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edvinpedvin
Level 1 (15 points)

Q: IR - reponse curves, visual representation

Hi guys,

I'd like to try out the IR utility in our video studio, before and after some acoustic dampening of the room.

What I'd like to see, is some visual representation of the room response.
Is this possible/any good with IR utility? Will the deconvolved return signal suffice as a frequency response curve for the room? What about phase response?

I have never used the utility, but just printed the user guide (42p).
Browsing it, I find no info in this regard.

Cheers + thanks for any (constructive) feedback

Eivind

MacPro 8-core, Mac OS X (10.5.8), Macbook 2GHz at home

Posted on Oct 13, 2009 2:02 AM

by John Buehler,Solvedanswer
John Buehler John Buehler
Level 2 (385 points)
A:
You will either need to do a T.E.F, or find a copy of Spectrafoo Complete (not gonna be easy, it's only power pc, I actually have a G5 dedicated to just running Spectrafoo). T.E.F. stand for time, energy, and frequency, and you will need an Audio Precision, which is not cheap. And a flat mic like an earthworks doesn't hurt either.

Spectrafoo is great because it shows the difference between phase cancellation versus spectral non-linearity. Boosting 100 hZ does no good if it's out of phase.

Posted on Oct 13, 2009 1:54 PM

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edvinpedvin

Q: IR - reponse curves, visual representation

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  • Helpful answers

  • by John Buehler,Helpful

    John Buehler John Buehler Oct 13, 2009 1:48 PM in response to edvinpedvin
    Level 2 (385 points)
    Oct 13, 2009 1:48 PM in response to edvinpedvin
    Well, I know exactly what you are talking about, and the answer is that the IRU is useless for showing you anything about your room. If you want to compare the spectral changes, you could use the Match EQ to compare the difference between before and after. But the IRU is of no use visually.

  • by John Buehler,Solvedanswer

    John Buehler John Buehler Oct 13, 2009 1:54 PM in response to edvinpedvin
    Level 2 (385 points)
    Oct 13, 2009 1:54 PM in response to edvinpedvin
    You will either need to do a T.E.F, or find a copy of Spectrafoo Complete (not gonna be easy, it's only power pc, I actually have a G5 dedicated to just running Spectrafoo). T.E.F. stand for time, energy, and frequency, and you will need an Audio Precision, which is not cheap. And a flat mic like an earthworks doesn't hurt either.

    Spectrafoo is great because it shows the difference between phase cancellation versus spectral non-linearity. Boosting 100 hZ does no good if it's out of phase.

  • by edvinpedvin,

    edvinpedvin edvinpedvin Oct 14, 2009 11:18 AM in response to John Buehler
    Level 1 (15 points)
    Oct 14, 2009 11:18 AM in response to John Buehler
    Hi JOhn,
    thanks for the reply.

    I realized IRU was useless for this, but maybe Match EQ on the before and after recorded reponses will tell us anything.

    If I could dump the raw sine sweep to file (for example with wiretap pro), MatLab could also do the math. But Matlab is not free, either

    I guess I'll just go for Match EQ. I'm just curious, and want some indication, don't need a thorough analysis for this.

    Cheers!