I tested the two software decoders that I could find in the web a couple of
Stephan Hotto's decoder does SQ, QS, EV Stereo-4 and Dynaquad.
It's a Java application. Plays also in real time.
Marcus Junglas's SQ decoder is here, this is an off-line decoder:
There are instructions in discussion forums how to build quad decoding into
Audition with multiple plugins. I haven't tried that.
The best results I achieved by using AudioMulch and a handful of
PlogueBidule or some other module synthesizer platform works also well.
If you are interested, please email me directly and I can tell you what
you need and
how you build a decoder "contraption".
You should notice that none of these software decoders don't have the
"Logic" properties, that later analog decoders are regarded good at. If
you look for
"proper" SQ decoding, the best option is possibly to find an analog SQ
The software solutions worked allright for me.