Notice of Error in Test Report for MI-3111 Microphone Preamplifier

Thank you for your continued patronage of our products.
We have recently discovered that there are errors in the measurement values listed in the test report for the MI-3111 microphone preamplifier.
We sincerely apologize for any inconvenience caused to our customers. We would like to inform you of the details of the error and the measures we are taking to address it as follows. We kindly ask for your review.

1. Target Products

2. Details of the problem

In the insertion loss test, the measured value was 0.60 dB lower than the actual value, and this was recorded in the test report.

In the example above, 1.21 dB is the correct insertion loss value.

3. Influence on measurement

When performing unit calibration using an acoustic calibrator

Since we will not be using that insertion loss value, it will not be affected.

If unit calibration is performed using the insertion loss value in question.

If you are calculating the calibration value using the sensitivity value of your microphone and the insertion loss value of the microphone preamplifier, the calculated calibration value will be 0.60 dB higher than the correct calibration value, and as a result, the measured sound pressure level will be 0.60 dB lower than the correct value.

Therefore, to obtain the correct sound pressure level, please add 0.60 dB to the measured value.

example:

If the measured sound pressure level is 94.00 dB
94.00 dB (measured value) + 0.60 dB = 94.60 dB (correct sound pressure level)

4. Cause

There was a bug in the processing within the test program used in the examination.
When we updated the inspection equipment we were using, we did not change the correction values in the inspection program, resulting in incorrect insertion loss values.

5. Response

Customers who wish to have their test results reissued should contact our Customer Service Center or their nearest sales office.

Regarding inquiries

If you have any questions, please contact our customer service department or your nearest sales office.