IOS obtains microphone audio input data (PCM) and calculates DBSPL, resulting in a significant difference from the actual value

Media Technologies Audio
jumpx OP
Created Jul ’23
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Using the OC framework AVFAudio, obtain PCM data for the 32-bit microphone of the device, and the results obtained are all between -1 and 1 (the actual value of the fixed noise source has exceeded 100 decibels). According to the conversion results, it cannot exceed 100 decibels (20 * log10 (PCM/0.00002)). Do you know what the reason or problem is?

Output： -0.82569194 -0.82774025 -0.83398014 -0.87197787 -0.90468484 -0.9037836 0.9085202

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IOS obtains microphone audio input data (PCM) and calculates DBSPL, resulting in a significant difference from the actual value
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