[cavchameleon]

Anechoic,

Received my calibrated ECM8000 today. Thanks a lot for such quick service!!!

Ray

 

[Sonic Icons]

Hi,

First, I would like to thank you (Anechoic) for helping this forum with your calibration services and technical insights. I have a question about the "generic" Behringer ECM-8000 calibration file on the Downloads page, with filename "ECM8000-CS.cal". Is this file based on an average of measurements of ECM-8000's done in your lab? To me, the "generic" calibration file looks flatter in the bass than I would have guessed from the range of response curves you showed in message #43. The "generic" file has -1.40 dB at 20 Hz, -0.54 dB at 25 Hz, while the curves in message #43 appear to range from -5.5 dB to +1 dB at 20 Hz, and from -4 dB to +1 dB at 25 Hz.

 

[brucek]

I have a question about the "generic" Behringer ECM-8000 calibration file on the Downloads page, with filename "ECM8000-CS.cal". Is this file based on an average of measurements of ECM-8000's done in your lab?

No, Cross Spectrum does not load the files on our download page.

The ECM8000 generic calibration file is from Sonnie's personal ECM microphone that Cross Spectrum calibrated for him.

Of the calibrations that were carried out on this microphone, we chose the Frontal incident (horizontal on-axis 0 degrees), 1/6th octave spacing file and reduced it to two decimal places. It should be fine for home use.

If you require more accuracy, it's best to get your own microphone calibrated.

brucek

 

[Sonic Icons]

Thank you for the clarification - the "generic" ECM-8000 calibration file on the downloads page is clearly within range of the response curves shown in #43, if it is understood to be the curve for one particular microphone, rather than an average of all the ECM-8000s tested by Cross-Spectrum.

I agree that the data (the variation of the curves in #43) shows that individual calibration is needed for accurate measurements. Also, it is noteworthy that there is a lot of variation in the deep bass (20 - 100 Hz) (the critical frequency range for measuring subwoofer room response), as well as the highs (5 - 20 kHz).

 

[cavchameleon]

Thank you for the clarification - the "generic" ECM-8000 calibration file on the downloads page is clearly within range of the response curves shown in #43, if it is understood to be the curve for one particular microphone, rather than an average of all the ECM-8000s tested by Cross-Spectrum.

I agree that the data (the variation of the curves in #43) shows that individual calibration is needed for accurate measurements. Also, it is noteworthy that there is a lot of variation in the deep bass (20 - 100 Hz) (the critical frequency range for measuring subwoofer room response), as well as the highs (5 - 20 kHz).

Yep, as brueck mentioned, it's pretty much fine for the home user, but if you want accuracy, go ahead and get a calibrated one from Cross Spectrum (you'll get it within a couple days of ordering). He has the best price for a calibrated ECM-8000 (there are many mics out there that you can purchase that are calibrated, most being several times the cost of the Behringer, and for most, not necessary.

Ray

 

[Sonnie]

To confirm... we have no issues with Herb quoting prices here at the Shack if he so desires. :T

 

[cavchameleon]

Sonnie,
I didn't know if I would be able to quote the price. Since I just purchased it from Herb, here is some info.

Sonic Icons,
Here is Herb's site:
http://www.cross-spectrum.com/measurement/calibrated_behringer.html
You have a choice of to levels of calibration:
1 - Freq response only ($85)
2 - Freq response and Polar Data ($100)

His site has a lot of useful info if you have not checked it out already.

Ray

 

[JohnM]

As an aside to all this, with REW V5 the cal data can (ideally should) include phase as well as SPL correction, so should look at including phase data from calibration.

 

[lcaillo]

If we were going to do so, would it not make sense to calibrate the mic/preamp as a system, since there may be more phase effect in the combination than just in the mic?

 

[VintageGold]

I see you also calibrate the Galaxy CM-140, but along with selling pre-calibrated ECM8000, do you also sell pre-calibrated CM-140's? I'm planning on picking up a CM-140 but wanted to find out if these are available before I purchase from some where like Musician's Friend.

 

[Anechoic]

A couple of things:

1. If you ask me a question here and I don't respond within 24-hours, shoot me an email directly and I'll respond here. For some reason I don't always get the thread update emails.

2. Here's a head's up - I offered to do freq-response curves at additional angles for my calibrated mics for free. However, it's become a bit of a hassle to keep track of the various special orders. As a result, I'm going to change things a bit - as of August, I'm going to offer 4 mic models: a) "Basic" with 0-deg freq response for $85, b) "Basic-Plus" with 0/45/90 deg for $90, c) "Extra" with 0-deg freq response, polar, noise floor, and sensitivity for $100 and d) "Extra-Plus" with the "Extra" package + 0/45/90 deg for $110. On the plus side, I'm going to do freq-response down to 5 Hz by default.

