I have since heard these same tracks on 5 different systems. I quickly got on the phone with some friends and told them about these amazing files and they were all keen to have a listen. Here is a quick summary of the results.
- My system (horns). Soundstage widens dramatically on some tracks, notably the Billie Eilish track. It goes all the way out to either side of the listener, sometimes very faintly coming from behind me.
- My system (DCA Stealth headphones). Even though these were convolved for speakers, the effect with headphones is quite dramatic. I have described the sound above.
- Friend's system (Linkwitz LX521). Soundstage widens, but not to the same degree as with mine.
- Friend's system (Avantgarde Duo). The effect was disappointing. There was an audibly different sound, but not to any great extent.
- Friend's headphones (Sennheiser HD650). The effect was similar to my headphones in that it was quite dramatic.
I should note that the last system (the Avantgardes) was NOT set up for equilateral triangle listening because of physical limitations of his room. The Avantgardes were pushed up against the wall, and the listening chair pushed up against the opposite wall. The speakers were spaced widely apart to accommodate an equipment rack and TV, and the room was probably too small for the speakers. Likewise, the Linkwitz system also had room limitations. The speakers were too close to the corners, but they were set up in an equilateral triangle listening configuration. My system was the only one where I have complete freedom to move the speakers and listening chair around.
We discussed why the tracks worked on some systems and not on others. These are some of our theories:
- The files were provided for a certain room geometry which some of us were unable to replicate. We suspect that if we had the full version where we can have finer control of the geometry and also binaural microphone recording and head tracking, the effect would be even more pronounced.
- The directionality of the speakers seems to matter. On highly directional speakers like mine, the effect was the greatest.
- If the speaker is placed near the walls, the early reflections probably interfere with the crosstalk cancellation and reduces the effect.
- The Linkwitz is a dipole, which was placed too close to the wall and in a corner. Again, probable interference from early reflections.
Over the next few weeks I will have an opportunity to listen to more systems with the same files. I will get a better idea of what BACCH can do.