I have built 3 rosewood body 12-fret 00 guitars (like a Martin 00-21) in the last few years. The first one had an Engelmann top, the second had a Sitka top, and the third had an Adirondack top. The thickness of each of the tops was (very close) to 0.100", and all had the same bracing pattern. The Engelmann top guitar sounded terrific, but the Sitka and Adirondack topped guitars sounded stiff (I think boxy might be the right description of the tone) with less bass (even for a 00). The 2nd and 3rd guitars opened up some over time, but not as much as the Engelmann top guitar. Because of similarities in construction, I am led to suspect that a large factor in the difference in tone might be in the stiffness of the tops made from different types of spruce: (1) Does that sound plausible to you? (2) Should I be thinning the tops on stiffer spruces another 0.010" or so? (3) Is it plausible that this is just a difference in the time for the spruce varieties to open up, (4) Are there other things that you imaging might be causing the differences in tone. (5) Other advice?
Thanks in advance for sharing your thoughts and knowledge,