What is Mastering?

Mastering is the process of preparing and transferring recorded audio to a medium that will be used in the production of copies. In my case as well as many others probably reading this is CD’s. Some may need the audio to go to television, and the process is similar, but some high-pass and low-pass filters would need to be applied.

Generally there are around 4 steps to Mastering a track for it’s destination.
1. Load the recorded audio tracks into the DAW*. (explained next)
2. Correct any problems with the audio, such as volume level, tonal balance, or undesirable artifacts.
3. Sequence the separate songs or tracks as it will appear on the final product (for example, a CD).
4. Transfer the audio to the final master format (i.e., Redbook, CD-R, etc.).

What’s a DAW? A DAW is a Digital Audio Workstation. While almost any home computer with multitrack and editing software can function somewhat as a DAW, the term generally refers to more powerful systems which at minimum have high-quality external ADC-DAC hardware, and some usable audio software, some of which is commercial such as Logic Pro, Pro Tools, Cubase, SONAR, and Digital Performer, some of which is free software such as Audacity or Ardour. Most likely you have Logic, Pro Tools or Cubase. If you have none of these – you can get Audacity (while seemingly weak and underfeatured, is actually a very good program) for free here.

Ok, now we have our DAW, we have our blank CD and CD burner…what do we do in step 2? Here are some examples of what can be done to “master” your track.
1. Apply noise reduction to eliminate hum and hiss.
2. Limit the tracks to set the highest peaks in audio volume to a preset level; the overall audio should never exceed 0 dBFS.
3. Equalize audio between tracks to ensure there are no jumps in bass, treble, midrange, volume or pan.
4. Apply a compressor (for example, 1.5:1 starting at -10 dB) to compress the peaks but to expand the softer parts.

While these are simply guidelines, you’ll find that they’re a nice little base to start with. Make sure your songs go together. This is my biggest error. I will think I have a CD complete and ready to burn mass copies of to give to my friends and when I stick it in my car, track 3 will be much softer than track 2 or track 5 will be much louder overall than the rest of the tracks. Make sure they’re comparable, and listen to them on different systems because your computer speakers/headphones may be disguising some sounds and leaving some bass and high trebles out completely. This brings me to RMS

The Root Mean Square (RMS) in audio production terminology is a measure of average level and is found widely in software tools. In practice, a smaller RMS number means higher average level; i.e. -9 dBFSD RMS is 2 dB louder than -11 dBFSD RMS. The maximum value for the RMS number is therefore zero. The loudest records of modern music are -7 to -9 dBFSD RMS, the softest -12 to -16 dBFSD RMS. The RMS level is no absolute guarantee of loudness, however; perceived loudness of signals of similar RMS level can vary widely since perception of loudness is dependent on several factors.

For more reading on track/album mastering check out http://www.musicbizacademy.com/articles/gman_mastering.htm

Coming soon – tips on recording with your Microphone.