ToneBoosters has released TB Sibalance which they describe as providing top notch sibilance processing using matched-filter technology for ultra-transparent de-essing. Here's what they have to say about it:
De-essers can be an evil necessity. Vocal recordings may be too sibilant requiring de-essing (or excess sibilance removal), but most de-essers come with very clearly audible drawbacks as well. After de-essing, vocals may sound muffled, the 's' may sound more like an 'f', or even worse, the operation of a de-esser manifests itself as a clearly-audible time-varying filter. TB Sibalance provides very powerful tools to reduce excess sibilance in a minimally invasive way. In contrast to conventional de-essers, TB Sibalance uses so-called 'matched filter' technology to only process those frequencies that are causing excess sibilance, while leaving all other frequency components untouched. The result of TB Sibalance will therefore sound cleaner and more transparent than that obtained with other de-essers.
Yet another de-esser? ToneBoosters already provides two de-essers; the TrackEssentials de-esser with zero latency, and an integrated de-esser in TB Evoke. Both plugins have their own merit, but we thought we should be able to do better. New TB technology, such as ultra-transparent gain processing and tonal decomposition (as featured in the recently overhauled TB BusCompressor), the matched-filter technology from TB Evoke, and a couple of new innovations together result in a much better, powerful and transparent de-esser.
De-essing like a compressor You may see a very familiar input/output curve in the screenshot that looks like a compressor. In this case, the input/output curve does not relate to level, but to (excess) sibilance. Sibilance is a property of audio that is largely independent of level; signals sound sibilant if there is a relatively large amount of signal energy present in the sibilant range (typically 4-11 kHz) compared to the overall level. Nevertheless, TB Sibalance allows control of sibilance by means of a threshold, a ratio, a soft knee, and a range parameter; much like a compressor. Of course, a dry/wet control is included as well.
Algorithm fusion TB Sibalance has three algorithms: (1) a broad-band de-esser, (2) a band-limited de-esser, and (3) a matched-filter de-esser. The latter will create a filter dynamically that only reduces sibilant frequencies while leaving everything else untouched. In contrast to many other de-essers, these algorithms can be fused on a continuous scale. Do you want 60% of de-essing using a band-limited de-esser, and the remaining 40% using matched filter technology? Just set the algorithm slider to 1.6 and it is all set. Moving the algorithm slider from 0, to 1, to a value of two seamlessly fuses the broad-band de-esser, the single-band de-esser, and the matched-filter de-esser.
Tonal component sensitivity In many practical situations, vocal sibilance consists of noise-like signals that one would like to suppress. Tonal or voiced signals, on the other hand, are often better left untouched. Conventional de-essers cannot discriminate between noise-like and harmonic signals – they simply measure energies. With TB Sibalance, the relative contribution of tonal components to the measured sibilance can be adjusted so that the de-esser works much more accurately.
Mid/side processing and high-quality modes If a bus signal or full track needs de-essing, great results can be obtained by de-essing the mid channel only (this is typically where the vocals are), while leaving the side signals untouched. Mid/side mode of operation is available on TB Sibalance, as well as a control to engage a high-quality mode.
Signal level dependencies It can be very desirable to reduce excess sibilance for relatively loud parts of a track, while leaving less loud elements untouched. The 'level threshold' control of TB Sibalance influences how sibilant low-level signals are. Basically, if the input signals approach the threshold set for level, the measured sibilance will gradually be reduced, and hence the amount of de-essing will become more subtle or even absent.
Processing of full mixes Ideally, a sibilance tool is sufficiently flexible to also process full mixes, for example to catch excess esses in a mix, or simply to reduce the mix's harshness. This is why you'll see controls to change the 'voiced' frequency range analysis; for mix processing, these can be set to cover almost the complete audible frequency range.