The Profiler is able to manage, preamplify and process any kind of audio signal. Results may vary according to the settings you apply, the quality of the fed signal and your needs.
NOTE: You can also select Return Input as your Input Source in the Input menu. Then you don't have occupy one of your Stomps/Effects slots with an FX Loop to get an input signal. Just remember to only use the Mono Loop effect if you need to place external effects in the KPA's effects loop, as a stereo loop requires the Return Input.
For playing acoustic guitar with the Profiler, there are several profiles available. Just adjust the EQ, chorus, delay or reverb.
We can even bypass the amp and the cab, just keep EQ and effects and the volume. It works too... Don’t be shy about selecting a clean rig and tweaking, I have had some very pleasing results through an acoustic and under saddle pick up. That's what I do with my nylon string acoustic - and it works wonderfully. Very natural.
Also, if you use a steel string acoustic with the Fishman profile, fool around a bit with the amp compressor parameter. For me it yielded good results for some mixes where I needed a sort of more dense acoustic sound.
New along with FW 1.6: Rig Pack 04 does include 5 rigs tailored for acoustic guitars.
On the Rig Exchange, look for:
- "DP Piezo", it’s a set of 3 rigs by guitarnet70. They where made for use with piezo and active preamp (Ovation).
- “California Blonde”. Just tweak the EQ for your needs.
- "Jazz clean sm57". I suggest you to try it without the cab.
- The Fishman profiles. If you use a steel string acoustic, fool around a bit with the amp compressor parameter. For me it yielded good results for some mixes where I needed a sort of more dense acoustic sound.
- "Acoustic Dream" preset by Flitzefinger. It is a beautiful acoustic/piezo simulation. (well, at least with my single coils) But with some EQ, I'm sure it will be great even for humbuckers. 
- “Acoustic A/B/C/D/E” profiles by M. Franzkowiak are included in Rig Pack 4.
Mr. Kemper has suggested allowing the Stomps slots A and B to be arranged in a parallel configuration for a future firmware release (2.2.2?), specifically with the idea of bass tones. This would allow users to mix a distorted and clean bass tone in parallel, going beyond the capabilities of the Direct Mix parameter.
Includes both stock and user-created
- Ampeg B15
- Ampeg SVT450
- Ampeg SVT- IIP bass preamp
- Dakota (“Mr Dakota”)
- Eden Traveller
- Eden WDTI (thread)
- Gallien & Krueger 800RB
- Genz-Benz (thread)
- Selmer Twin B30
- SVX Pop Bass (Amplitube 3 Free using the SVX bundle (Virtual Ampeg Bass Amps))
- Waves CLA Bass plugin (“CLA Bass Start Me Up”)
Also, consider all the Fender Bassman amps on the Rig Exchange.
Generally, you can always search the Rig Exchange for “bass”.
Commercial bass profiles
Check Soundside’s SansAmp (all the bass presets have been profiled) and "Mark Bass F1 Bass Guitar Amp" (37 profiles for all kinds of sounds) profiles.
I just got the best freaking bass tone I've ever gotten with a free profile from The Amp Factory. An Ampeg BA115. It sounds better than going direct box through my 1073 and Retro Sta-Level. Unbelievable. 
For metal bass tones, check out Sonic Underground's profiles.
If you are looking for profiles to record or for practice, don't overlook amps like AC 30's, which sound great for bass, when recording. There's a 100 watt Marshall bass amp in the Rig Exchange too. I just wish there was one with the matching bass cab. Quite a few Fender Bassman profiles to choose from too… not to mention all the great Ampegs and usual bass amps. Andy has some free ones at The Amp Factory. I have used them to record with and they work for me.