Hi Danny, Horace, and all, I think this is a very good example of modifying the natural harmonic frequency of board in that area to more nearly match the frequency ranges it's supposed to handle. The bass strings are weighted by heavy wrapping for the same reason (roughly). It's tough to make a tweeter woof. Lighter, thinner board and more and thinner ribs might very well do the same for the treble (or, might not!). It's also tough to make a woofer tweet. Ron At 10:42 AM 12/10/97 -0600, you wrote: >Horace Greeley wrote: > >> I'm not sure about 6 or 7 seconds, maybe Del could shed some light, but >> certainly some >> improvement might be possible. > >This demonstration was on a 30 year old console that had some real unpleasant >screeching overtones about the 7th and 8th partials. My guess was that there >were some inherant impedance problems that allowed those partials to continue >to sing as the lower partials decayed too quickly. I suspect that the lead >weights damped the objectionable partials while allowing the lower partials to >resonate more naturally. I guess there could have been some comb filtering >within the board that caused the more desirable partials to be cancelled. > >Again, this was mere speculation - I'm not a physicist. > >Danny > >> >> >> Horace >> >> At 11:52 PM 12/8/97 -0600, you wrote: >> >Susan, >> > >> >Wouldn't this sort of work as the inverse of weighting soundboards? I've >> never >> >heard a plausable explanation of why the lead weights work, but I've heard >> 1 or 2 >> >well placed weights add 6 or 7 seconds to bass sustain while damping out >> >unpleasant overtones.. >> > >> >Danny Moore >> >Houston Chapter >> > >> >Susan Kline wrote: >> > >> >> use a router and/or plane to thin one side, with the strings still on >> >> and at pitch. Possibly they could add mass to the other side as well, by >> >> gluing or clamping something to those ribs.. >> > >> > >> > >> Horace Greeley >> >> Systems Analyst/Engineer >> Controller's Office >> Stanford University >> >> email: hgreeley@leland.stanford.edu >> voice mail: 650.725.9062 >> fax: 650.725.8014 > > > Ron Nossaman
This PTG archive page provided courtesy of Moy Piano Service, LLC