Also known as the "Sonic Holocaust" by some, Wikipedia says:
- "Sonic holography", as described in U.S. Patent 4,218,585 was first incorporated in the Carver C4000 preamplifier. It enhances stereo imaging by introducing a delayed and equalized signal from the right channel at the left loudspeaker to cancel the signal from the right loudspeaker at the listener's left ear (and vice versa).
So it appears to be a first of Bob's alright. Some have said SRS was a more advanced version that came out later, but I've never used an SRS system so I won't comment on it.
My Carver C-5 Preamp has it on it and I've been using it since 1995 (same pre-amp) initially with some DefTech BP-2s and then with the Carver AL-III ribbon speakers I still have today (see signature for photo). I'm not entirely sure how well it works with all speakers. It's said to be speaker dependent and some hate how it 'overwidens' the soundstage and supposedly reduces the 'pin-point' nature of the center image. I wouldn't think it would work that well with dipoles, but that's what my AL-III ribbons are and it's FANTASTIC. I think all that matters is the initial direct image gets canceled. Your brain treats the rear wave as reverberant/room type data.
All I know is my center image is just as sharp with or without it, but the soundstage opens up considerably with it turned on. Bass seems slightly elevated (REW tests show a slight increase so it's not my imagination, but it also shows slightly smoother overall response as well; of course that's measuring in stereo which you normally don't do, but does give some idea of the effects it may be having at the listener position). Not all material sounds all that different. It depends on the phase effects, etc. in the recording. I've heard sounds expand as far as a 180 degree arc. It's actually not unlike "Q-Sound" found on some recordings (like Roger Waters' excellent AMUSED TO DEATH album; his 5.1 remix version isn't even close to the Q-Sound original, IMO as at best they image in the same places and somehow sound slightly less musical as well for some reason). It also doesn't work very well with Q-Sound (positions of sounds change in many cases as it seems to be canceling out the same effects, possibly because Q-Sound is doing something very similar on the recording itself, so it's best to turn it off for a Q-Sound recording).
Personally, I think it's great. It's like having the speakers much further apart plus wrap-around to the sides surround all without employing techniques to alter the arrangement. In essence, everything just gets "wider" and more pronounced, although it's possible it sounds a bit different with different speakers (e.g. Billy Idol's Cyberpunk album already has some effects that tend to wrap on their own (very pronounced on my home theater system using matrixed 6-speaker stereo). Sonic Holography pulls the same effect off with two speakers upstairs. I don't know if it's the dipoles or what, but I think the center channel voice is slightly more anchored/clear on my Carvers (feels more like someone is really standing there) with it turned on as well. I hardly ever turn it off after all these years. It's almost always better sounding to me turned on.
