Mastering the mix tutorial

So you've got your phat tune down and you've got your audio mix to perfection, but it still doesn't quite have the same sparkle and life as the commercial songs in your CD collection... it's time to master your song.

What is Mastering?

Mastering your song is the difference my friend, it's simply the difference! You might think your mix sounds hot now, but next to your mastered version, it'll sound knackered.


  • What is Mastering?
  • Mastering Tools
  • Hardware Mastering Devices
  • Mastering Basics
  • Noise Reduction Techniques
  • Clicks, pops, crackles
  • Audio Editing - Getting up close.
  • Audio Noise Reduction Software
  • Hum and Hiss Removal
  • AC Hum removal
  • FFT Filtering - Profile to Kill

To explain it simply is to under-play its importance... but anyway, a pro mastering engineer will usually mess with the equalisation to bring out the best colours in the mix, they'll apply compression to give it some punch and presence and they will also maximise loudness!

But don't let the simplicity fool ya - It's very easy to mess up and that's why it's always advised to use a professional mastering engineer trained to understand and work within a ridiculously accurate monitoring environment.

So that explains what mastering is, before the theory of how to do it, let's introduce some of the acclaimed mastering tools to become familiar with...

Mastering Tools

Hardware Mastering Devices

TC Finalizer - Has all the mastering tools you need in one rack unit TC Electronic Finalizer Express

Software Mastering Tools

Any good audio editor such as:

Those same wave editors are capable of using individual mastering plug-ins such as:

Mastering Basics

First, the order in which your mastering effects kick-in greatly affects the overall sound. Although various mastering engineers will differ in practice (and oppinion), the general consensus will be to process the mix in the following order:

  1. Noise reduction
  2. Equalisation
  3. Dynamics
  4. Harmonic exciters
  5. Stereo widening
  6. Loudness maximisers

Noise Reduction

OK, if your mix has any unwanted transient sounds such as, clicks, rumbles and pops etc... (which could be caused by the singers mic or even poor quality plug-in effects for example), it will mean that when we try to increase the gain, we also increase the volume of the transients too... they can be easily missed and so now they must die!

Hopefully, they will have been removed during the mixing process but some transients do slip through so a mastering engineer will just make sure. Note: Mastering engineers have one-up on your usual bedroom-artist in that they use special loudspeakers and subwoofers which have an infrasonic response (below audible levels).

If we can get rid of these transients, we gain more room to increase overall volume, so let's look at how you might do this next.

Noise Reduction Techniques

Well, if it's not too late, the best way to reduce unwanted noise in your recording is to... record it again! - I know, it's typical of the kind of answer that accounts for so many hospital injuries (to the engineer) and court appearances (for you) but, it could be quicker (and cheaper) in the long run.

Clicks, pops, crackles

If you decide to forego the benefits of accelerated fame via (media-covered) court appearances, and you can't be bothered to re-record, what can you do, where can you go?

You've two choices: close-up wave editing in your audio editor, or, use quality audio processing software tailored specifically to do the job - I emphasise quality because it's all about advanced algorithms that're dreamt up and programmed by advanced geeks. THIS, is often the defining difference when it comes to amateur freeware written by enthusiastic hobbyists and the results of a professional mastering engineer (Normal conditions and caveats apply to that last statement - no emails please!). So let's learn more about close-up wave editing...

Audio Editing - Getting up close

It's easy to explain this (for once!), but time-consuming to do. If the offending noise is only a few samples (typical of clicks, pops and (short) crackles) then locate, zoom-in very close and, using the pencil tool, cut-down the amplitude.

Some audio editors (like Soundforge) have menu functions to pick-out and move the cursor to certain unwanted "glitches" quickly.

Audio Noise Reduction Software

For anything longer than just a few short samples, you'll really need to use special noise reduction software. The dedicated algorithms used are specifically programmed to target short transients typical of clicks and pops etc... Two notable plug-ins that are good for the job are:

Hum and Hiss Removal

Removing hum and hiss from the mix is much more difficult. First of all try to fix the source of these sounds before recording, 'cos getting rid of them from within the mix later can have unwanted effects on the overall sound (it might sound "flatter" for example)... in other words, fix and re-record for best results (don't hit me), otherwise, read on.

Typical culprits to tame might be a dodgy sample source (if using them), poor soundcard or low recording levels, to name just a few.

Hiss-noise is typically found holidaying in the 8-14Khz frequency area - Now, you could go in with a parametric equaliser and deploy shock and awe tactics to overthrow the delinquent hissy but you'll probably end up ruining the total higher frequency soundscape...

... hence why it's imperative (for ultimate results) to use purpose-built software like:

AC Hum removal

AC hum, depending on your luck, may be easier to deal with. I mention luck because if you're blessed with it then you might find that simply targetting the frequency-range of 60-80Hz in a parametric equaliser - set to a narrow bandwidth - and applying maximum cut can get rid of it... easy!

But if that doesn't work though your luck is out. That hum-bugger will have fellow hum-buddies in the form of harmonics which can reside in the following freq areas: 120, 180, 200, 350 and 420 Hz bands... it's not your day face it. You'll need to consult the professional services of another dedicated plug-in lest you ruin the mix by "muddying" the low and mid-range freq bands due to control-thuggery-syndrome. A good plug-in for hum-removal is:

  • Waves X-Hum (see below)

FFT Filtering - Profile to Kill

FFT filtering, as it's sometimes known, may be a more reliable method of removing all these noise artifacts in one go... if, you have a section of track that contains just the offending sounds alone.

FFT filtering basically samples the chosen track section and creates a noise profile which it can then use as a template from which to detect and slaughter all noise shrapnel from the entire mix.

Some wave editors have this function so go look! Otherwise, notable plug-ins are:

  • Waves X-Noise (see below)
  • Sonic Foundry's Noise Reduction plug-ins

Caution Needed!

With all this noise reduction, caution is needed... even when using quality software. You are altering the sound at the end of the day and sometimes this may affect frequencies you want to preserve. So make sure you perform any of these techniques first on a copy of your song.

Finally, do consider re-recording where these techniques don't produce the best results - second-best is NOT good enough - and where mics are involved... don't wear those shiny plastic pants... OK, put your fist down, I'm off to write the next part of this mastering tutorial now.

Waves Native Restoration Bundle (Macintosh and Windows)

Intelligently learns from a section of noise, and then applies a broadband noise reduction to eliminate background noise from any source. Primary controls are similar to classic dynamic processors. Eliminates learning curve.

Effectively removes clicks from 78's or vinyl records, as well as spikes arising from digital switching or crosstalk. Operates Fully Automated or Manual Click Removal.

The second stage in record restoration eliminating crackles and surface noise.

Eight harmonically linked notch filters attenuate ground loop hum by up to -60dB. High pass filter options remove rumble, microphone pop and DC-offset.

Mastering Tutorial - Part 2

Comin up! We look at equalisation (EQ) when mastering - No, it's not quite the same as when mixing.