# mic position for measurement



## umbralglow (Jan 12, 2012)

HTS Forum,

I'm wanting to measure the acoustics of my studio with a Behringer omnidirectional measurement microphone. Is it best to point the mic toward the front of the room (toward speakers) or toward the ceiling to perhaps measure the entire room response?

Thanks,
Weldon

(post number one BTW)


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## tonyvdb (Sep 5, 2007)

Hi Weldon, Welcome to the Shack!

Generally pointing the mic up is the best method of measurement or at the most a 45 degree angle towards the front. The mic should be placed at ear level.


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## umbralglow (Jan 12, 2012)

Thanks for the quick reply! This looks like a great forum.

All the best,
Weldon


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## tonyvdb (Sep 5, 2007)

No problem, Enjoy your stay with us :T


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## Wayne A. Pflughaupt (Apr 13, 2006)

Whatever mic orientation you use, you’ll need the appropriate calibration file. You can’t use say, a straight-up positioning with a horizontal file.

That said, the traditional mic orientation for free-field measurements (which applies to most reasonably-dampened home or studio environments) is pointed straight at the speaker being measured. This orientation would use a 0º-incident (horizontal) calibration file. This would be for frequency-response measurements; I can’t comment on mic orientation for other acoustical measurements. And naturally, this is for the main channels; mic orientation isn’t relevant for measuring subwoofers. 

For more on mic orientation, see here, here, and here.

Regards,
Wayne


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## umbralglow (Jan 12, 2012)

Thanks for the response and the links, Wayne. I've read them and I'm sure I'll reread them during the course of my experimentation. My goal is to address some acoustical problems in my studio for the purpose of mixing multitrack recordings.

I'm using just two near-field reference monitors with a switchable sub. I won't be equalizing the sound from the monitors since their spec is already a fairly flat frequency response. My primary problem is with the acoustics of my room. Unfortunately, I don't have control over the construction and dimensions, so I'll have to make use of bass traps, diffusers, etc. to help to correct a problem with room modes.

My plan is to take acoustical measurements with an ECM8000 using a 0-degree calibration file at various locations within the listening sweet spot with the goal of minimizing the problems I am encountering. I think I'll make a set of measurements with the mic on axis toward the monitors and then another set of measurements with the mic in a vertical orientation. A comparison of the two sets, before and after treatment, should yield some indication as to whether or not I am improving my situation.

Maybe my thinking is off base. If it is, I would appreciate any more thoughts on the matter.

Thanks,
Weldon


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## Wayne A. Pflughaupt (Apr 13, 2006)

The waterfall graph is good for gauging any improvements in modes that traps would bring – i.e. reduced severity in the peaks and troughs and shorter low frequency decay times. Standard unsmoothed frequency response graphs can show general improvements that absorptive treatments would make, by displaying less comb filtering in the upper frequencies compared to before-treatment. However, there are other acoustics measurements that might be better in this regard, such as ETC. We have a guy here who goes by the handle SAC who’s knowledgeable about measurements like that; you might try looking up some of his posts.

Regards,
Wayne


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## umbralglow (Jan 12, 2012)

Thanks, Wayne, I'll check some of his posts. I spent some time yesterday getting my audio interface calibrated. My Firewire interface won't work with REW, so I went with an old M-Audio FastTrack Pro USB interface that works fine. I don't know if the Firewire issue is specific to a Mac, but I read in some post, somewhere, that it had presented a problem to another Mac user.

Best,
Weldon


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