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CWizard 10-16-2005 10:53 AM

Microphone issues on Intel integrated audio
Problem: I have two microphone inputs, one (front) works while the other (rear, prefered) doesn't, and I can't get either to playback directly. I really need this, because my TV card uses the audio card's mic for sound.

The computer is a Dell Dimension 5100 (pretty new) with integrated sound card:
* Chipset: Intel 945G Express
* Audio: Inte High Definition Audio
*** lspci: 00:1b.0 Class 0403: Intel Corporation 82801G (ICH7 Family) High Definition Audio Controller (rev 01)
*** alsamixer: Card: HDA Intel, Chip: SigmaTel STAC9221 A1
* Slackware 10.2 / Kernel (compiled with ALSA, no OSS)
* It has a "rear mic" on the back together with the other connectors, and also front mic and headphone connectors.

AlsaMixer has the following controls:
* Playback:
*** PCM
*** Front
*** Surround
*** Center
*** LFE (can unmute and change it, but it always resets. What is "LFE"?)
*** Channel: 2ch or 6ch (I have it on 2ch)
*** Input Source: "Mic", "Front Mic" or "Line"
* Capture
*** Capture (set on 100%)
*** Mux (set on 100%)

I can record and replay (eg using Krec) with the front mic if I set the Input Source to that, but not with the rear mic.

Thus I have two problems:
* Get the "rear mic" to work at all
* Get either mic to play directly to the speakers. I've never had any trouble before doing this before.

One observation that might relate to the rear mic. I booted up Windows, and noticed that when I poped in a mic in the rear, Windows poped up a window asking me if I had inserted a microphone, and only when confirming that, was it enabled. So there may be some subtle switch that must be enabled for it to work. Nothing similar with the front mic, though.

All ALSA modules seems loaded ok, and sound works good otherwise.

Excerpt from amixer:

Simple mixer control 'LFE',0
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined
  Playback channels: Mono
  Limits: Playback 0 - 127
  Mono: Playback 0 [0%] [off]
Simple mixer control 'Capture',0
  Capabilities: cvolume cswitch
  Capture channels: Front Left - Front Right
  Limits: Capture 0 - 14
  Front Left: Capture 14 [100%] [on]
  Front Right: Capture 14 [100%] [on]
Simple mixer control 'Channel Mode',0
Simple mixer control 'Input Source',0
Simple mixer control 'Mux',0
  Capabilities: cvolume
  Capture channels: Front Left - Front Right
  Limits: Capture 0 - 4
  Front Left: Capture 4 [100%]
  Front Right: Capture 4 [100%]

Again, I do not know what LFE stands for. And, those "Channel Mode" and "Input Source" looks weird, but there seems to be no way of changing that.

Any help with these problems are greatly appriciated!

CWizard 10-18-2005 03:27 PM

*** bump ***

Any ideas at all?

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