Mmm... The incredible magic a passive EQ can add on top of everything. We all love it, we all need it!
Well, here is the good news: In addition to its four flexible active bands, the xfilter 500 features a switchable fixed LC filter for polishing the high frequency range. The filter mainly consists of a capacitor and a coil per channel, but unlike the standard shelving designs, it has a slight resonance peak at 12 kHz and starts to fall of at 17 kHz.
This way, the saturation-like storage effect of the coil focuses on the area around the peak without pushing the complete high frequency spectrum too much. The inductors used in the xfilter 500 have their own shields to reduce outer influences like hum – without these shields, the coils would pretty much act like antennas for all kinds of unwanted noises.
Now you know what the 'Passive Massage' is all about: Opening up the top end of your signals by pushing just a single button!