Spread Spectrum Technologies Trinaural 3-channel "revectorization" processor

Rarely available used, this pure analog unit "algebraically re-vectorizes" the stereo signal into three front channels.  (The extra channel is used to drive a high-quality center speaker.)  According to designer James Bongiorno, the Trinaural eliminates "cross-coupled error signals," which, though necessary for two-channel reproduction, create spurious directional cues, especially when one is not sitting rigidly in the central sweet spot.

Reviews:

David Rich of The Sensible Sound:  "I can conclude the Trinaural processor represents the current state of the art
in three-channel reproduction, and three-channel reproduction represents the
first significant advance in sound reproduction since the introduction of the CD
player . . . . In the end what Trinaural does is lets you get back to being a music lover . . . . With
Trinaural the speakers do not localize. Front-to-back depth is a very real
thing. Woodwinds take on a size and character that one hears live but never in
two channels. Brass glow with full tone but not the harsh edge. Violin sections
really sound like sections, as you can hear the individual players, not some
edgy blob that oozes from the center of speakers. With the Trinaural processor
you can stop that part of your life that involved tweaking components, speaker
placement, etc., and get on with what you really want to do – listen to music." 

(Full review is here:  http://www.ampzilla2000.com/sensiblesoundreview.html)

Kalman Rubinson of Stereophile: "The Trinaural was consistently satisfying with a wide variety of two-channel music. I felt less constrained to sit in my 'serious listening' position of the center of the couch. The performers were always firmly located in the middle of the front of the room, regardless of where I moved, although my perspective on the soundstage changed depending on my proximity to the left or right speaker. This, of course, is exactly what would have happened with real musicians in the room, assuming I had the audacity to walk around as they performed . . . . With Trinaural, the performers were more coherently present in the center of the soundstage, and seemed to have greater depth as well as more discrete layering from front to back (or, in multichannel terms, from front to farther in front). I have yet to hear a two-channel recording in which the integrity of an ensemble was not as good as or better when subjected to Trinaural processing. I can say as much for good multichannel recordings with a discrete center signal, but my "old" two-channel recordings couldn't get there without the Trinaural.  Overall, the Trinaural processor significantly improved most recordings while enhancing the spatial presentation, and had no real deficiencies."

(Full review is here:  http://www.stereophile.com/musicintheround/904music/index.html)

See also http://jamesromeyn.com/#/home-audio-gear/sst-trinaural-processor-by-james-bongiorno-2k-usd/, and Reply #9 of this Audiocircle thread: http://www.audiocircle.com/index.php?topic=116252.0

Details:

My unit is in fine condition; the Audiogon rating of "8" is conservative.  I have the original box.  The manual was apparently online only: http://www.ampzilla2000.com/trinaural_manual.html

At my asking price of $1499, I will include shipping in the continental U.S.  Otherwise, buyer pays shipping.  If you use Paypal, please add the fee. 

A final thought:  I had to choose an Audiogon category for my listing, but "Home theater" and "processor" do not really capture what Trinaural does for your music.  Hear it for yourself!