The 10 Biggest DAW Mixing Mistakes
A click caused by a moment of clipping (an overload at the input of the recording) will have a flat-topped look in the waveform display (see fig. 3). You may be able to tame this by selecting that one tiny spot and applying a low-pass filter to it as an audio edit.
4. Over-Compressing The Master Bus.
Pop music mizes tend to be boosted to as high a level as possible. Adding a compressor to the master output bus (see Fig. 4) is a good way to push up the perceived loudness without adding distortion. But too much compression can sound very artificial. For example, a loud guitar chord might cause the compressor to jump into action, which might cause an important drum hit or vocal syllable to get swallowed.
Over-compressing the master bus by setting the threshold too low or the compression ratio too high will cause sustaining sounds such as a reverb wash or synth pad to duck behind every loud event, such as a kick drum hit. This highly artificial sound is called “pumping.” Though useful once in a great while as a special effect, generally it’s best avoided.
If you spend some time adding automation data to smooth out level changes in individual tracks, you won’t need to use as much compression on the master bus. That one overly loud guitar chord can be pulled down with a few mouse-clicks (see Fig. 5).
If you use a multi-band compressor on the master bus, you can be reasonably sure a loud vocal note won’t cause the kick or bass to duck, or vice-versa, because each frequency range is compressed separately. But that can lead to other problems. There is often less audio energy in the high range of the mix, so that range may be compressed less or not at all by a multi-band compressor. This can change the tone color of your snare drum by causing the highs to pass through without compression while the compressor backs off the main tone. If the snare starts to sound brittle instead of beefy, multi-band compression may be the culprit.