The serial number of an acoustic is located on the label inside the sound hole of the guitar. All acoustic serial numbers begin with the letter A, and are followed by the two digit year prefix. The remaining digits indicate the sequential number of acoustics built to date.

What sounds do a guitar make?

Sound is produced by striking the strings and making them vibrate. The pitch of the vibrating strings depends partly on the mass, tension, and length of the strings. On steel-string guitars, the lower strings are thicker. Tuning the strings changes the tension; the tighter the string, the higher the pitch.