ElectroVoice EVX-4 - Stereo 4 Decoder

[jsrstereo]

In another thread (regarding the EVX-44 decoder), Sonic Wiz posted the following observation:

"The original decoder EVX-4 did the best job I've heard of playing back stereo for simple matrix decoder. And then when you put some Enoch Light on it Shazam!"

I have one also, and have always wondered: The EVX-4 creates stereo rears by way of some simple, non-logic matrix, but are the front channels also affected by the matrix or they simply a straight stereo pass-thru with no signal manipulation/modification?

Thanks for bearing with a non-technoid: John R

 

[Sonik Wiz]

The front chs have a little in phase blending that leaves about 12 dB separation between them when playing stereo with a left (or right) only signal. The rear chs have much more opposite phase (actually opposite polarity) blending that leaves a few dB separation L/R. I think the little EV sounds better than other non-logic decoders because it delivers what the listner expects: wide front seperation with good front to back depth. Specific details can be found in MidiMagics quad pages.

Also unique to early EV encoding is that the encode coefficients were different from the decode coefficients.

 

[Sonik Wiz]

In another thread (regarding the EVX-44 decoder), Sonic Wiz posted the following observation:

"The original decoder EVX-4 did the best job I've heard of playing back stereo for simple matrix decoder. And then when you put some Enoch Light on it Shazam!"

I have one also, and have always wondered: The EVX-4 creates stereo rears by way of some simple, non-logic matrix, but are the front channels also affected by the matrix or they simply a straight stereo pass-thru with no signal manipulation/modification?

Thanks for bearing with a non-technoid: John R

Haha etc. Just found one of these on Ebay. Have a laugh at the product description:

https://www.ebay.com/itm/Electro-Vo...173293?hash=item216c234bed:g:cGMAAOSwbkleYVO2

 

[jsrstereo]

Haha etc. Just found one of these on Ebay. Have a laugh at the product description:

https://www.ebay.com/itm/Electro-Vo...173293?hash=item216c234bed:g:cGMAAOSwbkleYVO2

Dang, wish my unit included all them extra features - guess I shoulda got the Delux version.

 

[Sonik Wiz]

Dang, wish my unit included all them extra features - guess I shoulda got the Delux version.

I couldn't resist it. I sent my 1st ever contact seller to him.

HAHA your product description is hilarious! LCD display where is it? Wireless connection from 1972 unit? XLR connectors show them to me! It includes a tape deck & speakers? And what is the hyper-cardiod part? Oh you must have this confused with a microphone. Good luck with the bidding.

 

[Sonik Wiz]

In checking back the seller cleaned up his listing & the box did sell for $50.00.

 

[par4ken]

I never ever bothered with an actual EV-4 decoder nor a Radio Shack nor Heathkit clone, however I used to use a home-built decoder the design of which came from an article from Electron Magazine from sometime in 1971. As I recall it used four transistors, connected a phase splitters (collector resistor the same value as the emitter resistor). The left and right outputs were then blended together through a pot in phase for the fronts and through another pot out of phase for the rear. This simple decoder could be adjusted for Dyna, EV-4, RM (pseudo QS} or anything in between. I usually used it with the front blend near minimum and the rear at maximum, basically Dyna Quad which worked great on many live recordings, bringing out much hidden ambience.
This brings me to my second point Len Feldman and Jon Fixler developed EV-4, but the original idea (I believe) was developed for Fixler Effect Quadraphonic headphones. It was a way of adding in and out of phase components to the 2 or 4 signals that drive the headphones to increase apparent separation. Koss used a similar idea with their Phase 2 and 2+2 headphones. I recall listening to stereo enhanced by the decoder fed to quad headphones, as the out of phase signals were increased the sense of spaciousness expanded enormously.

 

[MidiMagic]

I didn't bother either. I made my UQ-1 decoder. It does the same thing after the amp.