# When do I switch from RS SPL to calibrated mic?



## pepar (May 30, 2006)

I have the calibrated mic (and pre-amp) from Acoustisoft (ETF5 and now BPlusD) and would like to use that with REW. I've read the REW help and while it mentions using a calibrated mic, it says that an SPL meter must be used initially. But it never says when (or how) to switch from RS to the mic. Nor does it say when to load the .cal file. Could somebody please give me some assistance?

TIA!


----------



## Sonnie (Apr 11, 2006)

You really wouldn't have to load the .cal file for this.

Hook up your calibrated mic and amp. Hold your SPL meter as close as possible to the mic and "Set Measurement Level" (I prefer to set it to 80 or 90db). The SPL meter is simply used to set that level initially. You are done with the SPL meter then. You would then "Set Input Level", which will make sure you have your mic amp level set properly. Then "Calibrate" the REW SPL meter to your SPL meter. You don't necessarily have to have your SPL meter for this because you have already set the measurement level to 80 or 90db, or whatever you set it at. When you "Calibrate" the REW SPL meter you will adjust the level to the same SPL level you set during "Set Measurement Level".

Now... if you take a lot of peaks out during the filter setting, when you go back to measure the filtered response you will most likely need to "Set Meaurement Level" again because you've obviously cut the overall level in most cases by taking out those peaks. It won't (or may not) be loud enough as is to get a good reading. So you'll need the SPL meter once again.


----------



## pepar (May 30, 2006)

Sonnie said:


> Hold your SPL meter as close as possible to the mic and "Set Measurement Level" (I prefer to set it to 80 or 90db).


hahahaha - that figures!



> You really wouldn't have to load the .cal file for this. Hook up your calibrated mic and amp. Hold your SPL meter as close as possible to the mic and "Set Measurement Level." The SPL meter is simply used to set that level initially. You are done with the SPL meter then. You would then "Set Input Level", which will make sure you have your mic amp level set properly. Then "Calibrate" the REW SPL meter to your SPL meter. You don't necessarily have to have your SPL meter for this because you have already set the measurement level to 80 or 90db, or whatever you set it at. When you "Calibrate" the REW SPL meter you will adjust the level to the same SPL level you set during "Set Measurement Level".


Cool. Thanks!!!



> Now... if you take a lot of peaks out during the filter setting, when you go back to measure the filtered response you will most likely need to "Set Meaurement Level" again because you've obviously cut the overall level in most cases by taking out those peaks. It won't (or may not) be loud enough as is to get a good reading. So you'll need the SPL meter once again.


I'm using a Rane PE17 for a parametric; do you have any tips for me on using REW and manually entering filters parameters into the PEQ?


----------



## brucek (Apr 11, 2006)

> I'm using a Rane PE17 for a parametric; do you have any tips for me on using REW and manually entering filters parameters into the PEQ?


I would say that the only caveat reagarding the Rane would be to select the FBQ2496 as the type of Equalizer in the pull down. This results in the filter values being given in octaves. This would be consistant with Rane that has an octave analog dial. If you select the 1100P it gives you the values in bw/60 (not what you want). The other equalizer selections are displayed in Q. You could convert, but why bother. Just use the 2496 as the type and I think it will be close.

You will have some trial and error because your dials are analog, but measuring only takes a second, so no problem...

brucek


----------



## Snookboy (Apr 28, 2006)

Sonnie,

I am having some difficulty with the mic. (I am using the ECM8000 and UB802 as per recommendation) I can't seem to set the level high enough on the UB802 to get a measurement level in REW below the max. If I turn up the level on the 802 too high, I start to get feed back on the sub. If I set the level just below where I get feed back on the sub, when I set input volume, I get the error that it is at the max. Should I be getting this feedback? Something connected incorrectly? Any and all help is greatly appreciated.


----------



## Sonnie (Apr 11, 2006)

Yeah... there is a connection or setting somewhere that isn't right. I had that same problem once and was getting that feedback and was like :duh: when I realized what I had done. The sad part about this is I can't remember what the problem was... heehee. Maybe it will come to me... or someone else will know before my memory refreshs (I keep hitting the refresh button but nothing happens :dontknow: ).


----------



## Snookboy (Apr 28, 2006)

Well, I can't think what it could be. I have the line in on the 802 connected to mic with an xlr cable and one channel of the tape out connected to the line in on the sound card. Something on the sound card? Oh well. I'll take a look and play around with it. Thanks!


----------



## pepar (May 30, 2006)

Hi Y'all, me again. I'm going to a fellow home theater enthusiast's house tonight to run some FR measurements on his subwoofer. I've read and digested - and saved as files on my "HT Measurement Laptop" just in case - this thread and all REW-related information linked here, but I seem to still be a bit unclear on when to load the CAL file for my mic. After setup and just before using the RS meter to establish a reference level, right?

TIA!


----------



## Sonnie (Apr 11, 2006)

Not sure if this is in time or not but I'm pretty confident you will get it right. You can load it at anytime after starting REW and prior to taking the measurements.


----------

