A microphone circuit includes a first microphone, a second microphone, an
adjustable delay unit, and a combiner. The first microphone generates a
first microphone signal that includes a contribution associated with an
output signal that is generated by a loudspeaker in response to an input
signal. The second microphone generates a second microphone signal that
includes a contribution associated with the output signal from the
loudspeaker. The adjustable delay unit delays the second microphone
signal relative to the first microphone signal by a delay value. The
combiner combines the delayed second microphone signal and the first
microphone signal to provide a combined microphone signal. The adjustable
delay unit adjusts the delay value so as to reduce at least a portion of
the contribution to the combined microphone signal that is associated
with the output signal from the loudspeaker.