Audio 03 - AA-01901 Identify Audio Buzz or Hum

Buzz or hum in sound system – Questions to determine cause.

• Is this a buzz, hum or hiss – which of these is it?

  • Low pitched:  https://www.youtube.com/watch?v=SVZ2P0KsLic
    • 60HZ buzz – Ground loop
  • Buzz:  https://www.youtube.com/watch?v=ULHwMrWpgUc
    • Usually, a short in the signal path or bad component
  • Hiss:  https://www.youtube.com/watch?v=IMRj1ombxqY
    • Can be bad cables, a short, electronic interference, gain structure, driver damage/failure
  • Distorted “thwump”:  https://www.youtube.com/shorts/aNjnpmzNTXQ
    • Damaged/disconnected driver
  • Distorted buzz:  https://www.youtube.com/watch?v=SXptusF7Puo
    • Audio level is too high at some point in the path (Clipping)

• Is it present when nothing is playing? Or only during Playback
  • If when nothing is playing, probably a ground loop (60Hz electrical hum), short or interference.
  • If only during playback, it could be a short/overload in signal path, blown driver, foreign object on the enclosure, etc.

• Does it sit under the audio, or does it distort the audio
  • If under, probably a ground loop.
  • If the audio is being distorted, could be the amp is overdriving (loud sounds are being clipped – sound like they are buzzing, but softer sounds are OK), could be a blown or detached driver (causes a “thwump or other odd sound in playback), something touching the speaker box and rattling.

• From where in the auditorium is it coming?
  • If we can determine which speaker, that is ideal (Left stage, 2^nd Right surround on the wall, etc.)
  • If not, the general area is still beneficial (behind the screen, right side of the auditorium, etc.)