Weight really doesn't determine anything about sound and there is no ideal weight to look for IMHO. I often find that classical guitarists nit pick so many little details like what species of spruce is being used, how is it constructed, what bracing pattern does it have, what country is it made in, what is the head stock veneer, what was the phase of the moon when it was completed, etc. In the end there are too many parts that collectively come together. If we try to single out factors like the weight, species of wood, etc., it can prevent us from really judging the guitar without bias. With that said, I've played mammoth heavy guitars, light guitars, and everything in between, and I've concluded it doesn't really matter. I find that rosewood back and sides, laminated sides, etc. tend to make the guitar heavier, but not worse or less responsive. When an experienced luthier changes the design to make a guitar lighter or heavier, it is usually intentionally and for the purpose of improving the overall sound. Some luthiers make light guitars, some make heavier, but you can have amazing guitars on both ends of the spectrum and the end result depends on a whole host of other factors.
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