Hi, I was browsing through a guitar shop the other day and I noticed something. I noticed that solid top guitars seem to have varying grades of wood. Example that i saw is Sitka spruce AA or Sitka spruce A. How do people classify their woods?
I couldn't really hear any differences between the guitar made from grade AA or simply grade A wood. I haven't been playing for long, so it could simply be just be that my ears isn't sensitive enough. But is there anyone here who feels that the grade of the wood does make a large impact on the tonal qualities of the guitar?
From http://www.instrumentmakers.net/LLcom/tonewoods/tonewoods.html

" The common grading scale for tonewoods is A, AA, AAA, and AAAA or master grade.
This grading scale is used by most retail sellers of tonewoods and is very subjective. Although many of the visual attributes of a piece of tonewood are indicators of structural strength and good taptone.

Grade A is clear of knots, swirls, and holes and has fairly straight grain. It may have uneven color, streaks, and wide apart/uneven grain lines, also called compression. It will probably not be perfectly quartersawn or the piece will be perfectly quartered only in part of its width. The piece of wood will also probably have runout. There will be little cross-grain figure.

Grade AAA has even overall color, even and close grain lines, perfectly quartersawn along the whole width of the board, with minimal runout. Grain lines will probably be closer than 12 lines per inch. Cross-grain figure, also called silking or bearclaw will be visible.

Grade AA is somewhere between A and AAA grade.

Grade AAAA or Master grade has no color variation and very pronounced cross-grain figuring in addition to being perfectly quartered with minimal runout and close and even grain lines."
I should probably clarify that there are more specific requirements for certain types of woods. For example, some woods like quilted maple are more highly prized for the amount of figuring that is displayed, while for exotic woods such as cocobolo or striped ebony, extreme color variation is a desired quality rather than a flaw.

You can easily find the specifics for specific types of wood if you google around a bit. Check out this R. Taylor (or any R. Taylor) for an example of mastergrade wood - http://www.rtaylorguitars.com/Woods-Backs-Sides-08.aspx - you've never seen mahoghany like this before
That was informative. Thanks. And I must say that piece of wood does look amazing. Never seen anything like that before.