frequency table – A PHP script allowing the reference pitch of A4 to be altered from 440 Hz. PySynth – A simple Python-based software synthesizer that prints the key frequencies table and then creates a few demo songs based on that table. "Keyboard and frequencies", SengpielAudio.com. Notefreqs – A complete table of note frequencies and ratios for midi, piano, guitar, bass, and violin. Includes fret measurements (in cm and inches) for building instruments. Piano Musical tuning