Onboard Mic volume is low and distorted

Peng Shao9

I maxed out the volume for the onboard mic for the Audio Boost demo app, and I can barely hear it in Audacity and the waveform is really distorted. Please help! Am I getting some settings wrong?

AudioCodecMicVolCtrl(AUDIO_CODEC_TI_3254, AUDIO_CODEC_MIC_ONBOARD, 100);

Audio file attached below (16-bit, 16Khz, Stereo). I converted it to WAV so you can play it.

over 9 years ago

0 Aashish Bhanawat over 9 years ago

TI__Genius 16085 points

Hi Peng,

Set Mic volume to 50 rather than 100 as it will amplify the noise will get more distorted audio. To capture audio on higher you need to increase volume level at speaker side.

Regards,

Aashish

0 Peng Shao9 over 9 years ago in reply to Aashish Bhanawat

Prodigy 250 points

I was able to figure out both problems.

Regarding noise:
Ensure that the microphone buffer (readBuffer in the WiFi audio example) always has at least 2xSIZE_OF_READ bytes available to read before attempting to read it - kind of like a watermark.

Regarding volume:
Instead of setting mic volume via TI3254_RIGHT_ADC_VOL_CTRL_REG (page 0/0x54) registers, use the programmable analog gain registers (page 1/0x3C) which will reduce the effect of noise at amplified signal levels.

0 Aashish Bhanawat over 9 years ago in reply to Peng Shao9

TI__Genius 16085 points

Hi Peng,

Please close the thread if issue is resolved.

Regards,
Aashish

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Onboard Mic volume is low and distorted