Double top guitars.

That is an interesting video, since I don't know anything about these kinds of things. My William Kelday 000 12 fret has double sides. Since he is in Scotland, I am not in a position to sit down with him and have him describe what that really means. I suppose I could email him. Anyway, what I have read is that double sides are similar to laminated sides except that both pieces are of the same kind of wood, with the grain going in the same direction. Also from what I read, the purpose of double sides is to add stiffness and strength so that the top can be thinner and more resonant.

My Kelday is often described as having a "chimey" (not the bright sound often associated with Taylor guitars) sound that is really good for open tunings, which is what Kelday says is his goal on his site. Some guitars tend to sound a bit muddy when the strings are tuned way down for various open and alternate tunings. Mine retains its clarity and resonance, and is (in my opinion) the clear best of my guitars for open/alternate tuning.

Another approach to achieving this is the fan fret guitar. I have tried some of those, and I just can't seem to get comfortable with them, so my Kelday is the way to go for me for open/alternate tunings.

From what the video on double tops seems to describe, the double top is more of a sandwich with the two pieces of wood and another material in between to provide space between the two pieces of wood, resulting in greater resonance, clarity, etc. The guitar in the video sounds really good to me, so maybe I should be on the lookout for a double top guitar someday, if somebody is willing to "gift" me one as people seem to say these days.

How would a guitar with double sides AND double top sound different from a similar build with one or the other, or none?

Tony