Harp Soundboard Reinforcement Bars

Since my harp soundboard is made of solid spruce, it will require some reinforcing bars. I have added two, one on top and one on the underside of the harp. The underside bar of maple, and is tapered in width as well as in thickness, being the thickest and widest at the bottom. The top is an exact match, but is made of walnut for cosmetic purposes. One of my innovations (this is not customary harp building) was to attach two spruce ribs to the top reinforcing bar. This is a take off from my piano soundboard building. Note that on a piano the ribs are on the under side, while on the harp, I placed them on the top side. This is because on a piano the pressure of the string are pushing down, but on the harp, the pressure of the strings are pulling up. The purpose of the ribs is to produce an internal stress on the soundboard that in turn produces a slight crown. The theory is that this enhances the sound produced by the board. It works in pianos. We'll see if it works in harps. The first photo is gluing the ribs to the top reinforcing bar. The second is gluing the reinforcement bars to the soundboard in my piano soundboard press. Note that the soundboard was dried to 5.5% EMC before the reinforcement bars were glued. This is an important matter that is often overlooked, as the soundboard does change dimensionally as the wood dries (more piano influence on my harp).