Ok, we (Vlad and myself) finally found the time to set up a first version of an ultrasonic filter meant to address the problem. This is an alpha version, this means that detailed documentation is still missing and basically everything is potentially subject to change. Also, we haven't tested this plug-in in the wild yet, expect some hick-ups here and there... Win (installer) http://www.tokyodawn.net/labs/Ultras...installer).zip Win (no installer) http://www.tokyodawn.net/labs/Ultras...installer).zip Mac bundle http://www.tokyodawn.net/labs/Ultras...c%20Filter.dmg Behind the interface lies a very precise linear phase filter specifically tuned for the task of IMD optimisation in super-wideband processing chains (and playback!). It offers 3 simple parameters and a bypass button: - The corner frequency (specified as the point where the filter achieves 0.1dB of attenuation). - The filter slope steepness. - Amount (similar to a simple dry/mix function, but dB based). To be honest, I was shocked to hear the difference it made when playing back 96kHz masters. My monitoring chain certainly isn't the worst, but the effect of the filter is easily ABX'able for most "hotter" tracks. I start to feel like an audiophile salesman, so I'll stop here (lol, the tool is free, no worries ). But let me know your thoughts! Specifically, I'd love to hear your feedback for the following use-cases: - Using the filter in front of the final limiter during mastering. - Using the filter to improve playback quality of wideband systems/configurations. - Using the filter to remove/reduce excessive "out of band" content (for restoration).