active sound cancellation

active sound cancellation

[¦ak·tiv ′saund ‚kan·sə‚lā·shən]
(acoustics)
Any technique in which a control sound source creates sound in a selected region equal in amplitude and opposite in phase to sound that would otherwise exist, but this sound cancellation cannot be maintained in the presence of system changes unless there is also a feedback mechanism.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.