Drumatom is a standalone application for 64-bit Windows and Mac OS X that can analyse a group of multitrack drum parts and, using "Advanced Audio Analysis - A3" technology, separate the sonic wheat from the chaff within each one, enabling you to magically dial any spill out entirely. It's not a gate and it's not a filter; neither is it a triggering tool.
For a mix engineer, there's nothing worse than finding yourself lumbered with a drum recording that's all but unusable because there's more hi-hat than snare in the snare mic. Sure, you can apply a gate so that the signal is silenced in between snare hits, but that doesn't stop you getting an obnoxious burst of hi-hat every time the snare and hat are struck together.
What we really need is some uber-smart software that can analyse multitrack recordings and magically remove the leaky elements altogether, leaving them sounding like perfectly isolated parts with no spill. Enter Drumatom.
To use Drumatom, you simply drag some or all of your drum tracks into the app, automatically creating a 'Group'. You then have to assign each track a drum channel type (snare, kick, hi-hats, overhead and tom (high, mid or floor) - if your files are named descriptively, this will be done for you.
Helpfully, you can create your own set of track name abbreviations in the preferences to make sure the auto-assignment always works how you want it to. The whole group of tracks is then analysed, which can take up to one and a half times the duration of all tracks together.
With that done, the Focus knob on each drum track reduces the leakage into that channel, while the Fine Tune knob mixes back in a bit of the spill for a more natural sound, and the suppression meter shows the spill reduction.
Most of the time, the results are nothing short of spectacular. In our tests, a hi-hat with a lot of snare and kick in it lost all sign of any spill, with no perceivable artifacts. Similarly, our kick drum retained its transient and natural decay but completely lost the background snare.
The snare proved a little harder to clean up without some tonal loss, but the result was still impressive considering the complex frequencies involved - it fared better with fewer tracks in the group.
The process was less effective on toms, as they're hit less frequently and thus don't give as many clues to the algorithm process. In their case, a gate or manual editing may still be best.
With spill reduced, your processed tracks can be exported and flown into your DAW. While the whole process may sound long-winded, Accusonus says a plugin version isn't currently possible because of the intensive DSP involved and the way the tracks are cross-referenced.
Hopefully, they will eventually find some way of making it more DAW-integrated, as not hearing the drum tracks in the context of a mix makes it hard to determine the amount of suppression required - all files maintain phase coherence, though, so you can mix them with the unsuppressed tracks in your DAW to get the right balance. You can also save analysed drum groups for easy revisiting if necessary.
Drumatom really does successfully isolate direct signal from bleed with very little in the way of side effects. Its standalone operation will put some off, but for seriously alleviating bleed issues on dodgy drum recordings and creatively controlling spill on good ones, this is the only game in town.