Mastered music - the shocking truth about what you really hear (with audio)

The mastering loudness war is not yet over, yet the casualties are piling up. Yet here is convincing proof that it is all so wrong...

By David Mellor, Course Director of Audio Masterclass

Of all the techniques in the armory of the loudness warrior, the nuclear option is clipping.

Yes you can compress and make a track louder, you can limit it too and make it louder still. You can use a multi-band compressor and squeeze as much energy as possible into every frequency band.

But if you want ultimate loudness, then all you have to do is turn the gain up until the signal clips. All those pesky 'peaks' are simply sliced off, allowing the bulk of the signal to be much higher in level.

In the 'olden days' of audio, clipping was absolutely forbidden. One clip would get you fired. Well, maybe the second one.

But now clipping is a standard part of the mastering process. The evidence is there to see on commercially released CDs. Where the signal goes to 0 dBFS (full scale) and stays there for four or more consecutive samples, that did not occur as a natural part of the waveform. It's a clip.

But if it makes music louder, and people don't mind, is clipping such a bad thing?

Well I wouldn't be one to stand in the way of market forces, if that's what people really want. But is it what they want...?

Here's a little demonstration that should convince anyone that clipping is a bad thing.

Here's a little track of fairly inoffensive music. The music is compressed and normalized, so that it hovers on and just below 0 dBFS most of the time. But it is not clipped...
(Apologies in advance for the distortions of the AAC encoding process)

music-unclipped.m4a

Now here is the same piece of music that has been raised in level by 6 dB. It's definitely louder...

music-clipped+6dB.m4a

And if I reduce it back down by 6 dB for comparison, it's really hardly any different to the original, is it?

music-clipped+6dB-corrected.m4a

Now here's the trick. I take the new version lowered by 6 dB. It's the same as the original except that the clipped peaks have been lost.

Then I subtract it from the original, leaving only the differences.

Here's what's left...

music-clipped-comparison-phase+6dB.m4a

Hmm... those clicks were what we were trying to get away from when we ditched vinyl for CD, yet they seem to be back again.

To be fair, these are not the exact clicks that are present in the 'mastered' version of the track. These are the peaks that are lost.

However, it's not only the peak itself that you hear, it's the sharp transition where the signal suddenly bends through a near-right angle. And these are certainly present in the 'mastered' version.

So if anyone ever wonders why music can often be tiring to listen to, this is exactly why. Mixed in with the music are thousands and thousands of clicks, just like these.

Of course, when the loudness war really is finally over, the record companies will be able to re-release their back catalog once again in unclipped versions...

Perhaps they know what they are doing after all?

Publication date: Monday June 29, 2009
Author: David Mellor, Course Director of Audio Masterclass