View Full Version : Fosgate Audionics Pro-Plus digital servo logic surround processor Model Two

louped garouv
03-06-2007, 10:09 PM
any one ever use one of these?

Don C
03-06-2007, 10:25 PM
I have one, but it arrived dead. So I've never heard it.

louped garouv
03-06-2007, 10:29 PM
did you happen to get the manual?

I don' tunderstand what the amplifier inputs are for? (with the jumpers)

hopefully i'll get a chance to play with it soon...

Titanium Dome
03-08-2007, 05:31 PM
Well, I've hesitated to answer this, but my admiration for Jim Fosgate won out. This will at least allow me to wax eloquent on the man if not the equipment.

The Pro Plus stuff from Fosgate Audionics (MK. I) was the first decent implementation of surround sound in the 90s, far outshining Dolby Pro Logic. Pro Logic, when implemented very, very well, was barely acceptable as an alternative to stereo sound on a soundtrack, and virtually never acceptable as music.

Jim Fosgate developed Pro Plus (get it, Pro Logic Plus) independent of Dolby as he always does, working inside his head at home. Once he had the algorithms and topology laid out in his head, he set about building analog, tube based electronics to make a working product. In this case, it was destined to be a Fosgate Audionics product, not a Dolby product, so FA had to do the work to convert everything to a solid state product that could emulate what the tubes were doing. I can imagine Charles Wood, Jim Strickland, and others trying to get all this out of Jim Fosgate's head and into a working product. Egad!

Anyway, the application worked quite well, but the product quality wasn't quite up to snuff. So I'm not surprised that Don's wasn't operational. :(

However, it was the best available at the time; even Bryston paid attention.

The market took a big step forward with Dolby Pro Logic. But, 24dB step and all, Pro Logic stank. The rear channels were mono, rolled off at 7k on top and 100 on the bottom. The center was too strong. The wave started with add on devices, again proving to be frustrating. The refrain, ĎAre the rear speakers on?í

Fosgate had a very interesting circuit called Pro Plus that it introduced in the early 90s. It did a phase/fiddle and created a stereo appearance from the rear, running the tweets out to 20k. It was much superior to Pro Logic. It made surround sound interesting, at last! Fosgate made the add on units and later some preamp/processors. They were the best of their time but, could not be confused with Bryston.

But anguish lingered on because Fosgate and the few other higher end folks trying to do something more interesting with surround, didnít make their gear very well! The switching was noisy and poorly done. The mechanical integrity of the units was OK at best. While it was the best the market had to offer, it wasnít even close to nice two channel gear. Clearly our customers wanted surround sound, but in the quality of good 2-channel stuff.


Titanium Dome
03-08-2007, 05:34 PM
If you want an in-depth look at the creative genius and his process, this Stereophile article will amaze you.


Titanium Dome
03-08-2007, 05:38 PM
Fosgate's relationship with Dolby came about as a result of the impression 6-Axis made as Roger Dressler looked for the successor to Dolby ProLogic. Fosgate developed 6-Axis when he worked for Harman International, and you'll find it incorporated in the HK Citation 5.0 among others.

More info is here:


Titanium Dome
03-08-2007, 05:44 PM
I have a large number of Fosgate products, including some of the latest equipment from the now-defunct Fosgate Audionics (Mk. III). Based on how much I loved the Citation 5.0, I scooped up an FAP T1, then an FAP T1+. I also got a couple of the Hafler/Fosgate hybrid FAA1000.5 amps.

Home Theater Sound wrote:

Jim Fosgate -- surround-sound pioneer!

Jim Fosgate is a fanatic about sound. He developed one of the first good-sounding surround-sound systems, the Fosgate Research TATE 101A, which ended up winning the Consumer Electronics Show Design and Engineering Award back in 1982. After Harman International bought Fosgate Research, Jim created their Citation 7.0, another design with great sonics. He left Harman and created Dolby Pro Logic II, a system that has moved a substantial number of "two-channel" fans into the surround-sound fold. In 2003, Fosgate won a special Emmy Award for the Development of Surround Sound for Television. In all, he holds 25 audio patents.

Fosgate is also a self-proclaimed tube freak. He did all of the development work for Pro Logic II with tubes, then took the design to Dolby Labs to re-create in solid-state. In fact, well-heeled tube fans can buy an autographed version of his prototype Pro Logic II design, the FAP V1, for a cool $13,000. All in all, the Fosgate name is a powerful recommendation in audio. I decided to get a review sample of the $2500 Fosgate Audionics FAP T1 and try it out.

Titanium Dome
03-08-2007, 05:52 PM
Okay, this is the last bit of Jim Fosgate promoting for now.


He's just such a fascinating guy: brilliant, energetic, creative, and optimistic. Is it any wonder I call my HT assemblage the "Two Jims Theatre"? at least 90% of it comes from the legacy of one Jim or the other. ;)

Titanium Dome
03-08-2007, 06:10 PM
I used some Pro Plus gear many years ago. At the time, it rocked as SOTA for anyone wanting to get into "real surround." But the build quality was uneven, and some aspects of the ergonomics betrayed the potential of the technology.

As I recall, and DO NOT rely on my recollection for this, the amplifier inputs were for use with an integrated stereo amp or receiver that did not have pre-outs. Even as I write it, that sounds wrong, but that's a pretty strong memory; yet the RCA ins make no sense in that context. Maybe there was a dongle of some sort.

The front panel display is somewhat quirky. Again, interface design is not a strength here. But there's a shitload of customization possible between the front panel and your little screwdriver poking around the calibration screws in the back. A manual is a must.

Having said all that, I doubt that this piece of equipment will do much more than present you with a piece of history and an out-dated means for getting surround sound out of two channels. If I had one around, I doubt I'd ever fire it up again. It'd be too crude by today's standards.

But that is a nice little piece of history you have there. :)

louped garouv
03-08-2007, 08:51 PM
Well, I've hesitated to answer this, but my admiration for Jim Fosgate won out

thanks very much Mr. Dome,
very much appreciated....

I'll fire her up with some Boleros for front LR and small Sparkomatic era Altecs in the rear...
(after i find the manual :) )

I have some DBX 15"s around....

should be fun to go "back in time"

but for me, it's all new technology...
never really heard the stuff, especially not "critically"....

fun for little investment....

the history is cool too.......

maybe i'll end up using it somewhat unconventionally

how about A7s for front RL, bolero in the center
and wharfedale airedales in the rear
CV SL36Bs for sub?


there's a shitload of customization possible between the front panel and your little screwdriver poking around the calibration screws in the back. A manual is a must.this is what intrigued me the most.....

Don C
03-10-2007, 11:43 AM
Sorry, I can't find the manual, I think that I had one at one time. I think that those jumpers are pre-out and input jacks for the internal amplifier. I guess that they are there so that you can use additional processing on the rear channel speakers. You could also use the jacks to use the built in amplifier as a power amp for some other processor, but it's not very powerful.

louped garouv
03-12-2007, 02:46 PM
no worries, everything helps....

even if just a mention to move along... ;)