A multitude of maladies can afflict vocal takes and sibilance is one of the more pesky. It's the high-frequency hiss and spit of such consonants as 's', 't' and 'd', when unvoiced, which leap out of an otherwise tonally balanced vocal.
Obviously, the best way to avoid sibilance is not to record it in the first place (less obviously, don't write lyrics in the English language, more on which later). But with today's production preference of everything louder than everything else, even care at the capture stage oft does not obviate the problem because swathes of compression make sibilance stand proud.
When dealing with a hissy fit, you could engage in sidechain antics to actuate a compressor targeting high frequencies, but it's way more elegant to insert a de-esser, such as FabFilter Pro-DS, that's dedicated to the process and so needs very little set-up.
FabFilter's AU/VST/RTAS/AAX plug for OS X/Windows, with its 64-bit internal coding, MIDI learn, mid/side option and nifty interface, is also reckoned to be good for use on instruments - splashy cymbals and over-zingy guitars spring to mind - as well as a curative for transient zizz in a whole mix.
As mentioned, compression is often the culprit when there's a marked shift in perceived frequencies and we may have evolution to blame for this. If you listen to white noise (all frequencies at the same level) at a moderate level, you'll likely experience a hiss in the upper midrange between 3kHz and 5kHz and a quieter rumble between 300Hz and 700Hz.
The higher freqs are roughly in the range of a screaming baby and a more annoying shrieker attracts attention and so gets fed, which is quite important in evolutionary terms. As for the rumble, it approximates the snarl of a sabre-toothed mother. Honest. The above, of course, is conjecture, but study of a Fletcher-Munson curve does reveal that human hearing is sensitive to the two frequency ranges given, falling off below 100Hz, between 9kHz and 11kHz and above ~16kHz.
Compression attenuates transient peaks and make-up gain brings quieter frequencies forward. So, if you factor in human sensitivity to rumble and hiss, the frequency bands mentioned will be more prominent even though a spectral plot would show a relatively even spread (as ever, it's important to mix with your ears - meters can appear to fib).
To make matters worse, English is a comparatively sibilant language, but thanks to the British Empire and North America, it's spread across the globe to become the preferred mode of expression for lyric writers aiming to sell big numbers. And it's also fairly pleasant on the ear - songs in, say, Norwegian don't do so well, as you'll know if you've the stamina to withstand even one Eurovision Song Contest.
Hence, if aiming to rock in the free world (ie, not North Korea), you really could do with a de-esser. Has FabFilter got the balance of price against performance right with Pro-DS? In a word, yes it has. Describing the GUI as 'nifty' is understatement. FabFilter has a knack for devising slick interfaces and Pro-DS presents a prime example. Set up is a breeze and the inclusion of a meter to show what its algorithms are doing is immensely helpful.
As mentioned, you can use this plug on instruments or whole mixes, hence we've an Allround mode sitting alongside the self-explanatory Single Vocal mode. For a full list of facilities, burble along to the developer's product page - perhaps download the manual for an in-depth view, and/or cast an eye over this vid for a taste of what's on offer.
Naturally, the important thing is how it sounds. And it sounds nicely natural and transparent. There's none of that ridiculous lisping that can creep in when whipping out more strident sibilance (Toyah tribute acts may be disappointed, however). Transparency is important for a compressor of this type. While some producers pay a fortune to access the circuitry of a specific hardware compressor just to imbue a mix with analog sound colouration, 'character' is not something you're really after when de-essing.
Pro-DS does the job invisibly, as it should, and is mercifully easy to set up. For example, the mid-side mode, which enables you to target vocals running straight down the middle, is awesomely effective. Music-tech website MusicRadar notes: "We didn't expect to run out of space writing about such a seemingly simple plug-in, but we barely have room left to gush about the lookahead function, the great presets ... oversampling, the removed signal and sidechain auditioning, and the low-latency operation (in wideband mode)."
Music Tech mag, meanwhile, rescued a goth-rock song from death by reverb: "Because the song was already dark with little happening in the top end, we were worried that the [Pro-DS] might pull more frequencies out." It didn't, which is testament to the plug's mid/side facility by which the team managed to target the problem frequency and pull it down without knackering the rest of the mix.
There's the usual quibble about price and some may baulk at ~$190, but it's a very fair ticket when one considers the amount of time it could save during a mix. If any left-field possibilities crop up when experimenting on the next tranche of FellKlang, they'll appear on the appropriate Facebook page. And, of course, major updates to Pro-DS will be reported via the Facebook page for Doktor Fell @MuzoBlog - click the Like button there to get music-tech news and word of freebies appearing in your Facebook newsfeed. Make sure to Like while logged into a personal Facebook account, however. Likes from artist/band/fan pages don't count.
In all, FabFilter Pro-DS does the job of the must-have de-esser handsomely - quite literally, from a design standpoint. And for those of an esoteric bent, it's sufficiently flexible to help realise sound-design ambitions. The supplied presets are just the job for a fire-and-forget approach, while tweakers will enjoy the UI's flexibility.