This is going to be a price increase but on the plus side, I'll try to stock up on these models so there won't be a wait for people who want the 45/90-deg measurements.

However, I will still do the extra measurements for free for orders placed before Aug 1, so if you want to save some money, place your order before then.

Now on to questions:

If we were going to do so, would it not make sense to calibrate the mic/preamp as a system, since there may be more phase effect in the combination than just in the mic?

For my measurements, it doesn't matter since I don't measure phase .

I see you also calibrate the Galaxy CM-140, but along with selling pre-calibrated ECM8000, do you also sell pre-calibrated CM-140's?

I don't sell pre-calibrated meters and I don't imagine I ever will because there are potential liability issues on my end if people purchase it from me for the purpose of using it in a legal setting. However, if you buy a meter, you can have it shipped directly to me, and I'll calibrate it and send it on to you which should at least save a couple of bucks in shipping costs as well as a couple of days of time.

 

[Dennis H]

as of August, I'm going to offer 4 mic models: a) "Basic" with 0-deg freq response for $85, b) "Basic-Plus" with 0/45/90 deg for $90, c) "Extra" with 0-deg freq response, polar, noise floor, and sensitivity for $100 and d) "Extra-Plus" with the "Extra" package + 0/45/90 deg for $110. On the plus side, I'm going to do freq-response down to 5 Hz by default.

Do the Basic and Basic-Plus not include 1K sensitivity? Seems like everyone would need that.

 

[Anechoic]

Do the Basic and Basic-Plus not include 1K sensitivity? Seems like everyone would need that.

Correct, the Basic and Basic-plus do not include 1 kHz sensitivity. I thought more people would want sensitivity but it turns out that very few people care about - in fact more people want the polar response than the sensitivity.

 

[Dennis H]

Correct, the Basic and Basic-plus do not include 1 kHz sensitivity. I thought more people would want sensitivity but it turns out that very few people care about - in fact more people want the polar response than the sensitivity.

That's amazing. How are they measuring SPL? An RS meter that may or may not be within 3dB?

On another subject, can you calibrate above 24K for an extra charge? Many people are using 96K sound cards with a nominal 48K capability so it would be nice to have a general idea what the mic is doing up there, even if the calibration isn't perfect.

 

[Anechoic]

Are people using the ECM8000 to measure SPL? I assumed most people were just using them for freq response curves.

The problem with >24kHz measurements is that I don't have calibration curves for my reference mics that go that high. The next time I send in my ref mic for calibration I'll ask them to push the curve out to 40+kHz and then maybe I'll offer the service for an extra charge.

 

[Dennis H]

ARTA (along with some other programs, don't know about REW) has a setup routine where you calibrate your mic preamp and sound card with tones and a voltmeter so you can do your measurements in dB SPL if you can plug in the mic's sensitivity.

 

[Sonnie]

That's amazing. How are they measuring SPL? An RS meter that may or may not be within 3dB?

Are people using the ECM8000 to measure SPL?

Some will use the RS meter, some the Galaxy CM-140 and others the ECM8000. SPL is not that terribly important. For level matching, most receivers and processors have Audyssey or equivalent for setting up the system anyway. :nerd:

If you wanna just see how loud it will get, for whatever that may be worth, getting within 3db should be plenty sufficient, unless someone really has an OCB about being the SPL king, like the kids in the car stereo crank off contests. :dumbcrazy:

 

[Anechoic]

I know that you can do SPL measurements with the ECM8000 (I am an ARTA user & FWIW a Type 1 mic + ARTA gets you the same results as a Type 1 meter) I was just curious if anyone is actually doing it.

Some will use the RS meter, some the Galaxy CM-140 and others the ECM8000. SPL is not that terribly important. For level matching, most receivers and processors have Audyssey or equivalent for setting up the system anyway. :nerd:

which sounds about right.

The reason I do sensitivity measurements is so people can do measurements but no one (outside of pros) really seemed to care. Interesting...

 

[cavchameleon]

Interesting...
I use a calibrated meter for SPL (well, use to, but just let Audyssey do that adjustment now - sometimes comfirm with the meter, but really not necessary). For SPL, it is MUCH easier to just use a calibrated meter then a calibrated mic with computer/software (no setup time) IMO. As Sonnie mentioned, there are 'some' that want to know max spl (I prefer to keep my hearing). I have use my meter just out of curiosity to see where my dynamic peaks are hitting with normal dialog at 85db (meter showed 109db on peaks), but only because I wanted confirmation that peak levels do not sustain long enough for hearing damage.

Ray

 

[Dennis H]

The crowd where I usually hang out is into designing speakers so having the levels calibrated is useful when you're mixing and matching drivers that may have been measured at different times and under different conditions. The most common way is to normalize everything to 2.83V/1m when you save the files.