You’re most welcome. Try not to worry about it, these processes will become second nature with a little practise and understanding..!
Make sure you’ve set the dry signal to -inf dB and the wet signal to 0 dB at the bottom right of the FX unit page. You only want to hear the processed signal and not the unprocessed signal; with mix->return you were combining the two, which is why you were experiencing feedback.
If I were you I’d start with one unit inserted on the group (saving you some FX slots) and see how you get on. If you still end up with extra uncontrolled sibilance, you can look to inserting another unit directly on the offending channel.
I’ve purchased the de-esser but I haven’t really had a need to use it yet, so I have no direct experience to share. But, like the other FX, I would probably start out by trying out the factory presets in the library and adjusting the controls from there while listening to the results. Your idea should work as well — the only thing I would do differently is start with higher reduction and response values in order to clearly hear it working while sweeping the frequency.
Remember that if you PAFL an input channel, you will be grabbing the signal long before it hits the group with the FX insert. The best you will be able to do to ‘solo’ the de-esser in this application will be to PAFL the group, which should give the 100% wet signal from the de-esser if configured as mentioned. Note that if your “Input to PAFL Source” has been set to “Post Preamp” then you will need to change this to any other option in order to pick up the signal after the insert return (see page 71 of the reference guide).
Have a bit of a play around anyway and come back on afterwards to describe how it went and whether you have any further questions!
