audiosciencereview.com/forum/index.php?threads/mono-correction-algorithm-for-bacch.5721/

Read the explanation of BACCH theoretica :

«The mono correction algorithm is a result of 2 years of research aimed at solving one of the most daunting problems of crosstalk cancellation.

A mono signal in a 2-channel system is defined as one that has 100% correlation between the left and right channels. In real life it is practically impossible to produce a sound from a real acoustic source (or a speaker) with 100% correlation at the right and left ears of a listener, even if the source is equidistant from the two ears, as there will always be a finite amount of left-right de-corelation due to reflections and/or even the slightest misalignment of the head with respect to the source. However, it is very easy to produce a mono recording by having the left and right signals be the same. Any crosstalk cancellation filter, including the BACCH filter, requires a stereo signal (which by definition is not 100% L-R correlated) and therefore has a singularity when the input is mono. This singularity manifests itself as a bass rolloff that becomes more audible as the half-span between the two speakers is decreased below +/- 30 degrees. This fact can be shown mathematically. Therefore, if one plays a mono signal, or a mono-heavy signal (such as some pop music mixes where typically the lead vocalist is mixed in as a mono signal to produce a dead-center image) there would be a bass rolloff (which can be heard as a slight nasal coloration) in the sound of the center image that is audible when the BACCH filter is designed for a speaker configuration that has a speaker span (measured from the position of the listener) that is smaller than that of the regular equilateral triangle (the so-called "standard stereo triangle”). Activating the new Mono Correction algorithm completely fixes this problem. A mono signal, or the center image of a mono-heavy signal, will no longer have any coloration through a BACCH filter and will have the same tonal character as when the BACCH filter is bypassed.

For large speaker span half-angles, say 45 degrees and above, there should be no audible coloration to a mono center image through a BACCH filter and no mono correction would be needed. However, since the speakers of most stereo systems are typically configured with span half-angles smaller than that value, the new mono correction algorithm is required, and is very effective at fully restoring the tonal integrity of the center image, as you noted in your astute comments.

Buddy Gardineer
Senior Development Engineer
Theoretica Applied Physics»

"For the alleged added "coloration" ... Read Dr. Choueiri explanation... There is no added coloration and this is why the BACCH filters innovate compared to other crosstalk cancellation dsp ...If the BACCH filters could add coloration they will not be an acoustic revolution but a more or less  useless tool just a toy ..."

But I can certainly hear a difference in mihorn videos, so there is added (rather subtracted) coloration on my monitor regardless of the good Dr's explanation.

Hey, I know of someone who insists he won a major election and figures that if he says it often enough, people will believe it even if not true, whether he believes it or not.