The problem I find with Chorus pedals is that they are really designed and intended for guitars. On bass there isn't much in the top end there to start with and needs really heavy settings (compared to a guitar) to hear anything worth while. The classic Chorus sound robs a lot of low end too. If you try to mix in the bass original signal to retain the low end, then you lose a lot of the chorus' wetness effect.
Over the years I've had a lot of great chorus pedals. I rocked a Strymon mobius a long time and I found that I wasn't getting what I wanted out of the Chorus patches. I wasn't getting the sound I was after.
After a lot of research, I went down the Source Audio route. Their three modulators all share the same downloadable patches and are identical except for the baked in physical knob assigns (bit of an over site there SA). I went for a Lunar as it offered more useful controls than the Gemini (mix and tone? Really?) and the Mercury. I've had it about a year and my conclusion is the hardware is amazing and sonically superior to the Strymon Mobius. To the point, I would say that this digital device sounds more analogue and a lot of analogue pedals. The stock phaser and flanger sounds are top drawer out of the box, no edits needed. However, the Chorus' effects...less so. But it's not a fault of the device or a fault of SA's coding. They are pretty close emulations of the source pedals, it's just that those pedals weren't great on bass to start with. CE-1, CE-2, Dual and Quad Chorus' seem to struggle on bass, and are very difficult to get them wet enough. There is so little treble on bass that there's much to affect. There needs to be less parallel blending (great for guitar...awful on bass) and either a fancy low retain mixer (mixer in the low end) or a solid bass boost control. The great thing about the SA Modulations is that you have both (and a lot more) in the neuro app. I've basically spent the last year tweaking my chorus models to work in a fashion that really works for bass. The SA's 4 band semi-parametric EQ allows a lot of tweaking. Plus you have a low retain and mix control. You also have 4 chorus models to choose from, an optional tremolo and you change the modulation shape too. If anything was going to nail Chorus on Bass, the SA gear was going to be my best shot.
So I've settled on a pair of patches, one based on "Phrs82"' "Dimension M ish" patch. It's a classic Flange / Chorus model (think CE-2) but pretty much nails the lush and expensive sound that I was looking for. I also found that a bit of low retain and bass boost helped the low end a lot and a massive 16db boost at 3Khz seemed to add all the lushness I could want (in fact this seems to be the magic source for Chorus on bass). The other patch is a modified Nikopappas Purple Rain patch, based on a Quad Chorus model. Again, I applied the low retain, touch of bass boost and the magic 16db at 3Khz and voilla...a Chorus that sounds great on fretless, great on it's own, stacks with an OC-2 and / or Gated Muff. I finally think I've found what I've been looking for. Patches will be on the Source Audio Cloud later today and I might even get around to recording some sound bites. "GMC Purple Rain" and "GMC - Mild CE-2", if you search under gazzajagman you should find them on the could easily enough.
