Welcome to the dark voodoo of audio mastering, Rune. There is no quick rundown on this very topic, nor would I imagine a space for it here, at least not in all its necessary depth. As for information sources, there are a few knowledgeable people on recording.org. For instant gratification, I'd recommend getting a TC Electronics Finalizer. As for the process: Mastering (or pre-mastering as it's precisely called) is the step in working on your audio right before it goes to your destination medium. Its goal is to make the audio experience enjoyable for the listeners. Usually, you won't do anything related to mastering within Ableton - and if you still do, a mastering engineer to whom you give your material for production will slap you silly. A proper way of doing things would be to record a clean mix in you DAW application in a "deep" format (meaning 32 bit) and then doing the mastering in a completely separate step - in an audio editor as WaveLab or Sequoia using dedicated plugins, or even using outboard - mostly analogue - hardware altogether. A primer recommended by a cat on recording.org is http://www.diplo.co.uk/music/mastering.php, but as always, take the gospel with a grain of salt. And make sure to master in your bedroom after a restless night of sleep - an unmade bed is by far the cheapest efficient bass trap for tuning your room acoustics! > Does anyone have tip on mastering - and > masteringeffects that works with mac and ableton ?