If you were recording an ambient album

[Ben Lesser]

Which effects would you have in your setup?

Reverb is an obvious choice.

I'd say an octaver would be very useful for creating higher parts, or deep swells, but I couldn't think of what else would be useful/necessary.

[WhiteNinja]

A delay capable of self-oscillating and modulation, a Pitch-Shifter, maybe something like a POG. All those controlled with Expression Pedals. A loop station would be quite handy too.

[Epitaph04]

Whatever Devin Townsend uses.

[Knettgummi]

A laptop...

Edit: More to the point: I've played a bit of ambient/electroacoustic music, both live and recorded, solo and in a duo/group, and I tend to change my set-up from time to time, since it is mostly improvised music. On the times where I've played bass in these contexts I've typically run it through a grain delay (really cool stuff), regular delays and crazy amounts of reverb, along with some other varying stuff.

As you mention, reverb is pretty much a given, which to me is just as good a reason to try and do without it. I don't know how "traditional" ambient sounds you are going for, though.

[phatbass]

For live use? Boss DD7 - tap tempo, reverse, does the psych self oscillation thing, looping/sampling...

[Knettgummi]

Yep, DD7 is nice - sampler is a must, the DD7 does a decent job of this. POG has been mentioned aswell - I'd go with the full POG2 if possible, for that "organ"-like sound and adjustable attack/decay. An analog delay that lets you insert effects in the feedback loop could be cool (combine with some pitch shift, for instance). And make sure to have a reverb that does really large halls; preferably one that goes to 100% wet signal.

Personally I like to do this kind of stuff with a computer, through ableton live and max/msp - it makes for a more flexible and ultimately cheaper and more portable setup.

[BassBrass]

an ElectroHarmonix Freeze would be most useful. A volume pedal into effects. Two amps (or add a small remote one) for stereo performance, assigning different loops to, etc.

[Josh Pelican]

Delay, reverb, and chorus.

Personally, when I write ambient music I like to focus on the guitar more and use as many effects as possible. Six different delays, numerous reverb settings, etc.

[AlvarHanso]

Besides the POG2 mentioned, I'd use something with LFO and probably tap/tempo, a phaser (Source Audio BEF Pro would be my choice there using a phaser setting with LFO and tap/tempo), reverb and delay, as well as either chorus or Uni-Vibe/Leslie emulator.

[Swimming Bird]

I tend to have a kitchen sink approach when it comes to ambient. That said, an ebow and a loop station are my usual necessities.

[mouthmw]

I'd also add fuzz, maybe a scooped sounding one, like muff, something not overly aggressive in mids, for that hollow but rich smooth texture. But maybe that's more in the shoegaze territory. I do love the atmospheric tremolo picking with fuzz though, check out Wolves in the Throne Room - Dia Artio. Sweeet.

[DeltaPhoenix]

Roland GR-55

[groooooove]

korg AX3000B would have it all covered- its an ambient machine, with all those verb/delay/mod settings that absolutely rule, and are super user-controllable in the wackiest and most amazing ways.

[Shish]

Pitchfactor, Boss RE-20 and Ernie Ball volume

[MSUsousaphone]

Man....grain delay is pretty freaking cool. So there's nothing outside of laptop programs that are capable of doing that? Like there's no pedal or combo of pedals that gets that sound?

[Oneirogenic]

The absolute bare minimum I would use for ambient is delay and reverb. You can cover a lot of ground with those. A phrase looper is a insanely useful for building soundscapes. After that any kind of modulation, pitch shifting/harmony, and most kinds of dirt. Layering reverb drenched fuzz swells one note at a time with a looper is far more effective than chords and sounds like a synth more than a fuzzed bass. Experimentation is key. I find volume pedals, ebow, and other unusual sound making implements to be useful tools for making soundscapes. I could go on forever about making ambient music....

[caeman]

fuzz, flanger, phaser, tremolo, three modulating delays and a looper.

[bassistjoe93]

Uni-Vibe, I use that in my regular set-up, slight reverb, a nice delay unit and the effect that reverses whatever you play.

[FaithNoMan]

Everything here has Re-20 on it, excluding the drums. So, guitar and synths, basically:

MP3 Player SoundClick

The 2nd half of this has Re-20 all over the synth tracks:

http://www.soundclick.com/player/sin...&q=hi&newref=1

Another good effect is the Mid-Fi Pitch Pirate - it does a good job of making a synth track(or anything else, really) sound like it's being played on a lagging tape deck.