i have zero experience with compressors, but i have read all the threads, but my situation is alittle different. i'm an upright player and i also play electric upright. i have some dead spots on both basses that i want to even out. mostly in the upper register. my primary concern is bringing out sustain and equilizing the volume over the entire fingerboard. is there a compressor that is more suited to this than others? also, how important is it to have a know to slect the ratio on the compressor? one more thing. i did try compression once on the upright, and it caused some feedback. i'm guessing because i didnt have it optimally set. are there compressors that would be more advantageous to the upright that are different than the ones that would be better for my solid body upright? thanks in advance!