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Discussion Starter #1
I came across lot of discussion about measurement mic and their calibration. Dayton EMM-6 provides calibration file if you enter the serial at their website.
Cross-spectrum charges the 30$ extra for mic to get it calibrated.
There is also a calibration value file at download area of this forum.
I am planning to use my mic for room modes measurement and frequency response of my speaker systems.
Can someone clearly define the advantage of getting calibrated from cross-spectrum vs using values from Dayton?
Parts express assures it is calibrated for each individual unit and not even for the same batch. There are some trust issues here.:gulp:
 

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Cross - Spectrum also sells them, calibrated and all.

Depends if you intend in using a EQ also for accuracy.

What i have seen Dayton do a reasonable job.

The advantage is accuracy and for the small price i think it is worth it.
 

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Discussion Starter #3
Thanks Phillips.I am wondering if you can explain more. What would be considered a resonable vs more accurate?
What all improvements can I expect from using a calibrated mic over the one using Dayton calibration data?
 

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My file attached

The scale is different but shows clearly the difference.

The Red is Dayton calibration (20- 20,000hz) the other Cross - Spectrum (5 - 25,000hz).

Hope this helps.

comparison calibration.jpg
 

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Discussion Starter #7
Do you think behringer MC8000 will have a better frequency response? I mean with the peakiness at 10KHZ
 

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No, all the low cost mics have significant SPL deviation in the low and high ranges and there is significant variability between individual mic.

When an accurate individual calibration file is loaded into REW the mic response is corrected and the room response measurements become accurate.
 

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Discussion Starter #10
John,which calibration files you are referring to,one on download area or one Dayton audio provides?
 

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John,which calibration files you are referring to,one on download area or one Dayton audio provides?
I was commenting on your post 7 regarding whether the Behringer mic would be inherently better. It would not be inherently better. It would be similar for SPL uniformity.

I mentioned that an "accurate" cal file is needed to accurately correct the SPL response of any low cost mic. If your going to EQ the HF then an accurate cal file is needed. I didn't initially comment on the source of an accurate file as I thought the charts posted made it clear which ones were not accurate.

I have seen several of mic cal files from top line manufacturers. A consistent characteristic is that the cal curve is relatively smoothly changing. It does not seem feasible that one could rapidly change up and down 1-3 dB with a small change in frequency. My overall conclusion regarding the Dayton cal files posted above is similar to JohnM's. I would recommend that they are not used. They just bounce up and down much more than any real mic response would.

For LF measurements only, the generic calibration file in the download area, or even using no cal file, is probably acceptable. Many people here that are EQ'ing the SW are not targeting a flat house curve anyway. I don't think that even a 2-3 dB error at 30 Hz is a practical issue, but others may disagree. The error is not likely to be greater than that for most mics. There may be a few however! Going lower than 30 Hz increases the possible error significantly so a good calibration curve is then a good idea.

I am using the CSL cal files for the Dayton mic I purchased. I have not seen any evidence to suggest that they are not accurate. I have confidence that this is a well controlled lab that offers a very affordable calibration services. I got this impression by reading all Herb's (Anechoic) comments in the various threads. He seems very knowledgeable and committed to providing a quality service.
 

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John,which calibration files you are referring to,one on download area or one Dayton audio provides?
Too many Johns in this thread :) I am referring to the Dayton files as shown in the plots by JohnR in post 4 and JohnT in post 6. Whatever process Dayton used to produce those is fatally flawed.
 
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