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FM-531HD / May 2013
F M - 5 3 1 H D P R O G U I
AGC + SST MENU
The FM‑531HD has three sections dedicated to dynamics control, the Automatic
Gain Control (AGC), Compressor, and Sweet Spot Technology™ (SST). All three are
inextricably linked by DSP algorithms which logically connect and control them. All
three sections will be collectively discussed in one chapter rather than separately.
What is SST?
Unique to Wheatstone models of processing is a special algorithm called SST, which
stands for Sweet Spot Technology™. The SST incorporates control signals from the
input audio, the multiband crossover, and the AGC and Compressor behaviors in order
to derive a special control signal that is used to force the multiband AGC/Compressor
to operate within a specified gain reduction window. By doing so, the medium and long
term “sound” of the processor is quite stable as program elements and incoming audio
levels wander about.
Without the contribution of the SST, the AGC and Compressor sections would not
be able to maintain as consistent a spectral and dynamics texture over widely ranging
signal input conditions. In fact, they would have little advantage over the technology used
for generations in other audio processors which all suffer from the inability to manage
long‑term spectral consistency.
A “broadband AGC” is not used prior to the AGC and Compressor because such
devices know nothing about the output of the multiband section, and it is this output
that determines the overall texture of how a radio station sounds on the air. By using a
multiplicity of control signals the SST is able to calculate a correction signal that exactly
manages the behavior of the multiband AGC and compressor in order to create a consistent
signature sound across a very wide variety of input sources and audio levels.
Summary of Contents for FM-531 HD
Page 2: ...Technical Manual Wheatstone Corporation May 2013 FM HD Digital Audio Processor FM 531hd...
Page 122: ...page A 2 FM 531HD May 2013 A P P E N D I C E S Appendix A General Specifications A 3 Contents...
Page 128: ...page A 8 FM 531HD May 2013 A P P E N D I C E S Appendix B FM 531HD GPI Interface A 9 Contents...
