What is Mastering?

Audio Mastering by Ian Stephenson @ Simpson Street Studios


Mastering is the final quality-control process before the CD factory.  It’s purpose is to take finished mixes and turn them into a form that is ready for production.  This includes:

  • Checking for overall frequency imbalances, ie too bass-heavy, not bright enough, and subtly compensating for those imbalances using high quality EQ.
  • Check vocal level, check mono compatibility (for radio/tablet/phone speaker listening).  Check stereo width.
  • Dynamic Range Manipulation – Making sure the mixes have maximum impact by increasing or decreasing dynamic range if needed
  • Balancing overall perceived loudness of individual tracks, so they fit together as an album/EP.
  • Putting the tracks into the right order, checking fade-ins/fade-outs, length of gaps between tracks (if any), putting in track markers where one seamless piece of music should have separate track markers within it ie. classical suite or gapless concept album.
  • Creating ‘The Master’ – a DDP file – This is a file which contains all the audio in one long stream and a set of embedded data about track listing, artist, track names, lengths of gaps, track marker positions, barcode number (if using), CD title, ISRC codes (if using – these are unique track identifying codes generated by PPL, to help your tracks get identified correctly for radio etc.).  This is an essential type of file which is better than separate WAV audio files in many ways:  a) the audio is one long stream – so the factory cannot put tracks in the wrong order b) the data is embedded – so the factory cannot track info on the wrong track, or make other CD text errors. c) it includes a data integrity checking system – so the factory can check they’ve received your master file in it’s entirety, without errors when it gets sent via the internet. d) The relative volume of the tracks is left as intended – some inferior CD plants can inadvertently boost the volume of all individual tracks to maximum, ruining the carefully planned volume of tracks so they run into each other in a pleasing way.
  • Adjusting the overall frequency balance and loudness by listening on a range of playback systems:
    • Mastering Quality Speakers in an acoustically designed environment – Dynaudio BM15A speakers @ Simpson Street Studios
    • Kitchen Radio – a mono, poor quality, typical kitchen radio
    • Home full range hifi
    • Car Stereo
    • Stereo Laptop Speakers
      • Balancing frequencies based on these listening tests should result in a ‘perfect average’ tonality, so that any listening system shouldn’t be too far from the ideal sound.  Smaller speakers have less low bass, high-treble frequencies, so checking the sound with these speakers might reveal, for example, that vocals are too loud on smaller speakers – this can be adjusted a small amount, until the perfect average is achieved.
  • All the above decisions are made whilst constantly referencing existing mastered albums, tracks by similar artists or bands which the client has recommended – as a constant reality check, and to make sure the resulting sound stands up to the quality of existing commercial releases as well as possible.

Why Choose Ian Stephenson at Simpson Street Studios?

  • Acoustically Designed Mix-Room, very accurate +/- 4db 20hz-20Khz
  • Mastering grade converters and speakers
  • Specialist in acoustic music, sound quality is highest priority
  • Experienced in dealing directly with CD manufacturers
  • Free advice on copyright, artwork, other production issues
  • Fast, Good Communication, delivers on time
  • Excellent value for money

Audio Examples