BACCH4Mac Pro Edition: a report

[dallasjustice]

As I think about this, one basic challenge with incorporating additional convolution into BACCH might be head tracking. Simply adding post-BACCH FIR convolution in the form of VST plugin or similar would add unknown delays to the signal processing chain, and thereby delay reaction to head movements. I don't know the psychoacoustics well enough to say whether this would be a problem, but I suspect so based upon what I've read of small head movements being important to sound localization. If my speculation is true, then BACCH would need to have tight coupling to any additional convolution to account for signal processing delays.

I think there are a lot of challenges to BACCH. I’m glad they are trying to move things to software. But I still don’t think it’s a finished product.

Latency could be a problem. But I see other problems too. BACCH seems like an unnecessarily complicated system. I still don’t understand why, if the target customer is the high end audiophile type, they require a budget DAC/ADC (RME baby face) for measurements and routing. There is no reason to not allow the end user to use their own pro audio DAC/ADC. It seems like there’s still a desire to shoehorn hardware into what is mostly a software package. The only thing that needs to be sold to the user is a calibrated custom mic pair, the software, a calibration file, head tracker and instructions.

I love IPads and iPhones. But there’s absolutely no way I could abandon my windows playaback chain for a Mac setup. From a sales standpoint, it makes no sense that BACCH would limit themselves in this way. There are many more windows users than Mac users. This is true even with audio playback. Pretty much all of the DSP software only works on windows. The most popular playback software works best on windows.(e.g. Jriver) Windows machines are also much better for video and live TV. So if the user also has a projector connected to their server (like I do), they will most likely be using a windows machine.

I like elegant, simple and comprehensive software solutions. I also prefer to swim with as many fish as I can. The larger the customer base, the better the software, IME. BACCH’s price point, deployment and incompleteness pretty much guarantee that it will remain a tiny niche product for the foreseeable future.

I hope I’m wrong; but I doubt it.

 

[Scott Borduin]

I I still don’t understand why, if the target customer is the high end audiophile type, they require a budget DAC/ADC (RME baby face) for measurements and routing. There is no reason to not allow the end user to use their own pro audio DAC/ADC.

...

I love IPads and iPhones. But there’s absolutely no way I could abandon my windows playaback chain for a Mac setup.

I like elegant, simple and comprehensive software solutions. I also prefer to swim with as many fish as I can. The larger the customer base, the better the software, IME. BACCH’s price point, deployment and incompleteness pretty much guarantee that it will remain a tiny niche product for the foreseeable future.

I hope I’m wrong; but I doubt it.

BACCH say their solution does work with other DACs. I think they're just trying to provide a complete solution out of the box, to reduce the number of variables in setup and support. And most audiophiles will not necessarily own a high-quality mic preamp.

Apparently, the story is that BACCH was written on Mac because that's what they had in Princeton's labs. I suspect the Mac version might have started as a development and testing platform for the algorithms and runtime, rather than a commercial product per se. For me, I'd definitely have preferred a Windows version but the only mandatory software for me is Roon. I go back and forth as to whether Acourate even adds anything with my ESL speakers.

As to the niche thing, most everything in high-end audio is pretty niche-y to begin with Your system, for instance, is pretty much a one-off combination of equipment and very clever approaches. My ESLs are niche even in the high end. And the total amount of money I've spent through the years on all this stuff is something I won't admit without enhanced interrogation.

The fundamental difference with BACCH for me, and the reason I'm interested in being an early adopter, is that it promises a dramatically different approach to the basic pyschoacoustics of 2-channel playback. My package arrives later this week, right before I leave on vacation, so I'll report back here in a couple of weeks.

 

[dallasjustice]

I’m looking forward to your report.

BACCH say their solution does work with other DACs. I think they're just trying to provide a complete solution out of the box, to reduce the number of variables in setup and support. And most audiophiles will not necessarily own a high-quality mic preamp.

