Mastering is the process of preparing one or multiple tracks for being transfered to a certain kind of media such as CD, LP or tape. Typical steps in mastering an album typically involves the following steps:
- Editing out little mistakes
- Removing noise and clicks if any, using gates, denoisers, FFT denoisers or whatever needed
- Checking for and removing unwanted subsonics
- Checking the stereo width according to the destination media
- Equalizing the tracks so that they match each other
- Optionally adding exciters, vitalizers, reverb
- Arranging the tracks in their proper order
- Cross-fading between tracks or making the proper pauses between them
- Making the tracks appear to be the same volume
- Limiting or saturating to bring up the global volume
Proper mastering usually also involves in listening to various types of speakers. For certain kinds of music, you even have to consider the target audience and listen to the music in car stereos while driving, mobile phones or similar, depending on the music genre and the behavior of a typical consumer.
Media dependent rules
Various output media has various rules. Generally dealing with analog audio takes both more skill and more expensive equipment, as every single transfer in the analog domain imposes some kind of degradation.
- LPs require subsonics to be removed and the lower frequencies must be mono. How deep you can allow stereo depends widely on the pressing facility and the cutting lathe used. The cheap Panasonic vinyl cutter must have mono below 700 Hz. The Czech based company CZ Media require mono below 300 Hz, and the old Neumann cutting lathe supposedly allows stereo all the way down to 35 Hz, according to an english mastering technician.
- Analog tape typically adds white noise, and adding a bit of extra treble to a dark mix often helps fighting it. Also the over-all volume should be rather loud so that the noise becomes less noticeable. The choice between non-compressed, Dolby A, B, C or DBX must be made.
- CD and mp3 are somewhat easier to deal with as they are digital and far less rules apply. Also, typically the source is digital, making the transfer easier than dealing with analog audio.
- Audio that is to be broadcast over radio or TV should be mono compatible.
- Ring tones can be made louder by high-pass filtering 6dB/oct at 1000 Hz or 12 dB/oct at 500 Hz and then limiting it wildly to bring up the volume. Also, the choice of compression format and settings becomes vital when trying to reduce filesize significantly and still maintain the high frequency end, which these devices play better.
- Studio grade hardware EQs, compressors and preamps