3. Dealing with plosives
Ideally mixing engineers will deal with plosives on their end, but not all engineers are that discerning. A sloppy mix-engineer might have not thought to address them (I’ve had a few such projects recently). Or, you could be mastering a live record, where all sorts of variables are at play that might make editing plosives unfeasible.
Whatever the case, if you have a module like RX’s De-plosive, you can reduce plosive issues with minimal effect to the overall sound, especially in an acoustic mix before drums come in to impact the low end.
This doesn’t mean, however, that you can just set-and-forget the plosive module and expect effortless results. Sometimes, for a proper job without artifacts, it makes more sense to look at the spectrogram, find the offender in the frequency spectrum, and from there, switch to a tool that grabs specific frequencies, such as the lasso or the paintbrush. Now you can highlight the most heavily shaded parts of the spectral graph during the plosive—for these are the biggest offenders—and run De-plosive in a frequency dependent manner, or Spectral Repair, if you think that might do a better job. More on Spectral Repair later.
4. Removing unwanted distortion
Every once and a while you get a project that has audible distortion. It could be undesirable clipping, or it could be something else entirely. All you know, from your vantage point, is that the distortion is undesirable to you.
But it might not be undesirable to the band. Your first move is to call the point person on the production team and ask if that distortion is intended. If it isn’t, your next move is to contact the engineer, if you can, and negotiate a better mix. This option isn’t always on the table, so luckily software like RX has ways to fight this distortion—tools which can, to some extent, repair mangled material.
A lot of the time the De-clip module does the trick, even if the material isn’t clipping per se. The process is relatively simple: highlight the passage that is distorting, have the module suggest its processing, audition the results, and tinker to taste.
Repairing distortion is best done in specific, sporadic places, and not across passages of more than a couple of seconds—and that’s speaking liberally. You may have to spend a bit of time to get all the nasty bits, but it’s still worth it.
Sometimes, the distortion is more of a high-end crackle than a clip. Here, the De-crackle module, tuned to attenuate high-frequency distortions, can often work.
5. De-noising less-than-optimal conditions on a solo acoustic mix
Sometimes acoustic material isn’t recorded in optimal spaces, and here, it might be best to de-noise a passage. Ideally you shouldn’t have to implement a de-noise module for too long a time—a solo acoustic introduction to a fully fleshed out song, for example, could be all you need. In general, try to air on the side of caution, because the ear is far more forgiving to the sound of noise than to noise-reduction’s usual artifacts. But give it a go if necessary.
When it comes to de-noising, it might be better to implement this process after EQ and compression, because these processes can change the quality of the noise. You may have to commit your digital processing before implementing noise reduction if you’re working entirely with software. If you’re using outboard gear, I find it’s best to denoise after the capture stage. Ultimately, the decision of when to de-noise is your call.
6. Dealing with problems in the left or right channel
Recently a mix came my way with unflattering distortion on one guitar part in the left channel. It only occurred in one part of the tune, so I checked with the band, and yes, if I could do something about it, that would be great.
So I loaded the track in RX, found where it happened, and took it the distortions with the De-clip module—but only in the left channel, and only for a small duration of time with each pass.
This is what I find wonderful about audio restoration tools: the ability to fix something that exists solely in either the left or right channel, something that would necessitate a time-consuming creative solution in yesteryears, is very easy to fix now.
And it’s not just distortion: clicks, bits of unnecessary noise, and more can lurk in one channel or the other. In these cases, why would you process the whole mix when you can actually delve into the corners and excise the issue with a more surgical hand?
7. Rebalancing the instruments
Mixes come to you in all sorts of states. Ideally, you should have a great relationship with the mixing engineer, be able to call that person on the phone and say, “hey, the balance of the bass is off,” or “did you mean to have the snare drifting towards left?”
But this discounts the unfortunate politics that go into record making. Say the mixing engineer was not only the producer of a track, but was involved in marketing the material. Say you respect that’s person’s ability in the producing and marketing arenas, but the mixing is badly balanced. To tell that person their mix is somehow inferior might be to shoot yourself in two different feet if you wanted to work with them again. You don’t want to aggravate a political situation and make your artist’s life harder.
Here we may have to do a measure of “rebalancing” ourselves. Most of the time this is not—repeat not—an audio restoration task; if the vocal doesn’t feel centered, and we need it to feel centered, simple panning or balancing tricks within the DAW can sometimes help us.
However, I do use audio restoration tools every once and a while to accomplish rebalancing. Perhaps the problem is relegated to a frequency band, in which case RX’s ability for frequency-specific processing across all its modules is a boon. Sometimes the Mixing module can redirect the energy in a more natural—and more nuanced—way than the panning tricks of a DAW.
Now, with RX 7, you’ll note the new Music Rebalance module. This is an interesting tool, and one that can do some good if used with a subtle hand (as is the case with most mastering tools). Say the all the drums are a bit too soft, or too buried; you could use the rebalancer in small degrees to raise the drums just so. Alternatively, you could isolate the drums drastically, bounce them, and export them as a parallel track into the session. However you would need to be very, very careful. The levels would need to be low (lower than parallel compression in a mix on even the subtle side), and, you would have to make doubly sure the smearing or artifacts trade-offs were worth it. These issues would have to be so unnoticeable as to not cause harm, while still justifying their use in the first place.