lagerfeldt wrote:A third solution is to make a duplicate of your vocal track, including all processing, but insert a Utility > Gain plug-in at the end of the chain and flip the polarity (called phase invert in the Gain plug-in). Then use the scissors or marquee tool to remove everything but the sibilant areas. Use volume automation on the remaining regions to control how much de-essing you want.
The theory behind the above method is that you're simply phasing the sibilance out. This method does not require any de-esser plug-in in the chain.
ojan,
This particular method lagerfeldt describes is the most transparent and I use it for a lot of restoration work. Here's an enhancement to this technique that improves on it further, and avoids most of the editing...
After duplicating the track and reversing its polarity, place a Linear Phase EQ, followed by a Noise Gate, in the last inserts of the dup track. Solo this track. Bypass the gate for the moment.
Set the EQ with a bandpass or highpass around the sibilance. Keep the slope gentle, don't brickwall it or there'll be too many artifacts. You want to hear the sibilance nice and loud but not worry about eliminating everything else.
Enable the gate. Set Attack, Hold and Release to 0 and add 3 or 4 mSec of lookahead. Start by adjusting only the Threshold, Reduction and Hysteresis and try to isolate the sibilance completely. Use the Side Chain filter if the gate is still triggering on other frequencies you want to keep.
Now add the original track to the mix to allow the gated sibilance to cancel the original. You can tweak the gate's Attack, Hold and Release if needed but you shouldn't have to. Just be careful as you can add nasties to the sound with weird settings.
The key benefit to this is that you won't be reducing the level of lower vowel frequencies that may be concurrent with the sibilance. It avoids a lot of region editing too!
edit: Note that you can always tweak the linear phase eq for where and how much sibilance gets removed, but remember that you don't want to remove too much of it as you need some to keep the vocals intelligibility strong in the mix.