Spent a little while with Daniel this AM and got some of The Lady's Harp rails built.
The two rails here are configured differently along a few dimensions. The top one uses the smaller Dayton DAEX58FP transducer, which has a fairly low profile and puts out a maximum of 40W. The lower rail uses the much heftier HDN-8, which is weatherproof and *bumps* a full 100W. Daniel wanted to try both transducers out, and so the tuning blocks (the wood parts, which have piano tuning screws in them) needed to be built at different heights.
Incidentally, these transducers are intended to be mounted to walls, floors or furniture to provide a more tactile audio experience. Imagine 100W of bone-shaking bass when you're watching a movie - I'm not sure it would be enjoyable, but I sure would like to try it out.
I also built the pickup platforms so that they can be gang-mounted (two pickups on one plate) or separated (one pickup per plate). It's possible that the pickups will want to be located at a particular node of the string, and these two configurations will allow all sorts of adjustability.
We should get the whole instrument together next week; expect updates.