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Surround sound on a budget

• Intensity-based localization (loosely based on "Ambisonics"; see Winter '95 Computer Music Journal)
  • For each sound source, generate 4-channel "B-format" signal:
    • W: omnidirectional = signal*0.707
    • X: left-right = signal*cos(horizontal_angle)*cos(vertical_angle)
    • Y: front-back = signal*sin(horizontal_angle)*cos(vertical_angle)
    • Z: up-down = signal*sin(vertical_angle)
  • "Decode" combined B-format signal to eight speaker signals:
    • All eight speakers get W.
    • Left speakers get +X; right speakers get -X
    • Front speakers get +Y; rear speakers get -Y
    • Upper speakers get +Z; lower speakers get -Z
  • Amplitude attenuation is proportional to distance_from_listener**2

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