2
$\begingroup$

I'm wondering if there is a technique by which to analyze an existing sound recording and extract some details of the reverb and echo that are present (either due to natural environment, or added during production).

Are there software packages or libraries that implement that sort of analysis? (Is there even a chance of recovering the audio minus the reverb?)

$\endgroup$
  • 1
    $\begingroup$ Hello gwideman, can you please add some more information about your question? In general, yes, it is possible to infer a number of things from a recording with reverberation such as the size and general shape of the room. It is also possible to reverse engineer the reverb, provided that it is time invariant. What exactly are you interested in? $\endgroup$ – A_A Jan 27 '16 at 10:10
  • 1
    $\begingroup$ I'm imagining some sort of plot that shows perhaps amount of reverb versus time delay. (Analogous to FFT plot, though obviously we're not discussing frequency here.) I realize different sound sources within a recording may have different reverb, and teasing that apart might be difficult. My interest is first to understand what sorts of reverb analysis are possible and available. Then to apply those tools to segments of music recordings to learn what reverb process causes a particular subjective effect. And disentangle that from the subjective effect of an instrument's own dry sound texture. $\endgroup$ – gwideman Jan 27 '16 at 10:27
  • $\begingroup$ Hi @A_A, just like gwideman, I too am interested if it is possible to extract a "reverb profile" of the reverb of a certain room from a recording, basically doing the inverse operation of convolution reverb. If that's not possible, I would already be happy to have an algorithm that just detects if reverb exists, and maybe gives a number for the "amount" of reverb. $\endgroup$ – Konstantin Schubert Nov 18 '18 at 13:29
  • $\begingroup$ @KonstantinSchubert Please post a new question on this board. $\endgroup$ – A_A Nov 18 '18 at 21:27
  • $\begingroup$ @A_A done: dsp.stackexchange.com/questions/53559/… $\endgroup$ – Konstantin Schubert Nov 22 '18 at 22:25
1
$\begingroup$

You may be able to reverse engineer the reverb if you have a segment of relatively clean reverb 'tail'. This will allow you to play around and get some metrics such as decay time and frequency response.

Convolution reverb works by recording an impulse response in a particular location/machine after a burst of noise. This is then convolved with the input signal to apply the reverb.

| improve this answer | |
$\endgroup$
  • 1
    $\begingroup$ While it may be possible, but difficult, to iteratively hone in on an appropriate impulse I was suggesting something else. If there is a clean section of audio containing only the reverb (as there often is at the end of a piece of audio) you could create your impulse response from this and build an approximation of the reverb. It's worth noting that post-production compression (if your source is music) will have an impact on the response of the reverb. $\endgroup$ – CatsLoveJazz Jan 27 '16 at 10:50
  • 1
    $\begingroup$ From the question it doesn't look that he has either the clean signal (signal played/spoken) or the impulse response of the recording environment ? $\endgroup$ – Arpit Jain Jan 27 '16 at 11:13
  • 1
    $\begingroup$ Apologies, by clean I meant a part of the signal where only the reverb tail was audible not dry signal. $\endgroup$ – CatsLoveJazz Jan 27 '16 at 13:26
  • 1
    $\begingroup$ @arpit Right, I hoped to apply this to arbitrary recordings, not to recordings specifically created for analyzing reverb of spaces, for example, and not "clean" segments (such as tails). $\endgroup$ – gwideman Feb 9 '16 at 1:38
  • 1
    $\begingroup$ @CatsLoveJazz Thanks for your comments. I've plused up your answer and comments, but still hope someone might come along with a better answer so haven't marked this as solved. Thanks again. $\endgroup$ – gwideman Feb 9 '16 at 1:40

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.