I was mixing a track today and there was very nasty hi-hat bleed in the top snare mic. Usually I let it pass but this was simply too much and I started tweaking gates and expanders with not-good-enough results. I started thinking "there has to be a way..." and here's what I ended up doing:

- Copied the snare drum track to another track
- Reversed the phase of the copied track and set it to the exact same level, the result of course total silence (my intention)
- Now that the hi-hat was dead silent I needed to bring in the snare...
- I compressed the sh*t out of the phase-reversed track and VOILA !
- The compressor removed the snare from the phase-rev track which brought in the snare on the original track. The hi-hat was still phasecancelled.
- Tweaking the releasetime of the compressor gave control over the sustain in the snare and the attack was set very fast to remove the transient of the snare. I compressed a lot, maximum ratio and as much gainreduction as possible on the snare without affecting the hihat.
- Some fine-adjustment and I had the snare only, not the hi-hat !

The result felt a lot more musical than any gate or expander I tried. Don't know if it's an old trick, but it worked. Worked very well :)