This is a bit of internet seredipidy .Not strictly guitars but I read that 2.9khz is the very best frequency to tune your violin bridge. (about two and a half octaves above middle C.) This triggered an article that said Snowy Tree Cricket chirps are exactly 2.9 khz.
When I test a bridge now,I drop the bridge on the sole of my steel plane.The rattle "note" as it lands can be compared to the chirp recording (on the insect site).
The affect on the tone is really amazing.Real quality sounds.If you go past the 2.9 khz there is a sudden drop in sound quality. Frequency rises as you remove wood (from the top 1 1/2 cms.)
Is there an insect for guitars? If you have ever made a violin ,go back and use this .It is a lot of fun.Very quick and reliable.