I am not sure if the following is true but, since I use passive basses most of the time, my instruments dont have as much headroom as say basses with 18V/27V preamps. I'm assuming that I'm less prone to volume spikes since i play with a hard and fairly consistent attack. Again, it seems easier for me since I use passive basses with lower ouputs and lesser headroom. Is this true at all?
Not so much, actually. It's all in how you set your levels (including the "level" of your finger/pick attack). You have found levels that work for you and your specific rig; other rigs/basses just require different level settings for the exact same results. "Output level" and "dynamics" are not at all the same thing.
My observation, in experimenting with so many compressors, is that people who complain that compressors kill their tone, cut them out of the mix, screw with their dynamics, etc. either didn't know how to set them up properly, or were stuck using a lame compressor. There really are a lot of comps out there that suck; there are also plenty that require you spend a fair amount of time learning how to use them properly, and understand their specific strengths and weaknesses.
For example, all the time we see posts like "I have a 100W Behringer amp, and I crank it all the way up but it still doesn't sound like JPJ or Geddy, and I can't hear myself over the guitarist... what kind of distortion pedal should I buy?" The real answer is they need to learn a lot more about how amplifiers work, and get the right amp for the job. It's exactly the same with compression- not only do you have to start off with the right tool for the job (i.e. a comp that is suitable for your playing style, and no they are not all the same); you also have to understand what each of the features does, and how it affects your tone, dynamics, and place in the mix.
All of this is
by no means to say that everyone should like compressors and use them. But I do feel certain that the people who say "compressors kill my sound" need to (a) try a different comp, and (b) spend some time learning how to get what they want from it. Of course, a lot of people (quite reasonably) don't have the patience for that, or just want to plug and play, and that's fine for them, but it's not a problem with the compressor.