Apparently, the story is that BACCH was written on Mac because that's what they had in Princeton's labs. I suspect the Mac version might have started as a development and testing platform for the algorithms and runtime, rather than a commercial product per se. For me, I'd definitely have preferred a Windows version but the only mandatory software for me is Roon. I go back and forth as to whether Acourate even adds anything with my ESL speakers.

As to the niche thing, most everything in high-end audio is pretty niche-y to begin with Your system, for instance, is pretty much a one-off combination of equipment and very clever approaches. My ESLs are niche even in the high end. And the total amount of money I've spent through the years on all this stuff is something I won't admit without enhanced interrogation.

The fundamental difference with BACCH for me, and the reason I'm interested in being an early adopter, is that it promises a dramatically different approach to the basic pyschoacoustics of 2-channel playback. My package arrives later this week, right before I leave on vacation, so I'll report back here in a couple of weeks.

 

[Theoretica Appl. Physics]

As Mr. Borduin correctly stated, BACCH4Mac can be used with an outboard DAC. Most of our audiophile customers use their own DACs. As Mr. Borduin stated, we include the RME interface because we 1) would like to offer a turnkey system and 2) it has superb and very stable (digitally controlled) mic pres, which are necessary to feed in the BACCH-BM binaural mic signals to the BACCH-dSP software for making the BACCH filters.

Any DAC that can accept digital input from the computer can be easily set up as the output of BACCH-dSP with a couple of clicks. This includes all DACs with USB or Ethernet input. DACs with optical SPDIF input can also be used via the RME's optical out which bypasses all conversion in the RME interface.

A customer who wishes to forego the RME's preamp and ADC stage in favor of his own alternative, can do so easily. Since we cannot guarantee mic L-R level matching with a preamp+ADC hardware that we do not have access to, we do not support it but it is completely possible. While most audiophiles do not have ADCs and mic preamps, many of our Pro Audio users have excellent ADC and mic preamps and have used them easily with B4M.

BACCH4Mac is a finished product (although we keep adding new features and capabilities through updates) and is being used by many audiophiles who love it. It is written for Mac because, as Mr. Borduin stated, its developers are academic researchers and a large fraction of research labs in the physical sciences (like practically all Pro Audio professionals) use Macs. We completely understand the market limitation this causes and we feel sorry that we cannot at present include those who do not wish to use a Mac. We hope to one day extend to Windows and Unix although we have no plans to do so now because at present we would like to continue providing exemplary tech support to our growing customer base with the limited human resources we presently have.

I hope the above adequately addresses the issues you raise.

Regards,
William Guiracoche
Development Engineer
Theoretica Applied Physics

 

[Dialectic]

BACCH4Mac is a finished product (although we keep adding new features and capabilities through updates) and is being used by many audiophiles who love it. It is written for Mac because, as Mr. Borduin stated, its developers are academic researchers and a large fraction of research labs in the physical sciences (like practically all Pro Audio professionals) use Macs. We completely understand the market limitation this causes and we feel sorry that we cannot at present include those who do not wish to use a Mac. We hope to one day extend to Windows and Unix although we have no plans to do so now because at present we would like to continue providing exemplary tech support to our growing customer base with the limited human resources we presently have.

Indeed, the tech support is exemplary--equal to the best that I have encountered--and the product is finished. I've had fewer technical issues with it than I have had with any other large audio purchase that I've made in recent years, and during that time, I have bought products from companies as well-funded as Devialet.

I would add that I strongly prefer Windows as well because I have ~8,000 classical CDs ripped to hard disk. The use of conventional metadata tags, which are totally inadequate for classical music, in Roon and other audiophile players makes the Windows-only player Foobar the only viable option for me. Nevertheless, I am successfully running Foobar in Mac under Wine with BACCH4Mac. Foobar under Wine was a minor pain to set up, but it has been completely free of glitches when used with BACCH4Mac.

I'm sure that a Roon user would have an even smoother experience.

