Although Prof. Choueiri and I have collaborated over the years our goals and end results are now somewhat divergent.
RACE is designed to be adjustble by the end user, to have as large a listening area as possible, and to work well with existing recordings like LPs, CDs, MP3, movies, video etc. It is also works well with virtually any speaker in any room and can even work with laptops and PC speakers. But RACE can normally only deliver a maximum Interaural Level Difference of about 10 dB. It does deliver the full range of ITD up to 700 microseconds. But this is more than enough for music and movies which seldom have values exceeding these and allows full localization at the extreme sides. Also four speaker RACE can provide a full circle of direct sound for movies such as Avatar or any 4.0 equivalent medium. RACE is also in the public domain with products available from several vendors and more on the way. The sound from a left or right RACE speaker is not flat in an RMS measurement sense since the sum of the direct sound and all the later cancellation signals may seem to add up in ways strange to a meter. BACCH is RMS flat. At the listening position, the RACE response is, of course, flat. (Stereo has the reverse problem, the sound at each speaker is flat, but at the listening position there is treble crosstalk combing and a 3dB power boost for bass center sounds) You should all go to Princeton and hear True Stereo. It is truly amazing. In contrast to RACE, BACCH can deliver ILDs of up to 20 dB and this makes it possible to hear sounds in close proximity to the ears from just two very directional frontal speakers. That is, you can hear whispering at ones ear or the bee buzzing around ones head and, if things are really perfect, even behind the head. But such a feat requires special recordings and very stringent attention to detail. It normally does nothing serious beyond RACE for ordinary recordings or movies that have no proximity sound effects. For best results one must use a dummy head microphone at the listening position and get an impulse response which can be used with the basic BACCH algorthim for a particular speaker type, angle and room. There are then no adjustments and you must have a convolver available to use any of these custom filters. You also cannot move forward or back from the speakers or even stand up but there is a multi-fixed seat version now possible. Finally, in Ambiophonics, ambience comes either from hall IR responses via surround speakers or reproduced by a rear crosstalk cancelled speaker pair being fed by a rear recorded pair as in 5.1. The Princeton approach is to deliver ambience only via the front speakers. This may or may not prove feasible. Ralph Glasgal www.ambiophonics.org ________________________________ From: Peter Lennox <p.len...@derby.ac.uk> To: Surround Sound discussion group <sursound@music.vt.edu> Sent: Thu, February 24, 2011 5:22:31 PM Subject: Re: [Sursound] cross-talk cancellation used in binaural sound reproduction Is it so different from Ralph Glasgal's ambiophonic cross-talk cancelling? Dr Peter Lennox School of Technology, Faculty of Arts, design and Technology University of Derby, UK e: p.len...@derby.ac.uk t: 01332 593155 w: http://sparg.derby.ac.uk/SPARG/Staff_PLX.asp ________________________________________ From: sursound-boun...@music.vt.edu [sursound-boun...@music.vt.edu] On Behalf Of Michael Graves [mgra...@mstvp.com] Sent: 24 February 2011 22:16 To: Surround Sound discussion group Subject: Re: [Sursound] cross-talk cancellation used in binaural sound reproduction I have a Carver C-9 Sonic Hologram unit that I bought on Ebay for about $80. It's a nice little demo piece, but limited in its application. That said, it's biggest problem is noise. Of course it's all analogue and built around -10 dbm levels. And all those capacitors are now very old. Has this sort of thing evern been implemented in code, like a VST plug-in? Ideally it would be nice to have it available within the plug-in architecture of the Logitech Squeezeserver that we use for casual audio playback. There are even limited implementations of room correction done in that manner. Michael On Thu, 24 Feb 2011 10:15:40 -0800 (PST), Robert Greene wrote: >I suppose that someone ought to mention-so I shall-- >the Carver Sonic Hologram. >You can still find the devices around(they were >crosstalk cancellation processors). >They work really well, if you do not >mind sitting really still in one spot >(which of course you are going to have >to do for any such system with only two speakers). >And the nice thing is the Sonic Hologram sounds good- >it does minimal damage to the music. > >It is interesting--sort of tells you where the industry was >and still is on surround and so on--that Martin Colloms >writing about the Sonic Hologram in HiFiNews >says that it definitely makes stereo better [and potentially >much better] but that it is just too much trouble... > >Robert > >_______________________________________________ >Sursound mailing list >Sursound@music.vt.edu >https://mail.music.vt.edu/mailman/listinfo/sursound > -- Michael Graves mgraves<at>mstvp.com http://www.mgraves.org o713-861-4005 c713-201-1262 sip:mgra...@mstvp.onsip.com skype mjgraves Twitter mjgraves _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound _____________________________________________________________________ The University of Derby has a published policy regarding email and reserves the right to monitor email traffic. 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