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tone control

noun
  1. a manual control used to adjust the relative responses of an amplifier to high, low, and intermediate audio frequencies.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for tone control

tone control

noun
  1. a device in a radio, etc, by which the relative intensities of high and low frequencies may be varied
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012