Finally got off my butt and put together a little filter shootout that I've been wanting to do for a while now. Filters are the MXR M-82, WMD Super Fatman, and a 3 Leaf Groove Regulator modded to add a wet/dry blend. GR should be similar to a GR2 minus the gain trimpot. It's so hard to actually compare effects with the usual "let me turn all the knobs on this thing" reviews; I've taken the opposite tact. I set each pedal for the closest I could get to "my sound". These things can all get different sounds and YMMV, but it will give you a much better feel for the subtle differences between each of them.
I have clips of each of them with three different grooves: finger style, slap, and octave+filter. I chose settings more or less based on the sound of the finger style groove and left them there, just as I would for gigs using a single filter. In some cases I could have improved things a bit on the later grooves with some knob tweaking, but I had to limit the variables.
Note, these are all 9-volt powered with a wet/dry blend which are base requirements for me (darn you Q-tron!). I generally find slap through a filter without dry signal mixed in is too thin sounding.
And no railing on my playing
Here it is: http://www.youtube.com/watch?v=3LpZ0czQOPc
This was actually pretty informative for me as well. Even though I've had each of these around for several months, I've never compared them this systematically. Here's what I got out of it:
Finger-style: Groove Regulator probably my fave, cool analogy sound. Others do all right, but Fatman>M82.
Slap: I dig the Fatman the most, nice full, clean, sound. M82 sounds ok and the high end would probably cut through the mix better and dialing back the sensitivity a touch would've beefed up the slaps some. Groove Regulator has a strange warbliness to it that I don't love.
Octave+Filter: M-82 has a nasty sound that I'm digging more than I thought I would. Octave fills out thinness from the bandpass and the accentuated high end would cut through a mix well. GR sounds good too. Fatman would've sounded better with a tweak to the threshold. Is there a filter that doesn't sound good on top of an octave???
Range control: limited, I'd like more options than Hi/Lo
Attack/Decay control: best of the group (has both!)
Resonance control: A little lacking, but I don't need over-the-top
Gain/blend control: Lacking in stock GR, GR2 seems all set
Spencer's going in the right direction with the GR2. Only thing I think I'd miss on the GR2 is a more control over the filter frequency range. But I don't dig the strange artifacts in the slap sound. Must give a shout out to Spencer for fantastic customer service though. This pedal is easy to set and gig with.
Range control: seems like top end of filter range is fixed while "decay" really controls the bottom of the bandpass range (at least to me). Decay helps dial in some pretty cool sounds, but the bandpass can sound thin depending on sensitivity and blend.
Attack/Decay control: none as I understand it. No real control over "quackiness".
Resonance control: not available
Gain/blend control: Best of the group, both overall gain and blend controlled externally
M-82 is an all around solid but not stellar performer and easy to set and gig with. Due to ease of use and ability to cut in a mix and just sound nasty with my octave, it might have weaseled its way back onto my board.
Range control: great, has 12 options
Attack/Decay control: attack works well to dial on quack, but no decay control and it's pretty dependent on threshold setting
Resonance control: great, fully variable
Gain/blend control: external blend with internal gain pots, good, but internal pots are bit of a pain
Super Fatman -- you can tweak just about any sound you want out of this thing, and it's very full and hi-fi sounding to my ears, though it does introduce a bit of high-end hiss. Alas, it has just as many knobs and switches that I will never touch, not to mention the red text on the face blends in with the purple background, so forget about reading it on stage. I like it, but it might have to stay at home for recording.
IN THE END
In the end, each of these pedals has its ups and downs and they've been continually rotating on and off my board for months. I think I understand them better now, but I still don't know if I can get rid of any of them. Such is the way with filters, I fear.
I like the sound of the Q-tron in clips, though I've yet to actually play one. I just don't want to do 24 volts and the micro Q-tron doesn't have a blend, and I'm not going to add a blend pedal either. I'm excited about the Mutron-type pedal Spencer at 3 Leaf is working on, might be the next addition to the herd. Wonder if I can get a blend on that...
Happy hunting. Hope some of you find this useful or interesting.