A location´s "aural fingerprint" - nonspecific sounds on the upper end (somewhere between 2 000 and 8 000 Hz)  

Each room has a distinct presence of subtle sounds created by the movement of air particles in a particular volume. A microphone placed in two different empty rooms will produce different room tone for each.  
 

• Room tone is recorded during 'production sound recording'

• Room tone is used to match the production sound track so that it may be intercut with the track and provide a continuous-sounding background.

• Room ton may smooth out edit points and give a feeling of life in a sound-deadened studio. The soundtrack "going dead" would be perceived by the audience not as silence but as a failure of the sound system. 

23/3 1997