Internal microphone not working

[Nat]

On build 193 I can't seem to make the built-in microphone work. In alsamixer, I can choose between mic1 and mic2. mic1 works fine when I plug an external microphone, but the internal microphone doesn't seem to work wether I'm set on mic1 or mic2.

[Nat]

It appears that both the internal and external microphone are linked to the mic1 entry in alsamixer, however, there is a huge hum (ground loop ?) when using the internal microphone. If I tap on the microphone with a finger I can hear it using headphones, but it doesn't work at all in TamTam when I try to record.

[mfoster]

This is a fundamental I.D. problem, which places the mic too close to the right speaker, and causes feedback. If you disable the right speaker, the microphone works well. We will attempt to relocate the mic either for the B2 or B3 builds.

[Jason Liu]

Replying to Nat:

Regarding the internal microphone can't work well issue ,We find the internal microphone cable was reversed ,

so we need swap the two wire cable . The AC'97Codec mic1 for internal and external microphone input .

BR, Jason

[jg]

Need to get in the release notes.

Need to verify the cabling is fixed in B3.

Also, IIRC, the default ALSA settings are wrong, causing feedback.

[jg]

Investigated carefully. One vendor's mike is bad, and there are bias problem.

[wad]

Significant changes have been made between the filing of this bug and the B3 build, including moving the microphone and providing it with a nice short, shielded cable.

This bug is closed, to allow newer, more relevant microphone bugs to be logged separately.