# calibrated EMC8000



## PoorSignal (Jul 23, 2009)

Just received my EMC8000 with premium+ calibration, can someone tell me how to enter this mic into REW

Thanks!


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

There should be a pdf file on the included mini CD disc titled “Read me” that has instructions. 

Typically you will want to use the *narrow band* response files. Files are provided for orienting the mic at 0, 45 or 90 degrees in relation to the speakers. I.e., 0 degrees would be used for pointing the mic directly at the speaker, etc.

Save the files to your REW folder, then open the folder and change the extensions to .CAL. In REW, click the “Settings” icon, then the “Mic/Meter” tab. From there the “Browse” icon will let you select the calibration file you want to use.

Regards,
Wayne


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## PoorSignal (Jul 23, 2009)

OK, using 90 degree because pointing up.

Do I check the C weight option in the REW?

Do I use the sponge cover on the mic?


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

PoorSignal said:


> Do I check the C weight option in the REW?
> 
> Do I use the sponge cover on the mic?


No and no. 

Regards,
Wayne


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## PoorSignal (Jul 23, 2009)

is it really necessary to use only right output of the soundcard and split that into 2 identical signals, or can the L R output of sound card go into my receiver? I couldn't find my RCA mono splitter right now.

I don't think it makes much difference?


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

Hard to say, knowing nothing about your sound card or system, or what you intend to measure. If you're only going to measure the sub, it's a mono output from your receiver, so only one input is needed. If your sound card has a pan control that takes the input and sends it to both outputs, then no splitter is needed.

Regards,
Wayne


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## PoorSignal (Jul 23, 2009)

Thanks. here is the back to back test of 2 mics!.

RS SPL with the generic calibration Weight-C (BLUE)
vs 
ECM8000 with 90 degree calibration file (RED)


I like the RS graph better 

Got another question, to adjust the ECM mic level to REW, which knob do I turn on the 802 mixer?
Is it the white one or the one closer to the mic?


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

PoorSignal said:


> Thanks. here is the back to back test of 2 mics!.
> 
> RS SPL with the generic calibration Weight-C (BLUE)
> vs
> ...


Yeah, but considering that the ECM has had custom calibration, which do you think is more accurate? :bigsmile:




> Got another question, to adjust the ECM mic level to REW, which knob do I turn on the 802 mixer?
> Is it the white one or the one closer to the mic?


Both will affect the signal level going to REW.

Regards,
Wayne


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

By the way, the ECM is an omnidirectional mic, so for measuring subwoofers, the mic orientation or calibration for 0, 40, or 90 degees doesn't matter. That only comes into play above ~4khz. IOW, for subwoofers any mic orientation is fine with any calibration file.

Regards,
Wayne


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## PoorSignal (Jul 23, 2009)

I did a sweep up to 2000hz, it has a lot of null down to 0 db on frequency above 200. Is that expected from an untreated room or is there some problem with my measureing gear? The whole thing got really jagged after the subwoofer measurements.


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## PoorSignal (Jul 23, 2009)

Also, on the mixer only the first green LED light lit during sweep and maybe the 2nd one. Does it need to be adjusted to get more LEDs (3?) lit? 

Everything is too loud as it is and I am have to turn the soundcard line in about 1/2 way down.


I think I need to calibrate the db levels, how to get the signal down to around 75db? Do you turn down the receiver? or turn down the input gain on the soundcard?


Thanks


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## glaufman (Nov 25, 2007)

PoorSignal said:


> I did a sweep up to 2000hz, it has a lot of null down to 0 db on frequency above 200. Is that expected from an untreated room or is there some problem with my measureing gear? The whole thing got really jagged after the subwoofer measurements.


Yes, that sounds like it could be the phenomenon called comb filtering... do the dips start out every X Hz or so, and then as you get up in frequency because each frequency is displayed closer and closer togther the dips combine into a mis-mash? That's absolutely typical of an untreated room, and even many treated rooms too (you don't want to know what the room will have to look like to eliminate that altogether). With full range scans, we're looking mainly to see the overall trend of the line, so you can apply 1/3octave smoothing to the plot to eliminate some of that "noise" and get a better idea of what's going on.


PoorSignal said:


> Also, on the mixer only the first green LED light lit during sweep and maybe the 2nd one. Does it need to be adjusted to get more LEDs (3?) lit?
> 
> Everything is too loud as it is and I am have to turn the soundcard line in about 1/2 way down.
> 
> ...


I don't remember what LEDs on my mixer ever looked like. I don't think I paid much attention to them. 
You run the Calibrate SPL routine in REW... while the noise is playing, adjust the volume on the AVR so the noise reads 75dB at your listening/mic position, and tell REW the signal it's getting is 75dB.


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## PoorSignal (Jul 23, 2009)

So I ended up turning the receiver down, from -22db to -30db, so that it says 75db on the radio shack SPL, and hit the calibrate button.

