Another Room Response Question

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doncolga
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2008/05/23 10:04:44 (permalink)

Another Room Response Question

Monday night I measured room response and was super happy with the results. For the heck of it, I measured last night and it was different...and I was LESS happy.

Have any of you observed that before?

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    bitflipper
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    RE: Another Room Response Question 2008/05/23 12:11:37 (permalink)
    Unless you have exactly the same setup each time, you'll get inconsistent measurements. Just moving the mic a couple of inches will alter the results, as Ethan Winer demonstrates dramatically in his video on comb filtering, where he moves a mic around the room while monitoring what it's picking up.

    In a small room, your own body is a major acoustic variable, so it's best if you leave the room when you take measurements.

    But even though the absolute levels will vary, the problem frequencies will remain constant. The important thing is not the absolute levels but identifying the particular frequencies that are a problem. Even a very well-treated room will still have measurable peaks and valleys, so you'll never completely flatten the curve. All you can do is identify the problem frequencies and look for improvement as you add absorption.



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    doncolga
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    RE: Another Room Response Question 2008/05/23 12:29:26 (permalink)
    OK...my obsessive compulsive side is SO totally kicking in. Damn.....I was thinking of all the different things it could be...air pressure, humidity, temperature, lighting...

    I can come to terms with that though. I'm being way too nit picky. I'm still getting generally good response...and as you said, the BIG problems that I had before seem to be tamed pretty darn well. But man...my last measurement on Monday was just really, really good.

    Maybe I should tape the measurement mic to my head and sit in the mix position, eat all the same foods that day, wear the exact same clothes...

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    droddey
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    RE: Another Room Response Question 2008/05/23 13:26:49 (permalink)
    I think that the better you get the room tunes, the less the mic movement will be a problem, i.e. the 'sweet spot' gets larger because there's far less sound pressure complexity at the listening environment by then. Much less low frequency energy is getting back to the listening position. If the room is really bad, and in any areas other tahn the listen position you are optimizing, you can definitely get huge swings a foot apart at given frequencies. My room, at the listening position, is good enough now that the sweet spoot seems to be a few feet left to right and up and down from the listening position. It's less so front to back because you are so close to near fields that just moving forward a bit really reduces your distance from them by a large position. It is fairly large moving backwards.

    Though, having said all that, you do want to make sure the mic is at your head position exactly.
    post edited by droddey - 2008/05/23 13:49:51

    Dean Roddey
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    www.charmedquark.com
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