DS-2000 Frequently Asked Questions
Question number FAQ-0668
How to check if the microphone is functioning correctly as part of a routine check using the SC-2120 acoustic calibration when measuring the DS-0221 + MI-1233 + MI-3110 combination.
As an example, let's assume the sensitivity of the MI-1233 and 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) (RMS value) |
|---|---|
| MI-3110: Preamplifier Gain | -3 dB |
When the SC-2120 acoustic calibration 's reference sound pressure of "94 dBspl (1000 Hz ± 10 Hz)" is applied to the microphone, the theoretical value of the voltage input to the DS-2000 is as follows:
The MI-1233 microphone outputs a signal of "-29 dB," and the MI-3110 amplifier further reduces this voltage by "-3 dB," which is then input to the DS-0221. Therefore, the input voltage is;
-29 + (-3) = -32 dBV (RMS value)
If you set "Unit calibration OFF" in the DS-0221 FFT analysis software (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 a margin due to environmental conditions, effective value).
It will be.
With the SC-3100 acoustic calibration (reference tone: 124 dBspl 250 Hz ± 1 Hz), the following values are obtained:
The power spectrum value is: -2 dBV ± 0.5 dBV (±0.5 is a margin due to environmental conditions, effective value).
| Reference sound pressure (dBspl) | Spectral values observed by voltage (dBV RMS values) |
|---|---|
| 94 | -32±0.5 |
| 124 | -2±0.5 |
Checking whether the value approximates this value can be used as a routine check.
We can perform a thorough inspection of the MI-1233 microphone in accordance with "JCSS" standards. If you require this service, please contact your nearest sales office.
Last updated: 2006-07-18