Bacch Dsp, True stereo?


The latest gimmick seems to be eliminating cross talk as a way to achieve true stereo.

Seems very expensive and works with any speaker.

Another layer of complexity.

Anyone have an opinion on this new fad? Seems a bit neurotic to me

emergingsoul

@pinthrift

Thanks for the excellent review. If crosstalk reduction were more common, more recordings might be made in a more "hands off" way. As I stated earlier, I’ve not heard BACCH myself, but I’ve used a physical divider, and as you experienced I too heard that less processed recordings tend to do the best, except in the case of purely processed electronic recordings, which can also produce glorious spacious presentations. I think it's interesting that you mentioned "Homeless" in your review. That's been an important track for me as I set up different systems because it should sound amazing with it's rich and dramatic vocal dynamics and harmonizing. I think that track does a good job of revealing problems with listening rooms and speaker placement because it requires clear solid energy in most room's transition zone, where rooms have a way of ruining things. 

@emergingsoul

I think you bring up a good point about most high end stereo equipment manufacturers ignoring the crosstalk issue. Why aren’t more people talking about it? I think a big part of it is that for the longest time there wasn’t any really practical way to address it in many listening scenarios. Recordings were made in two channel format, expected to be played back with a stereo pair of speakers, and the shortcomings were self evident and accepted because, as we all know, it can be very pleasant to listen to, and better than mono.

A similar accepted limitation with most video/film presentation is that we don’t expect it to be in 3D. 3D can add a lot to the visual experience, but it’s a lot of extra effort, and unlike with audio, the crosstalk is visually unbearable so some kind of glasses usually have to be worn if a large audience is to enjoy the effect from various viewing angles. With audio the crosstalk also profoundly reduces the quality, but our mind is more forgiving with audio crosstalk than with visual. Early 3D glasses were of the red/blue lens type, and this obviously had a seriously negative effect on the visual experience despite making it 3D. Similar weirdness can happen when attempting to correct audio crosstalk with crude methods. Now with polarized glasses and other methods it’s possible to get a clear, high quality 3D image with accurate color and very minimal visual artifacts. Similarly DSP can be used with audio now to practically remove the crosstalk artifacts we’re already living with while adding hardly any new audible issues. It’s a huge win.

But you are right - it’s more complicated to set up. More players coming on-board with this type of technology could, in time, make it much easier to implement.

About the quality of your components impacting crosstalk - they don’t. It’s a physical setup problem inherent to using two speakers. It takes some specific processing or a special speaker arrangement such as Polk uses to address it successfully. That said, there are different kinds of crosstalk. What BACCH is addressing is inter-aural crosstalk across your head coming directly from the speakers. This is by far the most severe crosstalk that reduces the overall sound quality, degrading the stereophonic effect, and also introducing severe comb filtering for center panned sounds at each ear, and at frequencies we’re very sensitive to. There’s also room reflection crosstalk, where the sound from the right speaker bounces across the room to the far wall and then enters your left ear. I think BACCH may be able to address these early reflections as well to some degree. There is also crosstalk between channels that can occur in electronic devices. This is generally not much of an audible problem in modern electronics.

 

inter-aural crosstalk,

This is interesting have never heard this before. A new term I learned today.

You know a lot about this stuff kudos.

I guess there may be some benefits and the implementation experience as well as spending a lot of money for quality Version of what they offer leads to all kinds of positive reinforcement issues. Once you spend a lot of time with something it’s hard to fall out of love with it.

I think I’ll wait till they do a decent video on software implementation and I’ll take interest in this. Mr. audiofilejunkie should do this since he’s trying to make money off of it.  
 

Crosstalk is a complicated issue and now I understand why people stay away from it.

@emergingsoul  Crosstalk is the reason we aren’t fooled into believing that we are not in a live environment. Hearing content coming from the right speaker with your right ear is expected and the time it takes to travel across your face to your left ear locates that sound in space. The same thing is happening with the left ear. This is why super directional speakers like horns can create a magical image due to almost eliminating crosstalk but the place that this magic happens is very small and usually only works for one person and perhaps one more directly behind them. I’ve personally experienced this. BACCH does this digitally in real time with audio queues in the music. As @asctim above notes it isn’t a manufacture equipment issue, the only way to address it on that end is with a hyper directional system as I described or a software based solution like BACCH. You also noted people aren’t interested in this, perhaps you missed my post. I literally built my entire system around Dr. Choueiri’s research and this is the last and most exciting piece I want to add to my system. I don’t believe it is a complicated issue, just a difficult one to address which is why Dr. Choueiri has spent so many years working on a solution. 
 

Thanks,

Steve 

Very encouraging comments.

So the system is designed for a highly focused Target of one person to achieve results. So group of people probably wouldn't benefit as much.

How come you haven't gotten the system you seem very happy about what it does despite the challenges to implement?

There won’t be any challenges to implement it in my system because it is entirely active and it will be plug and play. The only challenge is money, like many things. I did feel it was important to get the room corrected and have the highest level of DSP processing possible before implementing BACCH. Thus my recent purchase of the dspNexus, which is now processing 8 channels with 12 biquad filters at 192K in real time, the results are stunning. The largest impact in sound reproduction is the speakers, next is the room, and I would say crosstalk is third in my list so it will be my next purchase when I can afford it. It’s really quite simple to implement from my discussions with their team. It simply is added between your source and the speakers and works its magic by using head tracking technology. The initial set up includes using microphones put in your ears to measure your unique ears and head and then it’s set up and you don’t need to do anything else. I’m not sure why you perceive that to be difficult. Much less difficult than measuring the room and developing biquads for my DSP in my opinion. 
 

Thanks,

Steve