Silence measured with REW RTA and suspicious calibration files

[serial]

Hi,

I'm concerned about the correctness of my UMIK-1 calibration files after I've measured silence with REW RTA. I bought the mic not from Cross-Spectrub Labs, so the files are downloaded from the minidsp website.

On the graph, you can see 4 measurements - spectrum mode vs RTA 1/48 octave mode, and 90 degreee calibration file vs no calibration file. The horizonal lines are recorded with RTA 1/48 octave mode, the downward sloping lines are with the spectrum mode. The lines which look smooth between 3 kHz and 20 kHz are recorded without a calibration file, and the lines which go up from 7kHz are with the 90 degree calibration file.

The line around 0 dB is the calibration file itself.

The measurements with the calibration file look pretty weird and not natural. Can someone confirms that they do not look correct? If yes, what can I do? Can I assume that silence is supposed to produce a horizontal line in the RTA mode and create my own calibration file from the measurement I get?

 

[serial]

Well, maybe the 90 degree calibration file is not supposed to be used in this case because we don't have a sound source, so here is the same with the 0 degree calibration file:

 

[MaxwellsEq]

I don't think anyone will know what silence should look like at your location. Even so, I think it's unlikely that it will be a horizontal line or even a slope of some type.

 

[JohnPM]

The calibration file compensates for the response of the mic in the presence of a signal. At very low signal levels the mic's self-noise will become the dominant component and the calibration file would no longer be appropriate.

 

[davidki]

Has anyone found a specific calibration file for the Behringer ECM8000? I have spent hours between rereading different posts on various forums and searching the non existant information on the Behringer website (Ill never buy another Behringer product ever) I can not see anyone post a link to a place to get the specific file from Berhinger. Like others I'd like to use REW with a cal file. I see posts about a generic cal file on the Berhinger website but like others mention the files for mics like the UMK1 are specific per mic!

On another Topic... has anyone ever found information on the Phantom Power on the Behringer Ultra-Curve Pro DSP 8024 I have researched this thing to no end ... In the manual is show Phantom Power 15v and in the instructions it says to turn on Phantom Power but looking through every option on the unit there is nowhere they show to turn phantom power on or off.... I even went back to several versions of the manual and there is not one that shows the location either manually or in software menu to turn on Phantom power... .Again another issue with Behringer products! Anyone have one of these and been able to find a Phantom Power Switch to turn it on and off?