Here's a link to an excellent chart which shows the hz (cycle per second) for all the notes (pitches) of a piano. You will notice that 'hz' doubles when you go up an octave and is halved an octave lower. This should provide an easy way to determine what range of notes you are actually boosting/lowering when you select a given frequency on the PSR2000's Equalizer. In fact, this chart should be useful for all synth/arranger keyboard owners: http://www.pianoworld.com/pitch.htm