Howtosignalprocessing
- What is the comb filter effect?
- How do you calculate comb filtering?
- What can cause comb filtering to occur?
- How do you reduce comb filtering?
What is the comb filter effect?
Comb filtering is a phenomenon that happens when the same sound arrives at the listener's ears (or a microphone) at different times with a very small delay between the signals. This delay can be anywhere from one sample to several milliseconds, up to 15ms–20ms.
How do you calculate comb filtering?
The fundamental frequency of a comb filter is the inverse of the delay time. That is, the frequency of the first peak in a comb filter (constructive interference) is equal to 1 divided by the difference in arrival time between the microphones (the delay time), in seconds.
What can cause comb filtering to occur?
Comb Filtering caused by Sound Reflections
As reflected sounds travel a further distance than the direct sound, they arrive at our ears or at a microphone later. Both signals are identical, but one signal is delayed by a few milliseconds, causing a comb filter, where some frequencies are cancelled and some are summed.
How do you reduce comb filtering?
It is possible to reduce the effect of comb filtering by applying a compensating delay to one of the microphone signals to give the impression the source is arriving at each microphone at the same time.
