From the EHX webpage for the Knockout…if you look to the right there is a link for instructions:

LOW Knob -The LOW knob is a volume control for the low or bass frequencies. The further you turn the LOW knob clockwise, the louder the low frequencies will be. The LOW knob controls the output volume from the Knockout’s 7-Pole Low-Pass Filter. The low pass filter has a fixed cutoff frequency of 85 Hz. The LOW knob is responsible for contouring the bottom end in relation to the total sound.

DRY Knob – The DRY knob is a volume control for the signal present at the Input Jack. The output volume of the dry signal will increase as this knob is rotated clockwise. Use the DRY knob in conjunction with the LOW and HIGH knobs to create your tone.

HIGH Knob – The HIGH Knob is a volume control for the high or treble frequencies. The further you turn the HIGH knob clockwise, the louder the treble frequencies will be. The HIGH knob controls the output volume from the Knockout’s 6-Pole High-Pass Filter. The high pass filter has a fixed cutoff frequency of 6.5kHz. The HIGH knob is responsible for contouring the high end to the total sound.

I love EHX, and I have been trying to decide on buying this pedal. It seems like it would be good for not only changing the brightness of your attack style. No one says what it does when low boosting is applied to a humbucker. Could be another good way to get a darker tone. I love the Metal Muff or a Big Muff boosted by a Tube Screamer. Nice dark dirty distortion. I was wondering if the pedal would give me a stomper for less of the same.

The thing I don’t agree about with the above post is the boosting. You claim a 6db to 12db boost to the selected frequency range, but that does not really make sense. From the description of the pedal, it seems like it would only cut. No boosting action was ever described. A 6-7 pole filter is a very steep corner cut filter. I am guessing essentially only affecting freq <85Hz for low and >6.5kHz for high. The fact that the pedal sounds flat with both tone knobs turned fully CW (zero cut) and dry fully CCW (no dry) supports this.

Now, if you ran a booster in front of this, that could be a different story. That sounds like a pedal I would buy. That would allow you run fully CW low and high freq filters at a significant boost. Dry would also boost when turned far enough CW.

Seems like a better pedal that way to me. Don’t know why they didn’t include a boost knob on it. It’s a bit subtle running like it is now.

I am probably all wet about the booster pedal. It would still just cut the boosted signal on the top and bottom ends, below the actual notes on the instrument. You wouldn’t be able to boost high or boost low.

Probably our friendly neighborhood EHX representative is right. It does what it says it does, changes the characterists of your attack. Makes an lp sound like a fender, etc. Not something I would appreciate much, personally. I’d rather just A/B my fender and my lp.

EHX usually makes very cool pedals though. It’s likely that this is right up somebody’s alley. The video included on the site is cool, but you better have good audio because the difference in the pedal settings is extremely subtle.

Still, this could be a solution for people who want a split coil but don’t want to mess with coil tapping. Or it could do the reverse for people who play single coils.