Sliding Band (a la Dolby B) Multiband Matrix Decoder


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1K Club - QQ Shooting Star
QQ Supporter
Since 2002/2003
Feb 20, 2003
Midwest USA
I first read about multiband matrix decoders in a Sansui QSD-1 brochure, the QS "Type-A" decoder with the new QS ICs.

Dolby B NR uses a sliding band to extend the NR to lower frequencies depending on the content in the midrange and treble of the input signal.

I've never heard about a multiband (logic assisted) matrix decoder that dynamically changes the crossover frequencies depending on the frequency spectrum of the matrix encoded stereo input.

Although implementing this in a real time decoder may be impossible (may need some sort of lookahead function to detect when a crossover frequency should adjust), an all software decoder that could look over the entire digitized music file should be able to determine when to adjust the crossover frequencies.

Was a music dependent dynamic crossover modifying multiband decoding system considered during the development of the SM decoder?

Kirk Bayne


2K Club - QQ Super Nova
Apr 9, 2012
No actually but its a great idea. It will be very difficult to implement. I will have a think about it. In our encode we vary the matrix parameters in accordance with the surround content.