Well Mark, I've been where you are, minus having the option to play with the OS. Someday, I'll have one. Someday....
Still this is what I've learned. I'm a synthaholic, and being slightly brain damaged (perhaps from too much synth), I've kind of figured a way to create synth sounds.
In basic sound terms a synth is a combo of some kind of fuzz and an envelope filter. There are other things that you can do to help flavor this soup up. You can add octaves into the mix, flanges, and even different options for trigger sensitivity and gates for when the sounds shuts off. There are some all in one boxes that do a GREAT job at this. One is your OS, others are the Akai Deep Impact, the Korg G5, and many others that aren't quite as good as that. I've recently been dabbling with the Copilot Orbit and that's an impressive little pedal too. Still, with all that said, you can have an infinite amount of possibilities if you start buying pedals with the thought in mind that if you get a pedal for each of the elements of a synth, you're going to have more options for creating synthy sounds. This is what I do.
First let's talk a little about my set up. I run my basses (mostly a Warwick Corvette $$ 5vr) into a BOSS DD-3 delay -> BOSS BF-1 flange -> Ampeg SVP-BSP -> 1000W Carver Power Amp modded to Mono -> Cabs.
The SVP-BSP is a split channel pre-amp with one channel being "clean" and other channel being "dirty" and you can run them individually or as a blend. Each one of those channels also has the option for running a FX-Loop. Since some pedals might have a cool sound but crappy tracking, I ALWAYS run my clean sound in the mix while my FX-Loop resides on my dirty channel. Some effects work better globally (DELAY, and FLANGE) so I run them in front of the preamp because it sounds crappy when one channel is flanging or delaying while the other channel is unaffected.
Here's my FX-Loop running through the dirty channel.
Here's a picture of my board.
On the top right of the photo, you'll see my Boss DD3 and BF-1, those as I mentioned are not part of the loop. The rest of the mess runs like this. It starts with the EHX-Bass Micro Synth -> MoogerFooger LPF101 -> Boss OC-2 -> Boss GE7 -> EHX Q-Tron -> Digitech Bass Synth Wah -> Boss SYB-5. Of course, I don't run them all the time but I've found that there are some cool synth "sections" in my board that I like to run.
The first synth section is my EHX-BMS->MoogerFooger LPF101. I basically run the BMS as a fuzzy octave that feeds into the MoogerFooger envelope filter. There are literally hundreds of options within these two pedals. It's all analogue, if I recall, and I can always quickly twist and tweak into something really interesting here. The BMS is kind of a synth in itself, but I'm not totally stoked on the sound by itself, unless I play in the higher parts of my bass. I find that I use it more as a fuzz, octave combo. Once I set the octave with the amount of attack that I like, I set the fuzz (square wave) with the amount of delay and release that I like. Then it's off to the MoogerFooger which can be real fun when I run an expression pedal attached to the cutoff and resonance knobs (recently I have not been doing this though). Here is a link to one flavor this sound.
http://soundcloud.com/downanddirty/niney-dub-down-and-dirty
I kick it in at the 3:12 mark.
Next is a fairly new little synth section, but it's showing a lot of promise. It's my OC-2->GE7->EHX Qtron. The OC-2 is the old classic octave pedal. The 'fuzz" or dirty sound is simply the distortion/overdrive of my Ampeg SVP-BSP, blended with the OC-2 pedal. The GE7 is a new addition. Funny, because I was thinking about dumping this pedal, but I noticed that other guys around here were using it as a kind sound shaper, so that's how I have it functioning right now, and I'm digging it. It was the missing piece to this section. I use to create a smoother sound feeding into the Q-tron which is an envelope filter. I'll have clips of this soon, in fact I might need to start a thread because I'm torn between two different ideas for an intro on a song I working on. Sometimes to make things real crazy, I turn on the MoogerFooger to feed into this synth section.
I have the Digitech Bass Synth Wah, which has all these components built into it, and has some great little sounds, but it can be a bit quirky. I generally use only a couple of settings on it. Sometimes I feed the OC-2 into it.
Finally, I have the infamous Boss SYB-5. This pedal is a surprising little box. Many people hate it because of the tracking on it (which is generally bad) but because I always have my clean blended into the sound, I never lose low end or miss a hit because of wonky processor. This synth has some nice little gritty sine wave sounds, as well as a nice hold feature. I use it as a standalone, but recently I've added it to other synths to create a nice gritty flange effect atop my BMS-LPF101 section. I like how it's turned out. Here's a sample of what that sounds like. At 3:02 I kick in the BMS-LPF101 section, and then at 3:19 I add the SYB-5 to the blend.
http://soundcloud.com/downanddirty/come-clean-sunsetsoundsystem-remix
Hope this helps. My name is Maki, and I'm a synthaholic.
