James Lister wrote: ↑
Thu Dec 06, 2018 8:26 pm
If you want to build to a particular design that works for you (e.g. Hauser), then you might be better to keep the angle between the strings and the soundboard the same. Rather than slope the whole soundboard downwards towards the neck, you just slope the upper bout down by bending the soundboard at the lower harmonic bar. This keeps the geometry of the lower bout the same.
This is true, however, there is a point that is being missed in this thread. Thomas Humphrey claimed to have developed the sloped top innovation when he introduced his "Millennium" guitar (I've no idea whether he actually did it first nor do I actually care). The purpose was to change the angle of pull on the top moving toward the architecture of a harp. He claimed that this would produce more volume. The resulting elevation of the fret board is nothing more than a by product of the design rather than being the primary feature.
I started making sloped top guitars after our guitar society had booked the Assad brothers for a concert. Both were playing Humphrey Millenniums and said they quite liked them. As part of my research I built a number of guitars with different bracing designs both ways, ie; with and without sloped tops. I cannot say there was a huge difference but most of the folks who regularly try my guitars seemed to feel the sloped topped models produced a little more output.
I don't slope my tops as much as Humphrey did for the simple reason that I like the aesthetics better when the slope is reduced. Another aspect that I rather like is the opportunity to make a fully domed top along with Spanish heel architecture albeit one can do that with traditional designs by placing an angled shim from neck wood beneath the fret board where it joins to the upper bout to fill the resulting gap.