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 CPU
• 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

Should be enabled:

• DACL2HP Playback Switch
• DACR2HP Playback Switch
• Int Spk

Should be set:

• SpeakerOut Mux to HPOut Mix
• SpeakerOut N Mux to RP/+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.