 

[Fitzcaraldo215]

Indeed, the tech support is exemplary--equal to the best that I have encountered--and the product is finished. I've had fewer technical issues with it than I have had with any other large audio purchase that I've made in recent years, and during that time, I have bought products from companies as well-funded as Devialet.

I would add that I strongly prefer Windows as well because I have ~8,000 classical CDs ripped to hard disk. The use of conventional metadata tags, which are totally inadequate for classical music, in Roon and other audiophile players makes the Windows-only player Foobar the only viable option for me. Nevertheless, I am successfully running Foobar in Mac under Wine with BACCH4Mac. Foobar under Wine was a minor pain to set up, but it has been completely free of glitches when used with BACCH4Mac.

I'm sure that a Roon user would have an even smoother experience.

Glad you are enjoying BAACH.

On classical library tagging, friends and I are quite happy with JRiver, which has PC and Mac versions. There is also MusiChi, which is PC only, but friends are very high on it for classical CD. Not sure if either would be easy to convert to from Foobar, however. As I understand it, Foobar does some non-standard things in its tag formatting.

 

[Dialectic]

Just checking in to see if any others have gotten BACCH working in their systems. In my system, the effect continues to be stunning and addictive. Before I got BACCH Pro, I predicted that I would sometimes want to turn BACCH off, but in practice, I never do.

I plan to play with the processing of multichannel recordings through the BACCH 3D Mixer this weekend.

Further, I plan to list recordings that show off the effect particularly well.

 

[Scott Borduin]

I got my orientation session with Dr. Choeiri on Monday, but given my work schedule have had minimal time to listen this week. What I have heard is indeed "stunning and addictive". I am going to have more time to listen this weekend, and have already started taking notes, so a much more lengthy review sometime next week.

Scott

 

[Dialectic]

I keep on listening, getting drawn in (sometimes for hours), and forgetting to write up my further observations.

I'm using BACCH-dSP-dHP (the headphone function) right now. I cannot believe that I ever listened to headphones without this processing.

My efforts so far to mix multichannel recordings to 3D two-channel mixes have been less than successful, but I'll keep playing with it.

EDIT, April 12: To clarify, the 3D mixer works well technically. My lack of success in making convincing multichannel-to-3D stereo mixes with it almost certainly stems from how I'm using it. I may be doing something wrong as simple as failing to map the channels properly when converting multichannel recordings to AIFF. I'll keep working on it.

 

[Scott Borduin]

My observations are somewhat delayed due to temporary turbulence in my listening situation. Due to an adult son being home for the duration of his schooling at least, I've lost access to my more spacious dedicated music listening room, and now am using my dual-purpose media/home theater room. I was using Janszen ESL speakers in that room for music, which worked very well with BACCH, but ESL don't coordinate well with multi-seat multi-channel, and I'd already been looking for high quality LCR options. I found a deal on used Revel Salon2 I couldn't pass up, and they arrived this week. I spent a lot of time setting them up and EQing the room dependent region, and today calibrated them with BACCH. If they didn't work well with BACCH, I'd find a way to accomodate the Janszens in the same room. As it turns out, the Salon2s didn't work as well with BACCH - they worked better! Of course, I made sure the first reflections were damped, and even then the impulse response in the BACCH 3D calibration was not as clean as with the Janszens, but nonetheless the crosstalk cancellation was actually more consistent and the audible results even more awesome.

I have to say, I'm still working on the vocabulary for this. One of the first recordings I put on today after re-calibrating for the Salons was a recent recording of Dvorak's American Quartet with the Jerusalem Quartet on Tidal. The overall emotional impact was overwhelming. Brief snippets of Steely Dan's Aja, Joni Mitchell's Court and Spark, Dvorak 9 with Fischer on Channel Classics were equally amazing. I just finished listening to Jackson Browne's Solo Acoustic Vol 1 - live recording, with many of the warts that implies, but still very dynamic, and even far more dramatic in BACCH.

