Old 01-13-2018, 12:24 PM   #1
pipelineaudio
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Default Good link to Impulse Response Explanation?

Does anyone have a good link to an explanation of how filter length affects the sound on an impulse response?
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Old 01-21-2018, 08:27 PM   #2
Philbo King
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The question appears to address two unrelated areas of sampling theory.

Filter length is an attribute of a finite impulse response filter, which affects the attainable filter slope of one type of digital filter.

The sound of an impulse response the the resulting of passing audio through a convolution process where a linear non-timevariant process (such as how a speaker responds to an impulse) is applied to the input audio.

Maybe you could clarify what you are trying to find out?
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Old 01-27-2018, 03:11 PM   #3
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Everything I can find says that too short a filter length (say the filter length knob on an IR loader or an actual IR file itself that has been trimmed too short), will cause an inaccurate bass response. Is this true? And how do you tell exactly when its too short?
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Old 01-30-2018, 10:38 PM   #4
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Oh, you are talking,about the number of samples in an IR?

The most intuitive answer is trim it at the point where the response file has returned to zero, leaving maybe a bit more, so the convolving can finish. I'm not positive; but it might be prudent to make sure the impulse lasts at least 1 period at the lowest frequency you intend to use (20 mS for 50 Hz, 40 mS for 25 Hz).

The quickest way to find out is to get an IR of, say, a bass speaker cab, then make shortened copies of it of varying lengths and see what happens. If you do, let me know what you find, I'm curious.

Last edited by Philbo King; 01-31-2018 at 03:10 AM.
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