Note: article incomplete, I need to tidy up the graphs and clarify what the lines are. I recently purchased a calibrated USB measurement microphone to help with speaker tuning. I already have a, but the Behringer isn’t calibrated, while the MiniDSP comes with a calibration file, you just download from their site keyed on the serial number of your unit. As you can see, the two units come in similar, but not the same packaging, and also look quite similar: I had been using the “generic” ECM-8000 calibration curve, but there is a fair bit of info out there that there is So why not try and calibrate the ECM-8000 using an already calibrated Mic? I know there will be inherent loss of precision during the process, but the result may still be more accurate than the generic file. Equipment used: Laptop with Homimpulse Behringer Xenyx 1204FX Mixer Behringer UCA-202 USB interface old Windows XP laptop Homimpulse 1.4.2.0 for measurement Sound source is my “under construction” active stereo speakers with the Behringer UCA-202 connected via SPDIF output.

The microphones place in a mic stand about 1M from the speakers. I’m not actually concerned too about the response of the speakers now, just that the measurements remained consistant between holmimpulse runs, which they did. Stage 1: As a sanity test I’ll calibrate the Microphone against itself. If I can generate something resembling the calibration curve by comparing measurements with and without the calibration file applied, I should be in the right ballpark. Here are the homimpulse measurements with and without the calibration file, smoothed to 5 per octave to make the differences easier to see: Here is the “no calibration” measurement, divided by calibrated – using the Holmimpulse frequency domain manipulation functions. Turns out division (uncalibrated / calibrated) gave me the curve back.

I used the raw response (no smoothing or gating) data as the source of the calculation, then smothed to 20 for visibility, phase displayed just to show mostly flat. This is superimposed on the actual calibration curve supplied by miniDSP.

Reference microphone, Behringer ECM-80006. Data and save the calibration data as a text (ASCII) file to your choice of file name with a.txt extension.

To line them up exactly I had to add 2.8 dB to the calculated cuve. From this I can be fairly sure the method I’m about to use with the Behringer ECM-8000 will give me a usable calibration curve.

Stage 2: Calibrate the ECM-8000 For this I measured the ECM-8000 the same way, through the Behringer mixer and USB sound card. I’m not concerned that much about lining up the dB magnitude as it’s arbitrary due to the level settings on the mixer (chosen to have decent headroom without clipping), so this is only a relative frequency response calibration, not an absolute dB sound level. Below is the ECM-8000 measurement, smoothed for readability to 5/octave, and superimposed on the uncalibrated UMIK-1 measurement. The ECM8000 measurement has also been reduced by 6dB to line up closely with the UMIK measurement for comparison. They are quite close. Calculated ECM-8000 calibration curve (red).

It has been offset by -6.5 to line up with 0dB, and the UMIK-1 calibration file and generic ecm-8000 calibration file are also shown (blue and green). Smoothed to 20, although the imported calibration curves obviously are even smoother. With Holmimpulse I can export as a calibration file. The file exported is 1997 lines compared to the 560 lines of the UMIK-1 calibration file, so possibly overly detailed compared to the source data – but using this calibration file with Holmimpulse, I do a frequency response sweep and compare against that done with the UMIK-1: And the calibrated/uncalibrated curves are quite close. With the UMIK-1 curve a bit different.

So I can conclude this method probably not too useful, although the results look good. This entry was posted in. Bookmark the.

You can also use your own omnidirectional measurement microphone with a calibration. To do so, you will need to convert your calibration file so our measurement software can import it. Calibration files are usually supplied in formats like.cal or.txt Open up this file with any text editor and remove anything that is not the values for Frequency Response and Magnitude. You also don't need any title, description and ending texts in your file, so make sure they are deleted. Once there are only the values for FR and Magnitude left, save this file as a.txt file and our measurement software will be able to read it. Text file before editing: Text file after editing.

So I've finally gotten Room EQ Wizard to work. Basically, I had to switch computers.

The first one I tried, the one conveniently located of course, has on-board Nvidia audio. While having line in/out, I simply couldn't get it to work with REW. Thus, I had to lug my computer down from upstairs. It has on-board Creative Audigy sound, and it seems to be working ok with REW. So far, I've been using my older Radioshack SPL meter with Sonny's calibration file. My question is, how much better would using a Behringer ECM8000 mic be?

I'm not against going this route, but it does involve a fair expense, as one needs a phantom power pre-amp, a mike cable. Would I have to get my mic invidually calibrated, or would Sonny's calibration file for it produce respectable results?

Download Makalah Psikologi Pendidikan Pdf To Doc. Basically, what, if any, are the benefits of a mic setup over using the RS SPL meter's mic? Man, I hope my FBD comes soon. My room has a huge peak at 40hz. My search on the internet revealed calibration files from various sources that were extremely close.

Close enough that I simply use Sonnies ecm8000 cal file. The ecm8000 is quite accurate and you won't find the discrepancies that are widely reported with RS meter. I can't back up that discrepancy, but there it is. Brucek, I've looked at this cal file, and one I use for the Ignuz plugin for my Squeezebox, and finally the sample response curve for the ECM8000 on the Behringer website ( ). Sonnie's file is down 3dB at 20Hz and 9dB at 20KHz (if I'm reading it right).

The cal file I have for Ignuz, comparatively, is down only.1dB and 4dB at those frequencies - which is much more in keeping with the spec curve provided by Behringer. I have no doubt that Sonnie's numbers are real, but it makes me wonder about how much variability there really is for this mic. It makes me wonder about how much variability there really is for this mic Yeah, good question. We're just making the assumption that most decent microphone elements are fairly close. We do know that when we did a large group purchase of the Galaxy CM-140 SPL meter, that they were extremely close between each meter (because Sonnie laboriously checked each one). That was encouraging.

We didn't do comparisons with ECM8000's though. The calibration file we supply on the site is there if people want it. If they want an accurate microphone they need to have their own mic done professionally. The graph on the Behringer site only goes down to 60Hz, so it's not much of a template to make any conclusions about. The only thing we really know is that Sonnie's ECM is accurate. Password Please enter a password for your user account.

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