Table of Contents
AC100 sound mixer
These netbooks use ALC5632 audio codec plus mixer IC which has quite some amount of knobs and switches. Most of them are available for direct manipulation with alsamixer
, GNOME Volume Control
and other applications that interact with ALSA mixers.
Analog Audio Mixer Path
Fear not, here's the diagram from the datasheet that allows one to make sense out of all those confusing opportunities:
Understanding it doesn't require any special knowledge, here's a short legend:
DAC
is Digital to Analog Converter,DACs
module gets digital stereo signal viaI2S
bus from the CPU (VoiceDAC
module is left unconnected an ac100)ADC
does the reverse and can be used to convert sound from inputs to digital form which is then sent overI2S
to the CPU- DMIC is a digital microphone, connected to special pins of the integrated webcam
- A triangle on the diagram means a sound amplifier
- A square marked
Vol
is an attenuator that a user can tweak to reduce the volume of the signal - A square with
M
is a mute switch - A circle with sigma is a module that mixes all the inputs together
- A trapezoid is a mux, a module that allows the user to select only one of the inputs to be connected to the output
Common usage scenarious
Here ALSA control names are used, if you're using alsamixer or other similar software you will not see “Playback” or “Mux” in the control names, that is normal.
Stereo playback on integrated speakers
Should be enabled:
DACL2HP Playback Switch
DACR2HP Playback Switch
Int Spk
Speaker Playback Switch
(i.e. unmuteSpeaker
)
Should be set:
SpeakerOut Mux
toHPOut Mix
SpeakerOut N Mux
toRP/+R
Master and speaker playbacks should be unmuted and set to the desired level.
Proper mono sound via MONO mixer or Speaker mixer is impossible to produce on unmodified hardware, see reversed_polarity_of_one_of_the_integrated_speakers for details. Luckily most usage scenarios do not require that anyway. You can swap polarity of connection of one of the speakers but then RN/-R
would need to be used for the stereo output.
Stereo playback on headphones
Same as stereo playback on integrated speakers but with Enabled:
Headphone Playback Switch
(i.e. unmuteHeadphone
)
Set:
Left Headphone Mux
toHP Left Mix
Right Headphone Mux
toHP Right Mix
To mute the internal speakers you can disable Int Spk
or mute Speaker
.
Recording sound from integrated DMIC
This can be used to record sound from the digital microphone integrated in the webcam module, useful for e.g. VoIP Selected for capture:
DMIC En Capture Switch
DMIC PreFilter Capture Switch
DMICL Mix DMICL2ADC Capture Switch
Set:
I2SOut Mux
toADC LR
Tweak DMIC Boost Volume
and Rec Capture Volume
to your needs.
Recording from external microphone
Selected for capture:
Left Capture Mix MIC12REC_L Capture Switch
Tweak Mic 1 Boost Volume
, Mic1 Capture Volume
and Rec Capture Volume
to your needs.
Save and Restore different sound settings
Don't frighten you do not need to memorize all the above settings. If you select the settings in alsamixer according to your needs type on the command line:
# alsactl store -f <name> </code e.g. <code> # alsactl store -f headphones.state
Now, if you want to switch over to your headphone settings next time simply type
alsactl restore -f headphones.state
Hence, you can save settings for internal speakers, headphones, mute all, etc. If you do not want to type all the above to restore just create a little shell script (name it e.g. setsound.sh) to do that for you.
#!/bin/sh # Set alsa sound to a predefined state # save state via # alsactl store -f <name>.state # call this this by # ./setsound headphones alsactl restore -f {$1}.state
make the file executable
# chmod +x ./setsound.sh
now you can set sound settings by simply typing
# ./setsound.sh headphone