There are lots of topics of conversation regarding the best mixing practices, and these mixing techniques generally apply to a sub-set of genres.
I’d like to share with you some of the best tips for critical mixing that will certainly help excel your mixes to the next level.
1. High pass everything
In digital music production, a by-product of recording and processing is often a buildup of sub frequency content. This can happen from poor recording practices, over-working sampler devices, generating a synthesizer patch or simply applying distortion. Generally, sounds have a fundamental frequency meaning the loudest, lowest frequency generated and depending on the size, density, materials and shape of the instrument the fundamental frequency will vary. For instance, a kick drum produces a very low tone due to the size, shape, density and materials of that drum, thus, anything lower than the fundamental that appears in our recording or sample, are not important to the integrity of that sound and should be removed to create space for other frequencies.
For instruments such as cymbals and crashes, they don’t particularly generate a tone or a fundamental frequency, they are designed to spread their sound over the entire frequency spectrum, therefore, a fundamental frequency cannot be detected. Using a high pass filter on these a-tonal instrument until the fullness of the sound disappears will roughly mark the cutoff point for the filter itself.
2. Limit in stages/groups, especially on drums
Transients are brief spikes in amplitude and are the primary culprit for a loss in headroom. These brief spikes in volume will register a higher peak reading on the meters than a sound without transients would. Drums are riddled with transients as that is their identifying characteristic and sometimes more than one drum may be triggered simultaneously causing a sum of two transients. Simply offsetting transients by using a track delay of a few milliseconds OR by physically shifting the audio a few milliseconds can offset these transients causing very little to no exaggerated summing of amplitude.
If track delays and offsetting the transients are not an option, you may group these combined transients into a common channel output and apply a limiter to the grouped tracks. This will take care of the combined transients by shaving off the biggest spikes and keeping your drums levelled at a common peak level.
3. Remove overlapping audio tails and time your reverb tail to the tempo
Low amplitude tails of samples, synthesizers and even lasting effects such as reverb tails and delay copies can ultimately add up and raise the noise floor reducing dynamic range and potentially reducing clarity of other sounds. For example if you have a long crash sample that is 4 bars in length and you are triggering this samples every 2 bars, you will have a pre-existing piece of the previous crash layered in with the newly triggered one, this will create a slight reduction in headroom if any number of tails are combined. Simply delete the overlapping tails that continue through to avoid unnecessary summing of audio.
Another method of controlling excessive reverb tails is to time the decay of the reverb to the tempo of your track. If the tempo of a track is 120BPM, this means that every beat or ¼ bar is 500 milliseconds. Knowing the length of 1 beat, I can now use simple arithmetic to calculate the length of 2 beats, 3 beats, 1 bar, 2 bars and so on. If this snare drum is triggered every 2 beats, it is a smart idea to time your reverb decay to end before the next drum, or else reverb tails will combine, sum and diminish headroom. In which case, my reverb decay time should be 1 second to ensure the end of the effects before the next one is generated.