WOW. A HPF that works ...just like every other HPF... but in a special way... Yeah!. It's time to go to sleep
For what it does, I thought it was free.... You can easily (and also fast) use Pro-Q/Pro-Q2 or any other EQ with mid/side capabilities, hi-pass just the sides then save the preset and you just made your own "Sidefilter" instance which you use just as quick and easy as the "mr.Pricy" above.
http://audiosex.pro/index.php?/topic/17227-a1audio-updates-a1stereocontrol/ < posted earlier does the same thing, is FREE, but offers less control. There's also Nugen monofilter which offers a nice visualization of phase.
Side Filter updated to v1.2 ■ 2017.04.15 Side Filter is an High Pass filter focused on removing bass frequencies from the Side portion of a stereo mix. This filter is very useful to tighten up the low end of your mix or to help you prepare a vinyl ready master. From v1.2, Side Filter includes Low Filter: a simple yet elegant general purpose High Pass filter. Side Filter Features: Butterworth and Bessel filter designs. HPF Frequency range: 12 steps from 12Hz to 1kHz. 12db and 24dB slopes. Side solo. Low Filter Features: Butterworth and Bessel filter designs. HPF Frequency Range: 12 steps from 12Hz to 1kHz. 6db, 12dB, 18dB and 24dB slopes. Read more here Last edited: Apr 15, 2017
Side Filter updated to v1.2.1 ■ 2017.04.18 IMPORTANT - Licenser Bug Fix We have updated Side Filter to v1.2.1 fixing a serious issue with the licenser invalidating a legit license file. Unfortunately, this update REQUIRES the generation of a new license file. To update, download the installer and (most importantly) a new license file from your User Area. Last edited: Apr 18, 2017