Then the graph is a bit different than the one I have taken up there at 85db.
The test is rather quiet now.. but maybe that is the way it should be?
Is that normal?


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## PoorSignal (Jul 23, 2009)

Here is the sweep to 10k with filter applied, I have no idea why the volume from the mains is rather low on average. With individual test tone I calibrated each speaker level to about the same db with my RS SPL.

I wasnt trying to EQ a house curve or anything here yet, this is my default receiver setting I have been watching movies with.


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## glaufman (Nov 25, 2007)

Try reposting that with a vertical scale from 45 to 105dB. I don't really think it's all that different, the level is a bit lower, that's to be expected, and it covers a much wider frequency range.

Do you have a soundcard calibration loaded?

When you calibrated each speaker, was that with the SPL meter or with REW? Were you using the internal test tones on your AVR?


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## PoorSignal (Jul 23, 2009)

Here it is

I was using receiver test tone, played at reference level and adjusted until they were all the same with RS SPL meter only.

Should I redo the speaker levels using the REW and the ECM8000? How exactly?

When doing the sweep measurement level is at -12 (dB FS), is that OK?

Sorry for all the questions, still trying to figure this out, I read alot already but everyone do this a little different.


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## PoorSignal (Jul 23, 2009)

Here is showing my mic and soundcard calibration..

soundcard calibration using a dual end 1/8" stereo jack line in and line out.

Looks like sound card has fairly flat response.


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## PoorSignal (Jul 23, 2009)

I tilted the mic about 10 degrees forward from vertical something I read from another thread

tilted = purple
vertical = green

Yikes, that affects reading a little bit.. I guess I can't really rely on any graph an absolute reference I am probably not going to EQ the mains, but might do some treatment to see how it affects the graph


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## glaufman (Nov 25, 2007)

What level of smoothing are you applying?
These graphs do show your sub running hotter than the mains... whether or not you want them better balanced is a matter of preference, so do, some want the sub running hotter. 
I'm more curious about the variations in the midrange. Scan each main speaker by itself. I find it interesting that I think there's another thread by another person with a problem in a similar range.


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

> I tilted the mic about 10 degrees forward from vertical something I read from another thread
> 
> tilted = purple
> vertical = green
> ...


 The mic is omnidirectional below ~4 kHz and exhibits increasing directivity or directionality (or whichever word is technically correct) above 4 kHz. As Greg alludes, there must be some explanation for the variations you’re seeing below 4 kHz.

Also, why are you stopping your measurements at 10 kHz?

Regards,
Wayne


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## PoorSignal (Jul 23, 2009)

Smoothing is 1/3 octave from the menu, based on your recommendation, I saw someone do 1/6 octave smooth but I don't see this option.


Now that I have a db number (in the record button) in REW with ECM8000,
should I have the receiver play test tone again and adjust each speaker's volume based on the reading in REW? That should be better than using the RS SPL which jumps around.

I suppose since I adjusted the sub level based on my RS meter, it made the meter heavily jumping around and I took a guess, I could have set it too hot to begin with, however this level may be useful when I set the house curve.

I have tried up to 12k but after the sweep, I heard a funny blip of sound each time I wonder what that is.
The high pitch was getting uncomfortable for me so I stopped at 10k. I can go up to 20k without worrying about anything?

Is the peak at 600hz some kind of room mode, I think it could be EQ'd out and maybe the dips next to it might go away also.. I have adjustable PEQ on each speaker in the receiver setting, all presets band they are available, 500, 630, 794hz. Testing the left and right alone would be a good idea.


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## glaufman (Nov 25, 2007)

PoorSignal said:


> Now that I have a db number (in the record button) in REW with ECM8000,
> should I have the receiver play test tone again and adjust each speaker's volume based on the reading in REW? That should be better than using the RS SPL which jumps around.


You may find REWs meter moves also. Did you have the RS set to "slow?" If you wanted to achieve as good as you can get balance between the two, consider running a series of scans and tweaking the level between each one based on what you see, untill you can't tell the difference...


> Is the peak at 600hz some kind of room mode, I think it could be EQ'd out and maybe the dips next to it might go away also.. I have adjustable PEQ on each speaker in the receiver setting, all presets band they are available, 500, 630, 794hz. Testing the left and right alone would be a good idea.


I doubt you would see a mode that high up without seeing evidence of it lower down, but I suppose it's possible. Where are those PEQs set? Can they be defeated?


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## PoorSignal (Jul 23, 2009)

My receiver has the PEQ but I am not using it right now, (FLAT)

it's has auto EQ like audessy but the yamaha version, I didn't use this yet, but I could go and mess with the PEQ parameters if I wanted.
.


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## glaufman (Nov 25, 2007)

If it was my system, I'd rather see the individual scans first.


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