Dayton Audio iMM-6 External Mic

Bruce

Hi, is it possible to calibrate a Dayton iMM-6 to an iPhone 4 running SoundMeter 7.0.1.  Any assistance would be very much appreciated.

Cheers...Bruce

benfaber

Bruce,

Here's an excerpt from a recent blog post regarding SoundMeter's hardware support:

The new SoundMeter apps also support the Dayton UMM-6 USB measurement microphone. When the UMM-6 is detected, the user will be prompted to enter its serial number, which is typically printed on a label on the UMM-6. If a valid serial number is entered, SoundMeter will automatically download a calibration file from Dayton's website and set the microphone sensitivity based on the information in the file.

Note: The Dayton UMM-6 must be connected to your iOS device via Apple's USB camera adapter (either for Lightning or 30-pin dock connector, depending on your device). Sometimes the UMM-6 shows up in iOS as USB PnP Sound Device. If that happens, unplugging the UMM-6 and plugging it back in will generally solve the problem (it may take 2 or 3 tries). When properly connected, "UMM-6″ will appear as the input device name in SoundMeter's toolbar (at the top of the screen).

This should work the same on any iOS device that runs the current version of SoundMeter.

Please let us know if you have other questions.

Bruce

Hi, the Dayton UMM-6 is a USB device.  I've purchased the Dayton Audio iMM-6, this microphone connects via the TRRS headphone jack.  Some apps such as Studio Six Digital import the calibration file provided by Dayton Audio.  I though the Faber app may have provided similar functionality.

The following link from Dayton shows the procedure for the Studio Six app.
http://www.daytonaudio.com/index.php/imm-6-idevice-calibrated-measurement-microphone.html

Cheers...Bruce

benfaber

Bruce,

I'm sorry, I obviously misread your post.

Are you looking for frequency response compensation (FRC) or sensitivity calibration? If you are looking for FRC, it is not supported in SoundMeter. FRC only works with FFT-based spectrum analysis.

If you are looking for sensitivity calibration, then you would need to enter the iMM-6's acoustic pressure sensitivity in the Input Channels calibration screen (there is calibration tutorial information in SoundMeter's built-in documentation).

The iMM-6's calibration file includes the mic's overall sensitivity on the first line. (You can download the file directly at http://www.daytonaudio.com/iMM6_Lookup_Tool/iMM_Text/99-00192.txt, where you replace "00-00192" with your own mic's serial number.)

The nominal sensitivity for the iMM-6, given by Dayton, is -40 dB, where 0 dB = 1V/Pa. To convert that to V/Pa (to enter into SoundMeter), you need to raise 10 to the power of the sensitivity divided by 20. That is, 10^(-40/20) = 0.01 or 10 mV/Pa (which Dayton also gives as a nominal sensitivity). The sample file they provide has a sensitivity of -37.4 dB, which equates to a sensitivity of 10^(-37.4/20) = 13.49 mV/Pa, which you could enter into SoundMeter either as "13.49m" or "0.01349" (SoundMeter can recognize the "m" and format the number appropriately).

Keep in mind that you need to have the headset input device units set to "V" and the headset input channel units set to "Pa" in order for this to work. Also, you'll still have a nominal calibration. If you need a more accurate calibration, I would recommend performing a relative calibration against another sound level meter that you know has been accurately and properly calibrated. (I recommend this, regardless of which or whose iOS sound level meter app you are working with.)

Please let me know if you have questions about any of this.

Ben

Bruce

Hi Ben, appreciate the help...I'll do what you have recommended.

Cheers...Bruce