250 Hz : The Buzz Zone. I'm not talking about the buzz you get with bad ear plugs, but the type of buzz that makes Jaco's bass roar like a tiger and the one you get when you play really near from the bridge, plucking hard with your fingers. If you like that feeling, here is the range of frequencies it comes from : about 150 to 400 Hz.

Use this frequency range if you play 60s pop songs with a suede pick like Carol Kayes, 70s rock like Jack Bruce in Cream, Roger Glover with Deep Purple or Sting with Police, or if you're just looking for big ol' round and bright bass sound. It's also the frequency to boost if you plan to slap, get a guitar-like sound, or if you like "modern" sounding bass EQing. If you need to "dry" your sound, play Death Metal with a pick, or your final mix sounds "enclosed", lower this frequency.

Tip : If you can't hear yourself well in a rock band, or in a reggae band with leads, lower your general volume a little and boost this frequency a lot, (around +10 dB). It will help you cut through much better.