I promise, I will deliver a more comprehensive and nuanced review in a couple of days. But I'll say this: with the recordings I've listened to thus far, this is the biggest step function change in realism I've heard in a stereo system change in my nearly 40 years as an audiophile. There are caveats and nuances, which I'll get to in due time, but there is little doubt in my mind that this is the very beginning of the end for conventional stereo as the ne plus utra of high end audio reproduction.

Scott

 

[Dialectic]

But I'll say this: with the recordings I've listened to thus far, this is the biggest step function change in realism I've heard in a stereo system change in my nearly 40 years as an audiophile. There are caveats and nuances, which I'll get to in due time, but there is little doubt in my mind that this is the very beginning of the end for conventional stereo as the ne plus utra of high end audio reproduction.

Scott

I couldn't have put it better. I understand why some of us remain skeptical about BACCH, but the proof is in the science and, yes, the listening.

 

[oivavoi]

Interesting points. I still have some problems grasping the main perceptual difference, though. How would you describe subjectively the difference between bacch and non-bacch?

What would be the closest thing to compare it to that I might have heard?

And how does it to compare to, say, a good multichannel setup?

 

[Dialectic]

The closest thing you might have heard is perhaps multichannel, but the BACCH presentation is different.

With recordings of classical music, BACCH provides the acoustic envelopment that one gets from rear channels on multichannel recordings. One can engage and disengage BACCH with a click of the mouse while music is playing, and the first thing I notice when I switch from non-BACCH to BACCH is that BACCH reveals information about the acoustic space in which the stereo recording was made. One hears that information all around one's head with BACCH--on every single recording of classical music that I've tried. This information is almost completely lost in non-BACCH stereo playback, even with excellent systems. The only place I've ever heard this information before is in the concert hall. (I happen to have commercial recordings of a few concerts that I attended (mainly back when I lived in Chicago and went to CSO concerts all the time), so, while acknowledging that memory is imperfect, I have a "reference.")

There's other information that one hears in a BACCH setup that I've never heard in a non-BACCH system, stereo or multichannel. That information relates to what audiophiles would call "image specificity," but for clarity, let's call it placement of instruments in the soundfield. On recordings of classical music played back through BACCH (or BACCH-dHP, which is BACCH for headphones), this is what you hear coming from the side of the room where the speakers are placed. With orchestral recordings, for instance, reproduction of string sections in particular is dramatically enhanced with BACCH. With BACCH engaged, they sound like entire sections of massed string instruments, and the listener gets a more realistic idea of where the players are sitting with BACCH than without.

On recordings of chamber music, BACCH provides clearer information about where the players are sitting than one gets with conventional steewo. More startlingly, BACCH corrects the distortion to the sense of scale that results when one plays back chamber music recordings on a non-BACCH system. On non-BACCH systems, the scale of the chamber ensemble tends to follow the size of the system. Ever heard chamber music played back on the giant Focal speakers, big MBLs, or big Genesis speakers? I have, and, my goodness, chamber ensembles sound enormous on those systems. When I activate BACCH while listening through my 8Cs, the sense of scale is corrected. Chamber ensembles sound like chamber ensembles. Microphone placement of course makes a big difference, but this affects the listener's perception of distance to the musicians, not the sense of scale.

Hope this is helpful, though I'm not doing it justice.

The scary thing about BACCH is that you get used to it. I no longer have interest in listening to music played back through non-BACCH systems. When I listen to BACCH for a few hours (every listening session now turns into a few hours), I sometimes disengage BACCH for a reminder of what non-BACCH stereo sounds like, and that reminder is always painful. I'm not exaggerating.

 

[oivavoi]

Cool. Thanks. Great write-up! Now you really make me want to try it out...

 

[oivavoi]

One more thing: How does speaker directivity affect how BACCH works? Will it work equally good on a pair of electrostats and a pair of omnis? Or is it ideally suited for a particular kind of dispersion pattern?

