DIY Room Testing Mics

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peritus

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Would either of these mics be superior to my Rode NT1000 and Rode NT1A testing room acoustics? I'm read that an omni is required (and I ain't got one yet)... Thoughts? Suggestions?

Thanks! :)
 
peritus said:
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Link 2

Would either of these mics be superior to my Rode NT1000 and Rode NT1A testing room acoustics? I'm read that an omni is required (and I ain't got one yet)... Thoughts? Suggestions?

Thanks! :)

Yes, the Rodes will not be accurate for room testing. One of those designs is much more likely to be appropriate, but if you build it yourself, you have no way of knowing the response of the mic.

The Behri ECM8000, or its twin, the Apex 220 (which I have) are about $50, and at least my Apex came with its own measured response curve.
 
Sound like exactly what I need... Is there one of the two that you prefer? Any other pointers on the subject of room measurement?

Thanks!
 
peritus said:
Sound like exactly what I need... Is there one of the two that you prefer? Any other pointers on the subject of room measurement?

Thanks!

I like the Apex, because it's black and not Behringer ;) But other than the paint, I think they are identical.
 
it would be very helpful to have a frequency response graph with your mic. That way you can compare the frequencies you collect with the mic's personal response. subtract the mic's response from your measurements and you'll get the actual response of your room.

my superlux ECM-999 came with an individual (serial numbered) freq. response. but it runs around $140.
 
Cool. Thanks!... That last suggestion looks good and makes good sense but I think it might be overkill for my purposes.

Mshilarious, can you verify that the ECM8000 doesn't come with a serialed frequency curve please?

Looks like I can buy the ECM8000 locally (i.e. today) for $50 @ Parts Express.

Here's what I'll most likely use for my measuring tests (to get started).
Allen-Heath RTA 14 Day Demo

Thanks again!
 
peritus said:
Cool. Thanks!... That last suggestion looks good and makes good sense but I think it might be overkill for my purposes.

Mshilarious, can you verify that the ECM8000 doesn't come with a serialed frequency curve please?

No, I don't know if it does or not.

Say hi for me at PartsX! One of my favorite vendors :)
 
I have 2 of the Behringers and they did not come with a frequency curve.

I think the Nady CM100 Reference Measurement is the same mic for $39.99 at Musiciansfriend.
 
Thanks for the info...

Well I picked up the Behringer mic... I'll let ya know how it all works out...
 
Okay... After fumbling with this thing for a while... I can be honest....

I'm kinda lost... Hmm... Maybe sleepin' on it'll help... Argh!
 
peritus said:
Okay... After fumbling with this thing for a while... I can be honest....

I'm kinda lost... Hmm... Maybe sleepin' on it'll help... Argh!

OK, you need two other things: pink noise, and some RTA software. There is freeware out there if you need it. I seem to recall the Allen & Heath site had one. It also helps to have an SPL meter. If you do, play the pink noise through your monitors and calibrate them to 85dBSPL C-weighted.

Next, close mic one of your monitors and perform an RTA on your monitors. This will give you a baseline for your room, since you have to control for your monitors.

Finally, place the measurement mic at your mix position. For a tracking room, also test various places where you would normally setup mics. Normalize the results and compare with the close-mic RTA graph.

Pay special attention to the bass frequencies. You need to set the RTA program to analyze at a fairly fine resolution. I use a little less than 1Hz between points in the bass region.

You should have results that tell you what nodes you have, where they are, and how bad they are. You can then take steps to mitigate the issues. You will also have learned something about the performance of your monitors.
 
Thanks for the input... I hope to try some more on this during my weekend...

Which illogically begins on Wednesday morning and ends Saturday night.. :(

I am re-re-reading the Ethan Winer manifesto before venturing into the topic full force again... Alll 'n all, l am learning a lot here so far... :D
 
mshilarious said:
OK, you need two other things: pink noise, and some RTA software. There is freeware out there if you need it. I seem to recall the Allen & Heath site had one. It also helps to have an SPL meter. If you do, play the pink noise through your monitors and calibrate them to 85dBSPL C-weighted.

Next, close mic one of your monitors and perform an RTA on your monitors. This will give you a baseline for your room, since you have to control for your monitors.

Finally, place the measurement mic at your mix position. For a tracking room, also test various places where you would normally setup mics. Normalize the results and compare with the close-mic RTA graph.

Pay special attention to the bass frequencies. You need to set the RTA program to analyze at a fairly fine resolution. I use a little less than 1Hz between points in the bass region.

You should have results that tell you what nodes you have, where they are, and how bad they are. You can then take steps to mitigate the issues. You will also have learned something about the performance of your monitors.

I just finished doing this. I bought an Earthworks TC20 for about $375. I needed the mic anyway, so I thought I would check out my room. I did not close-mic the monitors. I should. I put the mic in the sweet spot where i sit (that does not sound right at all :eek: ). I had to record the signal, then play it back while looking at my Voxengo spectrum analyzer software. I did learn a lot about what I'm hearing and where the problem spots are. The room was actually flatter than I thought, but my monitors are a bit bass shy. Just for the heck of it, I made an EQ preset in Gliss EQ that flattens out the problems. I don't mix with it, but I do put it on the master buss when I'm finished to listen for problems. It has made my mixes translate better, for sure.

That Beringher mic does not look flat enough to test your room, but maybe I'm wrong.
 
leddy said:
That Beringher mic does not look flat enough to test your room, but maybe I'm wrong.

The small high end boost is really not a big deal. Room problems are low frequency; a wavelength at 10kHz is a mere inch or so.

My Apex 220's measured chart is pretty close to the published Behri curve.
 
mshilarious said:
The small high end boost is really not a big deal. Room problems are low frequency; a wavelength at 10kHz is a mere inch or so.

My Apex 220's measured chart is pretty close to the published Behri curve.

:eek: I was gettin' scared for a moment.. hehe
 
mshilarious said:
It also helps to have an SPL meter. If you do, play the pink noise through your monitors and calibrate them to 85dBSPL C-weighted.

I'm just wondering how important this step is. I don't want to do this wrong (In doing so, I would be wasting the money I spent on the measurement mic)... If I must have one, would this one be sufficient?


Also, should I be testing the speaker (SPL and response) in a controlled environment (say, a walk in closet, maybe)?

Thanks for your help people! I hope to post some curves soon....

P.S. I just got done reading that Ethan uses AcoustiSoft software for this purpose... I'm not able to download it at work, is anyone familiar with the demo version and its capabilities? http://acoustisoft.com/download.html
 
peritus said:
I'm just wondering how important this step is. I don't want to do this wrong (In doing so, I would be wasting the money I spent on the measurement mic)... If I must have one, would this one be sufficient?

Yes that is fine. The SPL meter is more for setting the proper monitoring level than room calibration. While you are testing your room, might as well calibrate levels through the whole system, which incudes your ears. The 85dBSPL reading should be at your mix position.


Also, should I be testing the speaker (SPL and response) in a controlled environment (say, a walk in closet, maybe)?

No. A walk-in closet is not a controlled environment. If you had an anechoic chamber, you would test your monitors' response in there, but you don't, so close-micing in your studio is close enough.
 
mshilarious said:
Yes that is fine. The SPL meter is more for setting the proper monitoring level than room calibration. While you are testing your room, might as well calibrate levels through the whole system, which incudes your ears. The 85dBSPL reading should be at your mix position.




No. A walk-in closet is not a controlled environment. If you had an anechoic chamber, you would test your monitors' response in there, but you don't, so close-micing in your studio is close enough.


Good deal... Thanks for clearing that up....
 
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