The software mixer is your "volume commando central" for the final audio output, just before the audio signal gets encoded and sent, as data, to the streaming server. There are different types of mixers for each Operating System, some are very basic and some very complete, but they accomplish the same functions: toggle input/output channels on/off, and regulate the volume of each single channel.

Streaming, we will need the software audio mixer mainly to control inputs: the line/microphone input, and the IGain (also called Capture) input. Once we have configured the desired settings, and, thanks to some listener feedback, the volume quality is at a good level, we will hardly need to change them!

• Mic or Line input is the audio signal comeing from the soundcard
• IGain or Capture is the audio input comeing from any computer software

Every mixer has two functions for each channel:

• an input channel will be active when we turn it on, confirming its activity through a red colored spy!
• the volume level should be maximal at 85%, higher settings could lead to distorsion!

Of course the volume level depends on the volume of the audio signal input. The most inportant remark is, none of the levels should have a too high setting: the more the volume nears it's peak, the higher is the possible distorsion resulting! A good volume setting is a result of an equilibrate combination of all the volume settings in a chain. If you have a dB (decibel) detector near the volume control, the optimate volume setting 0 dB!

• listen to the final volume level trough the headphone output of your soundcard, noticing the audio gets distorted at some point
• relay on feedback from a listener of your stream
• keep all the volume levels to 0 dB

Of course, there are a lot of different software mixers for GNU/Linux systems, and each of them can have different grafical interfaces. However, the most appreciated are: aumix, in terminal and grafical frontend flavour; alsamixer (terminal) and it's grafical frontend alsamixergui; KMix (only grafical frontend) for the KDE environement.

For Microsoft Windows there are also a lot of different mixers, but they are copyright protected. The default mixer acomplishes anyway all the needed functions.

For Macintosh there are also different mixers copyright protected mixer. The default sound control has an hazarduos design, but anyway acomplishes our needs.