Customer wanted action lowered on a Martin D-35. Guitar had plenty of saddle to adjust. I checked the relief was between .010 and .016. Nut is in good shape. The action before was approximately 3mm on bass, 2mm on treble at 12th fret, but customer wanted a little lower. After lowering to 2.7mm on bass and 1.5 on treble, guitar played very well except A string at 5th and 7th fret. I checked frets for level and found they were good, so I just did a light dressing to make sure. At this point I felt it was too low, so I remade the saddle back to original. I'm still getting a little buzz at the 5th and 7th frets on the A string. I have read everything on your site as far as buzzing and still can't figure it out. Help!
The only thing I feel could be done is to remove frets, relevel fingerboard, and replace with new frets. I feel that neck angle to the bridge is in good shape. I ran a straight edge to the bridge and just about touched the saddle. The measurement at the bridge from top of guitar to low E string is a half inch. I feel maybe the fingerboard is just a little low at A string between 5th and 7th frets. I don't know what else to do.