DS-2000 Frequently Asked Questions
Question number FAQ-0668
A method to check whether the microphone is functioning normally as part of routine inspections using the SC-2120 acoustic calibration device in combination with DS-0221, MI-1233, and MI-3110 measurement.
For example, the sensitivity of MI-1233 and the sensitivity of the MI-3110 preamplifier are as follows.
| MI-1233 microphone sensitivity (as stated in the datasheet) | 35 mV/Pa, -29 dB (0 dB = 1 V/Pa) (effective value) |
|---|---|
| MI-3110: Preamp Gain | -3 dB |
When a reference sound pressure of '94dBspl (1000Hz±10Hz)' is applied to the microphone using the SC-2120 sound calibration device, the theoretical voltage input to the DS-2000 will be as follows.
The microphone outputs a signal of '-29 dB', which is further reduced by '-3 dB' by the MI-3110 amplifier, and is then input to the DS-0221. Therefore, the input voltage is;
-29 + (-3) = -32 dBV (RMS)
In the DS-0221 FFT analysis software, set 'unit calibration to OFF' (if unit calibration is ON, set the calibration value to 1.000 V/EU);
The power spectrum value is: -32 dBV ± 0.5 dBV (±0.5 is the margin due to environmental conditions, effective value)
will become.
The SC-3100 audio calibration device (reference sound: 124dBspl 250Hz±1Hz) will have the following values.
The value of the power spectrum is: -2 dBV ± 0.5 dBV (±0.5 is the margin due to environmental conditions, effective value)
| Reference Sound Pressure (dBspl) | Values of the spectrum viewed in voltage (dBV effective value) |
|---|---|
| 94 | -32±0.5 |
| 124 | -2±0.5 |
By checking whether it is close to this value, it can be considered a routine inspection.
The precision inspection of the MI-1233 microphone can be conducted based on 'JCSS' standards at our company. If you are interested, please contact your nearest sales office.
Last updated: July 18, 2006