Howtosignalprocessing
- Can delays cause comb filtering?
- How do you add a delay to a filter?
- What is comb filtering and how is it used to create flanging and phasing?
- How do you calculate comb filter?
Can delays cause comb filtering?
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 add a delay to a filter?
For a linear filter,1 the input and output signals are related by a transfer function H(f):(1) If H(f) is known, then the frequency-dependent delay, d(f), can be calculated:(2) d ( f ) = - 1 2 π d d f Φ ( H ( f ) ) , where Φ(H(f)) is the phase of H(f).
What is comb filtering and how is it used to create flanging and phasing?
Comb filtering creates peaks and troughs in frequency response, and is caused when signals that are identical but have phase differences — such as may result from multi-miking a drum kit — are summed. An undesirably coloured sound can result. The same effect can be harnessed deliberately to create flanging effects.
How do you calculate comb filter?
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.
