Last year I posted here about why its not really possible to get a guitar in tune. I heard from a friend today about tru-temperment fret boards [link dead 2019] which may actually make it possible! Some anecdotal posts in guitar forums indicate that you can play barre chords all the way up the neck with one of these and remain perfectly in tune.

In (somewhat related) readings during lunch today I also found this site [link dead 2019] and I remembered another conversation with some friends recently about the difference between a 440Hz A and 442Hz A. Can you hear the difference between 440Hz and 442Hz?

• http://www.tedrounds.com/mp3_files/A440.mp3 [link dead 2019]
• http://www.tedrounds.com/mp3_files/A442.mp3 [link dead 2019]

Even if you can't discriminate the difference between them when playing them one after another, if you play them simultaneously you'll notice the interference pattern (listen for a waa waa waa sound). This is another way I was taught to tune an electric guitar - while playing a harmonic note on the 12th fret of the lower string, play a harmonic on the 5th fret of the higher string and listen for the interference pattern and tune until the waa waa slows down and disappears. (I'm not at a guitar right now and while my fingers would remember the right frets, my mind doesn't so if thats not right please correct).