I have no idea Rod, it was Dominic who posted about the double backed archtop Yeah I must admit I would be interested in hearing/seeing one but as I say, most top archtop players either play them on their knee or slanted away from themselves so would seem like alot of effort to go to for minimal gains (if any) on an archtop.rocket wrote:Very interesting, Nick i've seen posts on double backed flat tops but not on archtops. Is the inner back on the archtops arched or flat?
Cheers,,, Rod
Speculate away Puff, that's why these discussions are always good & I'm always more than willing to review my ideas on things, I'm far from having all the clues on this luthiery caper! I've never been one for working things out on a board or having screeds of mathematical formula, I'm very much a design from idea, build the first one & tinker with it type of person.Puff wrote:Nick if I may speculate.
Without taking the structural functions of top and back and sides out of play, inner backs will act very much the same as an undamped single back. The top will still be under compression between bridge and neck. Under tension between tail block and bridge. The effective back will still be under tension between neck block and tail. Albeit to a lesser degree.
Having learnt that reasonable 'wood' can be made from inexpensive veneers and fibre and glue, experimentation does not have to be toxic or expensive - but it is still time consuming.
Oooops - probably just set myself up for incoming
You are correct that it is essentially the same as having a responsive single back & that is possible if played in the sitting position but hang a strap on the guitar & stand up & your responsive back is no longer such, it becomes a reflective back as the player's body damps out the back's movement. It would be possible to turn it back into a responsive back by merely tilting it away from you as you play (ala Archtop players & BB King ) but then makes it uncomfortable to wear as a corner digs into your ribs & uncomfortable to play as your fretting hand's wrist has to bend back further still. I also wanted to remove any bracing from the 'active' surface of the back just incase traditionally high bracing causes any funky wave paths inside the box, I don't know if any do occur (like I say, I'm more of a suck it & see kind of guy), but anything put in the way of a soundwave must have some effect on it, if I could remove a few of those interferences then it must be a more efficient instrument in some respects.