EQ help: how best to adjust the 5 bands of the EQ's Custom setting (and to understand them)?

One thing I’ve found with the settings that cllipman proposed is that my left earbud has a noticeable amount of buzzing when playing many of the songs I’ve had.  At first I noticed it with the song “Everything in its Right Place” by Radiohead.  The buzzing also occurs with my $30 set of Sony headphones and I’m wondering if it’s the player, the headphones, or just the settings. 

It seems weird that it’s only in one ear and that on both headphones it’s the same ear.