Accuracy for home night noise measurement

edited December 1969 in SoundMeter

I would like to measure noise level in some apartments at night. I estimate that noise level is somewhere between 25 - 35 dB.

I can calibrate my iPhone with a calibrator. I.e. play 94dB sound at 1 kHz to iPhone and adjust it to show correct reading. How accurate reading can I get with SoundMeter after calibration?

According to IEC 651 Class 2 sound meters should have accuracy of +-1.0 dB and class 3 devices +-1.5 dB.

Class 2 sound meters cost close to 100$ and I found no class 3 devices for sale.

Would a calibrated SoundMeter get close to class 3 device accuracy?



  • Zimbo,
    How accurate reading can I get with SoundMeter after calibration?
    If you calibrate at 1 kHz, then you should easily be able to achieve accuracy within 0.1 dB at 1 kHz. You should be aware of the current high-pass filtering applied the iPhone's built-in microphone. This issue is discussed on our blog.

    If you need true class compliance, then you'll need a dedicated sound level meter build for that purpose. MicW makes a microphone that plugs into the headset jack that they claim conforms to standards for Type 2 sound level meters. However, the iPhone's headset input also passes through the high-pass filter.

    We're hopeful that Apple will provide developers with a means to bypass the mic input filter, but we won't know for sure unless/until it happens.

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