I'm trying to understand if the phase inverting and signal summing capabilities of some DSPs (Helix?) might help me deal with a challenge I'm facing ….

Background
  • > 2019 Honda Ridgeline RTL-E (with ANC disabled via module disconnect)
  • > OEM amp/DSP has 8 output channels, one for each speaker (FR L&R Tweeters, FR L&R Woofers, FR Center, Rear L&R, Sub)
  • > Most vehicle generated voices and tones are on FR Center along with a mono music signal apparently consisting of simple L+R. So, using "V" for vehicle voices and tones distinct from music, let's call the OEM FR Center signal (L+R+V) for this discussion.
  • > There is no method within my capabilities to 'extract' "V" as a discrete analog signal from the OEM system ("V" is generated and combined with the L+R music within the OEM amp/DSP module based on several digital CAN inputs + analog music input from the "HU" and I'm not an electronics hacker)

Objective

Try to 'cancel' the L and R (music) component of the (L+R+V) FR Center OEM amp output so that the FR Center can be used as a DSP input>output to retain vehicle generated voices and tones without screwing-up music imaging / staging.

My (maybe wrong) Understanding of Theory
  • In theory, this phase inverting and signal summing scheme would achieve my objective: [(L+R+V)+([email protected]*)+([email protected]*) = V] , is that correct?
  • For that to work, each instance of L and R must be the exact same amplitude (as well as frequency of course) at every instant in time, is that correct?
If my above understanding of theory is flawed, please let me know, stop reading, and thanks for your time (any other approach for solving my challenge would be most appreciated)

Real World Implementation (?)
  • I believe that in my case the Rear L and Rear R signals 'match' the frequency of the respective FR Center L & R components (but maybe not close enough to cancel if phase-inverted due to minute differences in the amp/DSP circuitry?).
  • I have no reason to expect the Rear L&R signals to match the amplitude of their FR Center counterparts, and I'm skeptical that I can force an 'exact amplitude match' sufficient to achieve cancellation using level-setting controls in either the OEM system or the external DSP.

Bottom Line Question - Am I on a "Fool's Errand" pursuing this line of thought for upgrading my Ridgeline system in a way that offers 'no compromise' for both music and vehicle features?

Anyone see a different possible / better way to accomplish the 'no compromise' objective given the constraints descibed?

Thanks In Advance