An automatic remote control device and method which compensates for
ambient, environmental noise changes and sudden changes in program
material volume. The microphones and circuitry associated with the volume
control apparatus are located in an autonomous, preferably portable,
remote control unit that will work with any existing audio/video device
that is configured to respond to a remote control input. In one
embodiment, the remote control device comprises a microprocessor, at least
one directional microphone for receiving a sound level emitted from a
sound-emitting device, and at least one omni-directional microphone for
receiving the total noise level in the vicinity of the remote control
device. The microprocessor located in the remote control device utilizes
the received sound level and the total received noise level to calculate a
reference sound-to-noise ratio. If a volume up/down control is pressed by
the operator, the remote control device sends the appropriate signal to
the sound-emitting device to increase or decrease the sound level, and a
new reference sound-to-noise ratio is calculated. If the volume up/down
control has not been used, a timed polling loop periodically measures the
sound level and the total received noise level so as to calculate a
current sound-to-noise ratio and to determine whether the sound-to-noise
ratio has changed. If the sound-to-noise ratio has changed, then the
remote control device sends the appropriate signal to the sound-emitting
device to adjust the sound level so that the original sound-to-noise ratio
is maintained. Hysteresis, in which the device determines whether a
pre-determined amount of time has passed since the device last adjusted
the sound level, is preferably utilized to prevent continuous fluctuations
of the sound.