Dynaquad adapters

[quadsearcher]

Was there ever a Dynaquad/EV/Hafler decoder that was line level and not a passive speaker matrix? I have one DynaQuad record, this drawing came with it, I've read a recent test confirmed that it sounded much better with the passive hook-up than plain stereo, but not discrete at all of course. I'd rather not mess with my speaker hookup for just one record, plus if it was a line level unit I could make a backup for the car. I guess it could be done with a few op-amps, inverting or non-inverting and some summing.

 

[jsrstereo]

Hey Quadsearcher:

In the mid-90's, Fine Line Audio produced the PhaseAround Home Theater Control Center (Model FL3D-100), a totally passive line-level Hafler-type decoder. The rear were mono, but outta phase with each other for a diffuse effect. I've got some info on it around here somewhere, and will try to post it soon. It's the only passive Hafler decoder that I know of.

John

 

[jsrstereo]

John Sunier may have some for sale thru this site:

http://www.binaural.com/binnews2.html

See short blurb at bottom of the Binaural page regarding the PhaseAround.

 

[flavio81]

Was there ever a Dynaquad/EV/Hafler decoder that was line level and not a passive speaker matrix? I have one DynaQuad record, this drawing came with it, I've read a recent test confirmed that it sounded much better with the passive hook-up than plain stereo, but not discrete at all of course. I'd rather not mess with my speaker hookup for just one record, plus if it was a line level unit I could make a backup for the car. I guess it could be done with a few op-amps, inverting or non-inverting and some summing.

You can build one. Search the ESP (Elliott Sound Products) page for the Surround sound decoding circuit.

Basically you want to send the following to each speaker:

L R
. .
. .
. .
L-R R-L

The Sansui QS-1 unit (and all non-logic, non-variomatrix QS and RM units) do something similar but they also sum the front channels a little bit.

What i do in my room is EXACTLY this:

Try it, i think it's the best kept secret in quad... This setup simply sounds like discrete quad -if the discrete quad tape had no gimmicks like panning things in circles, etc-- you have like a full stage of sound. With MANY stereo CDs, some sounds will go back while you have an excellent front stage. It is simply excellent. You need a digital delay of course, and at least tone controls for the rear speakers.

L-R and R-L signals, as mentioned above, can be easily achieved using a simple circuit, or with a QS/RM first generation decoder.

 

[quadsearcher]

jsrstereo, that is very helpful, I haven't contacted him yet, but it made me think about the circuit.
flavio81, I think I have a circuit in mind, but I'll check that site.

Source
L R
^ ^
+ - - +
/ \ / \
__/\/\/\__________/\/\/\_
l l l
l l l
\_oooo_____l___oooo___/
radio shack isolation xformer
_oooo_ _oooo_
/ \ / \
l l l l
\ / \ /
- + - +
RL RR

 

[quadsearcher]

it didn't show up...correctly

 

[flavio81]

it didn't show up...correctly

This is the circuit for getting the L-R signal:

http://sound.westhost.com/project21.htm

The stereo width controller. This gives you "L-a*R" and "R-a*L" signals, where you can adjust "a". Then these two outs are to be passed through a digital delay, i use this one:

http://www.behringer.com/EN/Products/DSP2024P.aspx

Which is a wonderful and cheap unit. So the "L-R" and "R-L" signals go through this unit set at 5-15msec of delay, you get a wide sound field. This unit also has tone controls, so you can achieve the bandwidth limiting for the rear speakers ("159-7000Hz").