USB Measurement Microphones level calibration

At this point we would like to summarize some general information on the subject at level calibration of measurement microphones.

The classic setup for PC measurement system consists of

Measurement Software

USB sound card with phantom power P48

Measurement microphone (electret with phantom power)

Sound level calibrator

If you
connect and configured everything properly and starts to measure the sound level, the software will usually display something negative, such as -33.5dB (A).
Typically, this is the level with respect to the full-range of the AD converter and has nothing to do with the absolute sound level

First, we need to calibrate the entire measurement chain : This can be done with a handheld sound level meter, place it close to the microphone (not very precise), or with a sound level calibrator (expensive).
Unfortunately, you have to this this again once you  touched the gain on the sound card or mixer for Windows. The setup is no longer calibrated.

In addition, overload conditions are difficult to detect since all the signal stages are unknown. Actually, a full measurement would be required to document the maximum and minimum level ranges. 

It is already evident from this brief description that you have to be very careful when you measure the sound level. Beginners fall regularly in several major pitfalls and even professionals have quickly forgotten a little thing, and this causes a measurement with significant errors.

We believe
, that our new USB measurement  microphones solves all these problems. Finally, we are at the point:  Install the software, connect the microphone, launch the software and measure immediately calibrated absolute sound levels.

This is possible, because software, microphones, preamps, and soundcard are one
unit. Everything is calibrated by the manufacturer.
The software also controls the gain
of the windows mixer. Furthermore, the measurement ranges are displayed correctly, so you know which level ranges can be measured correctly. The measuring ranges can be selected simply by a mouse click. Over- and underload conditions are displayed correctly

Ultimately, these are all things that you
expect from hand sound level meter since many years, no matter what price range. And consequently you can expect this from high quality PC-measuring systems as well.

For reliable measurements of course, you can will need a calibrator. But it serves only (as with any hand sound level meter) for the periodic review and not to  get rough values.

The USB measurement microphones
, that are currently on the market, are all USB audio class compliant. Therefore work with any software, but the above-described automatic level calibration, work only on systems where software and microphone are perfectly matched and the software controls also the Windows mixer. This is obviously the case with our complete solutions.



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Last modified: Februar 05, 2013