If any thread here on the db side needs killin', this be the one. And since I'm probably leading the league in threadkill posts on the db side of TB, who better to do the dirty work?
Disclaimer-- Ian, there is no "expertise," assembled or otherwise, to be found in this post. Just to get that out of the way.
Bold statement-- If a feller wanted to make his upright bass sound like a cheap bass guitar, well shucks all he oughta do is get hisself wunna them compressor gizmos, crank it up, and squash every last little bit of life right out of his signal boy howdy amen. 'Course, you don't gotta squeeze
that hard, but every little bit of compression you use gives you that much less upright and that much more bass guitar.
Personal opinion-- In general, compression is overrated, overused, and over-misunderstood. With particular respect to double bass, it should be avoided when possible and used carefully and expertly only if necessary to fix a particular, specifc problem.
Personal experience-- That said, I have yes indeedy used a compressor, on stage, to address a particular specific problem with a certain pickup that I was using. The problem was a huge thump in the attack of certain notes and much of the energy was in the <80Hz range. I used a FEA Dual Band to act as a hard limiter, set so that it would only limit the problem frequencies just enough and leave everything else untouched. It worked pretty well, clamping down on the offenders without significantly altering the overall tone. I no longer use that pickup much and therefore the FEA, beautiful and capable though it is, sits mostly idle.
Prediction-- I am not a good bassist, but I guess that most of the name brand players I've heard would work to "even out the amplitude"
digitally, by which I mean, with their fingers.
Having said all that: if you are undaunted and still want to experiment with compressors, I don't think you can do better than FEA. Different, yes, but not better. And no, you can't have mine
-bob