I've had this link for quite a while, and about once a month take a look at it. It's very educational and can provide some insight for fine tuning your keyboards and sound systems. Take a look at http://www.independentrecording.net/irn/resources/freqchart/main_display.htm

Almost forgot the second link: http://www.recordingwebsite.com/articles/eqfreq.php

Enjoy,

Gary

[This message has been edited by travlin'easy (edited 08-16-2010).]