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.
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 via I2S bus from the CPU and the VoiceDAC module gets mono signal from a digital microphone (placed somewhere inside near the webcam)ADC does the reverse and can be used to convert sound from inputs to digital form which is then sent over I2S to the CPUVol is an attenuator that a user can tweak to reduce the volume of the signalM is a mute switchHere 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.
Should be enabled:
DACL2HP Playback SwitchDACR2HP Playback SwitchInt SpkShould be set:
SpeakerOut Mux to HPOut MixSpeakerOut N Mux to RP/+RMaster 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.