I’ve made a surprising discovery about the A-string on my guitar. Other musicians have probably noticed that the A-string is the first to fall out of standard tuning.(A=440 hertz) But, when I play the following video in resonance with ancient, solfeggio(A=432 Hertz), this guitar string is always in-tune. I’d appreciate anyone willing to verify this with their own instrument. Play video and pluck the A-string to see whether the two are not already in-sync.