Microphone bias

Microphone bias

[Daniel Drake]

Hi,

I'm working on CX20582 HDA support for OLPC.

We have a choice of 50% or 80% microphone bias on the 2 microphone ports
(one inbuilt, one socket for external devices). Any suggestions on which
one we should pick or how to decide?

We can't hear any difference between the 2 settings..should we choose
50% for potential power savings?

Daniel

Re: Microphone bias

[Tony Vroon]

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On Mon, 2009-07-13 at 09:50 +0100, Daniel Drake wrote:
> We have a choice of 50% or 80% microphone bias on the 2 microphone ports
> (one inbuilt, one socket for external devices). Any suggestions on which
> one we should pick or how to decide?

For the external devices, it tends to depend on the headset. I would
suggest going to eBay or a random computer shop and getting a few
different ones. Some may require 80% to produce a usable signal,
particularly the cheaper ones.

> We can't hear any difference between the 2 settings..should we choose
> 50% for potential power savings?

If your internal mic works fine on 50% bias I would keep it there, yes.

> Daniel

Regards,
Tony V.

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