1. By the late 1980s integrated-circuit manufacturers were working on designing integrated-circuit matrix decoders. 2. This notation can then be expanded to include the notation of Matrix Decoders. 3. The matrix decoder originally employed for this used the Lisztomania ". 4. Early versions of matrix decoders produced synthesized surround that varied from wonderful to weird. 5. In 1973, Sansui introduced the more advanced QS Vario Matrix decoder with 20 dB separation. 6. But the designers of today's matrix decoders devoted extra effort to producing credible surround from stereo broadcasts and recordings. 7. This passive method worked fairly well compared to the matrix decoders of the period, which attempted to reconstruct a surround sound field from a two channel recording. 8. Many Japanese trademarks like Pioneer or Kenwood had matrix decoders with two modes :-SQ and RM . JVC had two modes on their matrix decoder called Matrix 1 and Matrix 2. 9. Many Japanese trademarks like Pioneer or Kenwood had matrix decoders with two modes :-SQ and RM . JVC had two modes on their matrix decoder called Matrix 1 and Matrix 2. 10. There is no intermixing of channels as is done in matrix decoder 4-channel systems such as QS . This was the only discrete quadraphonic phonograph record system to gain major industry acceptance.