The sustain is very long, though 645mm scale.
The guitar is suffering from backbow.
To make it less of a buzzing problem, I took 1.5 hours to help alleviate the buzz when playing high D with 6th string fretted (the problem that I have since diagnosed as uneven frets). But now when second string G on 8th, the 6th string buzz when fretted!!!
The frets were levelled and glued in 3 fret ends that were loosed (6th, 7th and 11th). So I advised client to use higher tension strings - I gave him a pack of D'addario EJ46.
I wish I had taken photos.