 

[Dialectic]

One more thing: How does speaker directivity affect how BACCH works? Will it work equally good on a pair of electrostats and a pair of omnis? Or is it ideally suited for a particular kind of dispersion pattern?

My first BACCH experience was with Sanders electrostatics, which are ultra-directional. That is the best system I've ever heard.

The next two best systems I've heard have been BACCH systems with active box loudspeakers.

I don't know how BACCH sounds through horns, omnis, or line sources.

My sense is that, in general, greater directivity is desirable with BACCH. I realize that this stands in opposition to Harman's conclusions about listener preferences.

 

[Arthur Cheng]

Hi SoundArgument, Just happen to see your post here! Glad you are enjoying BACCH now! Greetings from Hong Kong

Arthur

 

[Theoretica Appl. Physics]

My first BACCH experience was with Sanders electrostatics, which are ultra-directional. That is the best system I've ever heard.

The next two best systems I've heard have been BACCH systems with active box loudspeakers.

I don't know how BACCH sounds through horns, omnis, or line sources.

My sense is that, in general, greater directivity is desirable with BACCH. I realize that this stands in opposition to Harman's conclusions about listener preferences.

I am glad oivavoi brought up the question of speakers directivity.

The 3D3A Lab at Princeton University, headed by Prof. Choueiri, who also heads Theoretica, the maker of BACCH-SP and BACCH4Mac (disclosure: I am a development engineer at Theoretica) has been carrying out an extensive study of speakers directivity, see https://www.princeton.edu/3D3A/Directivity.html and the technical papers referenced on that page. The webpage contains a dynamic chart that displays numerous plots of directivity measurements conducted on, 26 different loudspeakers, and counting, in the anechoic chamber of the 3D3A Lab. The speakers can be ranked (using the dropdown menu on that chart) according to various indices characterizing various aspects of directivity. Some of these indices have been recently proposed to the AES for standard characterization of speakers directivity, which has been badly lacking in the field of audio engineering with many manufacturers describe directivity haphazardly due to the lack of standard indices.

The question of how speaker directivity affects BACCH 3D Sound is answered in some detail in the 3rd Q&A on Theoretica’s FAQ page (https://www.theoretica.us/faq.html).

It has been a common wisdom in audio to favor more omni speakers (low directivity), as alluded to by soundArgument reference to "Harman's conclusions about listener preferences”. Indeed without BACCH, the reverb in recordings, no matter how prevalent, is not enough to give a sense of envelopment and spatial realism as the reverb is perceived to emanate solely form the speakers, therefore exciting the room with late and uncorrelated reflections, as omni speakers do, is desirable to avoid a sense of sterile and dry listening space. With BACCH this wisdom goes out the window. BACCH particularly excels in realistically reproducing the reverb in the recording, which is perceived by the listener to be as enveloping as it was in the recording venue, and not confined artificially to the location of the speakers. (In fact, we often demonstrate this to visitors by playing back reverb-rich acoustic recordings through BACCH in an anechoic chamber, where reverb tails as long as many seconds are reproduced with uncanny realism). Therefore more omni directional speakers are not needed for BACCH but can be used as long as the ratio of direct to reflected sound is not too low.

There is however one advantage of using more omni speakers with BACCH that is not mentioned in our online FAQ: the sweet spot for 3D listening with BACCH extends further in front and behind the listener with decreasing directivity. This advantage is not of critical value to most audiophiles, who typically sit in the sweet spot (where the filter is designed), unless they wish to share the 3D image with more listeners sitting behind them in a row.

William Guiracoche
Development Engineer
Theoretica Applied Physics

 

[dallasjustice]

Highly directive loudspeakers are ideal for 3D audio with crosstalk cancellation (XTC), since room reflections (which are weaker when using more directive loudspeakers) directly degrade the level of XTC.

 

[Dialectic]

I've started a list of recordings that I think sound good through BACCH. I'd be very grateful for additions to the list. I'll add to the list in due course.