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3D Audio and individual Hearing.


Active Member
Mar 7, 2017
Klang Valley
In this this context I refer to 3D audio that involves crosstalk cancellation.

[For readers, unsure what or how it supposed to sound, can get an idea with your recent iPhones when you play ‘Edgar the barber’ from Apple Music. Hold the phone close to your face and adjust until you hear the snipping is heard from the back of the head to the ears. Rotate the phone to change the left and right side speakers. For me it works when I rotate the phone so that the left is heard in the right ear. With the correct orientation I could only sense the snipping at the back when you moves towards the end. Ideally, it should sound like listening to it with headphones since it was a binaural recording.]

I have used almost all the crosstalk DSP such as RACE, AMTRA, Soundpimp, AmbiophonicsDSP and others while being developed. More recently, BACCH for Windows which didn’t work for my system. I don’t think anyone in my country is using BACCH4Mac or they are keeping low profile if they used it.

I have always thought BACCH SP is the gold standard because reading from the reviews and Choueiri claiming that he could make the fly circle around the head something I couldn’t do with other DSPs. Although, I could perceive the scissors snipping at the right and back of the head on the right side towards the tail end of ‘Edgar the barber’ but the left is always a frontal perception. I also refer to Howard Kneller’s review of BACCH where he said “ The scissors and shaver clearly circled the dummy head, moving from front to back and from top to bottom of the head.” Some users defined them to be near the ears.

After about 15 years, I finally perceived the “Edgar the barber” snipping from left to right behind my back when I auditioned Ruark R7 which came with its own crosstalk cancellations. It startled me because I couldn’t do it with other DSPs but here I am hearing the snipping clearly behind my head from left to right. This impressed me because there was no measurements or adjustments and it worked so well right out of the box. I then auditioned three other tracks that I am familiar with but they are not outstanding and probably just an incremental improvement then the standard stereo. This made me more curious. How does the cancellation work for binaural recording better than the stereo? The implementation should be the same but why one sounded so accurate while the other not so much?

BACCH Labs would have done their product testing before the release of BACCH for Windows yet it didn’t work for me. Is there something else beyond measurements?

I looked at my system. And then I tried something different and the magic happened. Yes, Edgar is now snipping behind my head. Musical tracks (some) have a layer just behind the head and the bee indeed circles the head. Although, I could never make the bee to circle around my head before this I have other listeners perceived it be so. They perceive it so based on my own hearing adjustment which didn’t work for me but worked for others or so they claimed as I am always skeptical of people’s localization and description ability when it comes to sound.

In conclusion, unless there is a standard that all listeners perceive the same location with XTC we are just playing a guessing game because I don’t think one can predict how someone hearing really works on measurements alone. It may work for some better than others. Individual adjustment is necessary but this involves proper reference and SOP so that the listeners really hearing what they are supposed to hear. Same measurements have given me different locations on different days. Unless, users actively involved in the settings and adjustment, the end users are just perceiving some better version but without ever knowing if that’s actually the correct settings. And this is where the trade secrets reside for crosstalk cancellation. This parameters involves more than ITD and ILD and allowing users to control them allows them to know how the program works.
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