That's all the world needed.....yet ANOTHER matrix decoder to hear not-quite-perfect quad.The BBC really disliked SQ and weren't especially keen on QS. There were many reasons for this, but foremost amongst them were both formats' variously poor mono and stereo compatibility, lack of accurate image localisation and audible phase related artefacts. I'm sure you'll have read the BBC's detailed study reports into the performance of the currently available matrix systems. I don't think any other broadcaster did as much research (if any) into the subject as the BBC and I've no idea why some US stations made the decisions that they did. What the BBC really did like however, was Sansui's encoding and decoding technology, particularly Vario Matrix. They used Sansui equipment as the platform on which to to host the development of something based rather on more on QS than anything else - Matrix H.This had its own peculiarities, and quickly morphed into Matrix HJ and its subtle variants. Commercial Sansui equipment was therefore capable of being simply modified to decode Matrix H and HJ. Sansui released a couple of such decoders for sale in Europe but it was all rather too late as by then the BBC's year long on-air demo of HJ was coming to an end.