So my Sony STR-DB930's equalizer for the front bass goes from 100Hz to 1KHz. Now, is this setting a MIN, MAX, or centering Frequency? I am feeding it a constant test tone signal (say 60 Hz or 150 Hz) and it doesn't seem to change no matter if I move the EQ setting from 100 Hz to 1KHz. My speakers are rated to 42 Hz +- 3 Hz, but they are barely breathing at 49 Hz (I can kinda hear them still at ~47). Changing the EQ settings seems to have zero effect on the sounds coming out of my speakers. Thoughts?