I'd like to get a copy of this Japanese audio magazine too while you're at it, its the January 2002 issue:
I did an experiment with the W2002's yesterday using a device from Hughes Aircraft Co. (!), its a pretty scientific piece of audio gear that boosts and inserts the stereo difference signal into what you hear. Its adjustable too. The difference signal is whats left when you subtract L from R during playback, and it contains most of the room and/or ambience information in stereo recordings. Hughes developed it and marketed this unit, but Hughes Aircraft being Hughes Aircraft, it didnt exactly catch on with the audio world. Sony saw the potential in it and apparently they license some part of the technology from Hughes. The idea of using the difference signal isnt new.. I think I read there was a small 3 channel stereo movement at one time (long ago) which obviously didnt go anywhere. Theres also a passive way to extract the difference signal in your home system that David Hafler suggested in the 70's, and it works too (I'll post a pic if someones interested.) Where was I. Oh yeah,
Adding the stereo difference signal to headphone listening adds a tremendous sense of spaciousness and air, and through the W2002's it was initially very fun to listen to. After plowing through several CD's and bypassing the unit to compare to the original stereo though, I came to favor the original much more. Headphone listening, for all its limitations, already gives you a deep impression of ambience. What limits headphone ambience is not the quantity, its that the sound is contained inside your head. David Haflers idea of using the difference signal in a home system is for the 3rd speaker (the one containing the difference signal) to be placed behind
the listening position. With a headphone there is obviously is no 3rd speaker, and so you get an amalgam of information too big for its britches.
The original stereo signal sounds powerfully focused and grounded by comparison. Its too bad.. the Hughes unit is very well made and is a precise instrument; its not a piece of audio garbage they cooked up because they needed cash. I think it was an offshoot of their aviation research as a matter of fact.
Oh well. It actually sounds really good in my floor system! But my Sony AV receiver already has a bunch of sound fields and I think one or two of them already use difference signal information by the sound of them.
I'm still very interested in sound processing for headphones, but the difference signal seems best left to floor systems.