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Understanding Signal Flow

Question asked by mdot on Apr 19, 2011
Latest reply on Apr 21, 2011 by BrettG



With the issue of my USBi out of the way, I would like to ask a question more related to actual signal processing.


Although I am no novice to audio and sound, I am just now trying to sharpen my actual signal processing chops. As I look through the tutorials in SigmaStudio, most things I understand (I think), but there are a few that I don't really understand. I would like to kind of talk through what I understand the signal flow of the "Basic Stereo In/Out" example project included with Studio and have you correct me where I'm wrong and answer a couple of questions.



  1. Okay, so the schematic starts off with the standard input block that is routed into an individual volume slider to control the input level.
  2. The signal exiting the volume slider goes to T connetors where it is split into two equal stereo signals.
  3. One stereo signal is sent, unchanged, to a high pass filter.
  4. The second has both channels added together into one mono signal, and is fed into a low pass filter.
  5. The outputs from those filters, are respectively, routed to individual EQs taylored to their specific frequency ranges.
  6. The outputs from the EQs are routed to independant compressors, were a mild compression ratio is applied at signal levels above aprox. -10dB.
  7. Those signals are sent to independant, one sample delay blocks.
  8. The output of the delay blocks has the "high" signal being summed with mono "low" signal and sent to the DACs.


Am I understanding it correctly?



  • In step 4, I know that bass is "non directional" but, what is the advantage of processing this signal as a mono, sum of channels, instead of a stereo signal?
  • In step 5, being that these signals have just exited filters, what is the advantage of using the "shelf" bands on the EQ blocks? Weren't those frequencies just filtered?
  • In step 7, what is the purpose of delaying all of the signals by one sample?


Thanks, in advance for any insights shared...