Re: [announcement] the HISStools Impulse Response Toolbox

Forums > MaxMSP > [announcement] the HISStools Impulse Response Toolbox
Sep 18 2012 | 2:09 pm

Hello Alex,

Thank you for your response, it is very explicative.
Please see attached a screenshot of a simple max patch based on your irmeasure~ object where I have derived a self IR through a measurement loop in order to evaluate the results of two different behavior for the chirp:

1) Fade: the chirp has a fade-in of 0.1 ms and fade out of 15 ms
2)nofade: the chirp has fade-in of 0.1 ms and no fade-out
3) ES: this is the self IR derived in our PD software Exochirp.

My point is that it can be easily seen that both nofade and ES shows an almost perfect DIRAC in time domain while fade does not.
this is due to the effect of the fade-out filter as described by Farina in his papers.

Also there is a difference between nofade and ES in frequency domain at very high freq. (close to Nyquist) that is due to the different formulations of the chirps (all info about Expochirp can be found here:

Now the discussion I reckon shall be on the difference this does make in the real world for room correction purposes and if a difference is perceived by the user between the two different IRs.

You says: "The way we do room correction means that pre-ring (if it happens and I have not seen it in practice) is not an issue."
This is enough for me to answer my previous question but I would really love to discuss the above further and I will try to do more tests in real world cases to understand if with your method for room eq there is real difference between the 3 cases shown above.

I also agree with you that probably C74 forum is not the right place to discuss about math on this topic but I really appreciate the fact that you are willing to discuss more in detail, thank you.

Re deconvolution, I am not an expert in this and I really appreciate your offer to prepare sample patches.

I wish you a very nice day



  1. MeasuretestHIRT.png


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