Scalpel is an early attempt at a ‘surgical’ EQ meant to sound better than using a DAW’s internal DSP-cookbook EQ. It sort of almost works.
What it does is, give you three very narrow and intense beams of resonant filter, coded the same way ResEQ is coded. Instead of building a sound entirely out of these beams of resonance, Scalpel just gives you the mix and the three added filters. They have limited range and are happier in the mids and highs (but not the super-highs), and they’re not awesome at cutting, just at boosting.
They don’t sweep well by automation, either, because they recalculate their convolution kernel one bit at a time to avoid smashing 2007 CPUs too hard at once.
Lastly, I don’t see it as a mastering EQ, because it simply processes too much and does nothing to accomodate that necessity (newer plugins with a lot of processing, such as ToVinyl, take measures to retain tone and not just drown in a million calculations).
Have fun playing with Scalpel, and don’t cut yourself too bad ;) Scalpel declares one sample of latency.