Not including duplicates, I've owned or tried 40+ filters... Forty five if you include wahs.

I feel like I'm maybe forgetting a couple, but my list is below. I freely admit I might have a problem.
It's been a fair while since I've owned or tried some of these, but I'm happy to share thoughts if anyone is interested. I can't really promise a timely response given my current lack of engagement on Talkbass, but I'll try and check back to this thread specifically more often.
A couple random thoughts:
-
Doug John's "Chew On A Dog" (bass solo @ 2:22) track is 100% responsible for my fav filter of all time, the Pigtronix EP2/Bass Envelope Phaser. The EP2 is more flexible (particularly with the volume mod on mine), but holy hogs is it a pedalboard chonker. The smaller BEP is much easier to fit on a board. (Sidenote: I've got a patch on the source audio neuro that reasonably recreates this one)
- The 3Leaf filters are among my top favs
because they're on the darker side, though... I don't know I'd actually call them tame. I can get down with a nice quacky Mutron sound, but I've always gravitated more toward the darker, more greasy side of filter sounds. Reference: One of my favorite tracks of all time is Christian McBride playing through the filter on his ME-50B for
Philadelphia Experiment's "Ain't It The Truth." (bass solo @ 3:29)
- You're absolutely missing out if you haven't had the sublime experience of connecting an expression pedal to the Iron Ether Xerograph Deluxe or ladder filter on the Source Audio Artifakt. The Chancellor wah is very good at this as well. Put them at the end of the chain, and you can manually filter sweep
anything.
- If you like the Bassballs sound, do yourself a favor and see if you can track down an Ashdown Type 23. It's a
tri-band filter vs. EHX's two bands, and has a switch on the bottom which (according to the manual) "further varies the frequency of the selected ‘high’, ‘low’ or blended filter oscillation frequency."
- The Source Audio C4 and Spectrum do have that same filter engine, but when importing Spectrum patches on the C4 or programming them side by side, there is indeed a
slight difference in sound. It's not much at all, but I found I had to tweak settings slightly from one to the other to get the same result.
5sg.
My Top Favs
Pigtronix EP2/Bass Envelope Phaser
3Leaf Proton V4
Line 6 Auto Filter
Currently own
3Leaf GR2
3Leaf Proton V2
3Leaf Proton v4 (x2)
Ashdown Funk Face (MkI Stuart Zender version with the tube)
Ashdown Type 23
Dunlop Justin Chancellor Wah
Dunlop Mini Bass Wah
EHX Bassballs Nano
EHX Bassballs Russian
Iron Ether Xerograph Dlx (x2)
Line 6 Auto Filter
Line 6 Tron
Line 6 Asheville Pattern (Moog MF105M)
Pigtronix EP2 (with output volume control mod)
Pigtronix Bass Env Phaser (x2)
Source Audio Artifakt
Source Audio C4
Source Audio Spectrum
Owned previously
3Leaf Groove Regulator
3Leaf Proton V1
Aguilar Filter Twin (twice)
Ashdown Bass Envelope Filter
Barge Concepts Grinder
Digitech Bass Synth Wah
DOD FX25(b?)
Earthquaker Spatial Delivery
EBS Bass IQ
EHX Micro Q Tron
EHX Qtron+
EHX Enigma
Ibanez AW7 Autowah
Mojo Hand Analogue 442 Red
Mr. Black Fwonk Beta
MXR M188 Bass Auto Q (twice)
MXR M82 Bass Envelope Filter
Source Audio Manta
Subdecay Prometheus v1
Zvex Seek Wah
Tried but never owned
Boss AW-2 Auto Wah
Digitech Dirty Robot
DOD440
EHX Dr Q
Mutron III Haz
WMD Fatman
Xotic Robotalk 2
Want to Try
EHX Tube Zipper
Really Good Funky Puppy
Behringer BM-15M Resonance Filter
Ftelettronica Envelope Follower
Artisinal Meathead
Emma Discombobulater MkIII
Westco Pedals Grease Juicer
Solid Gold FX Supa Funk
Meridian Funkulator
3Leaf Wonderlove
3Leaf Chromatron