Hi Soundfield, guess that's not your real name )) The plan is cracking SQ decoding using Olson's shadow vectors approach. The reason I'm choosing this method is purely logic, as an engineer a 3-axis variable matrix makes so much sense and if you consider the best decoding vectors for all 4 channels for any predominant sound source, the shadow vector method is the only option that gives a perfect decode. As for complexity, I'm planning on doing this all in software running on a 500MHz Philips ARM MCU. Hardware is basically the MCU and 32-bit analogue convertors running at 48k samples per second. Prelimary calculations suggest a 10 band decoder could work at this speed or possibly 96k samples at 5 bands. So far I've been working on simulations to get a mathematically perfect shadow vector decode (digital offers a quite different and more accurate decode than the analogue methods employed in the 70's).

As for other systems, yes already a shadow vector QS decode has been simulated along with other less common systems such as matrix H.

I do have one thing in common with our 'old school' 'national-kid' and that is a labour of love )))