Sound Effects Glossary

In your search for sound effects here or elsewhere on the Web, you may have seen strange acronyms, terms, or abbreviations when describing sound clips.

Here are the more common definitions for words and phrases that sound recordists, editors, mastering engineers, and sound librarians use while working with sound effects.

Sound FX Dictionary


  • int – interior perspective.
  • ext – exterior perspective.
  • dist – distant. The subject is beyond ten meters.
  • cu – close up perspective. The subject is within a meter.
  • ecu – extreme close up perspective. The subject is within ten centimetres.
  • mcu – medium close up perspective. Same as “med dist.”
  • med dist – medium distant perspective. The subject is from one to ten meters away.
  • POV – point of view, or perspective. How the target sound is affected by the position of the microphone including distance, angle, or whether the recording is made inside or outside relative to the sound recorded
  • BG – a background sound. Not the subject of the recording, but present in the recording.


  • accel/decel – accelerate/decelerate.
  • drive/ride – recording of a vehicle with mic in cockpit/cabin, etc.
  • onboard – recording of a vehicle with the microphone placed on the frame or engine (as opposed to inside).
  • away – vehicle is departing, sometimes “out” is also used.
  • by – vehicle is passing by the microphone.
  • up – vehicle is approaching, sometimes “in” is also used.


  • AMB – ambience.
  • ATM – atmosphere.
  • const – constant, sound doesn’t change much over time.
  • Feet, FS, F/S or FTS – footsteps.
  • moves – minor Foley activity, like shifting or shuffling or handling.
  • MS or M/S – mid-side, a recording technique.
  • PZM – pressure zone microphone, a type of microphone.
  • walla – crowd, usually recorded in a theatre, or ADR.
  • wash – distant, airy, and sometimes reverberant crowd.
  • vox – voices.