Comments on: Bowed Psaltery Woods: Impedance vs. Dampening http://blog.phantasypsalteries.com/bowed-psaltery-woods-impedance-vs-dampening/ Eric Meier's Bowed Psaltery Blog Mon, 15 Feb 2010 22:04:31 -0800 http://wordpress.org/?v=2.9.1 hourly 1 By: Eric http://blog.phantasypsalteries.com/bowed-psaltery-woods-impedance-vs-dampening/comment-page-1/#comment-1143 Eric Mon, 15 Feb 2010 22:04:31 +0000 http://blog.phantasypsalteries.com/bowed-psaltery-woods-impedance-vs-dampening/#comment-1143 Antonio, those are some good thoughts to add to the discussion. My feelings on bridges, both in materials and placement, are mixed. On the one hand, you consider the acoustic qualities, and want to make it light, with as little impedance as possible. Yet on the other hand, there is an amazing amount of pressure being exerted upon the soundboard by all of the strings---roughly 4 or 5 times more strings than on a steel-string guitar---with the heaviest stress point being the area under the bridge. In the end, I opt for the safer route, and try to use stiffer woods for the bridge, and keep it very close to the pinblock for reinforcement. I believe that this is the best choice for the long-term durability of the instrument. I haven't really experimented with moving the bridge any closer to the soundhole. Antonio, those are some good thoughts to add to the discussion.

My feelings on bridges, both in materials and placement, are mixed. On the one hand, you consider the acoustic qualities, and want to make it light, with as little impedance as possible. Yet on the other hand, there is an amazing amount of pressure being exerted upon the soundboard by all of the strings—roughly 4 or 5 times more strings than on a steel-string guitar—with the heaviest stress point being the area under the bridge.

In the end, I opt for the safer route, and try to use stiffer woods for the bridge, and keep it very close to the pinblock for reinforcement. I believe that this is the best choice for the long-term durability of the instrument. I haven’t really experimented with moving the bridge any closer to the soundhole.

]]> By: Antonio http://blog.phantasypsalteries.com/bowed-psaltery-woods-impedance-vs-dampening/comment-page-1/#comment-1142 Antonio Sun, 14 Feb 2010 18:49:56 +0000 http://blog.phantasypsalteries.com/bowed-psaltery-woods-impedance-vs-dampening/#comment-1142 I ran into psimple psaltery website while looking for "helmholtz resonance" on Google. During the restoration process of an old italian mandolin i was calculating the difference in Helmholtz frequency due to a few mm larger soundhole (result: less than a quarter of tone). I didn't learn much more about Helmholtz resonance, but now I'm searching the wood to build a bowed psaltery. My two cents thinking about impedance: the soundboard has to vibrate, in order to move big amounts of air, the body has not to vibrate. The body vibrates, anyhow, but in my opinion it affects some internal resonances of the instruments, not the 'basic' way the sound is produced. A bigger problem is the coupling of impedances between the strings and the soundboard, that is: the bridge. I think it has to be light and stiff (maybe ebony and bone, or a 'psimple' aluminum bar with triangular section). How the sound changes when positioning the bridge 1 or 2 cm nearer the sound hole? (a longer psaltery) Thanks in advance Antonio I ran into psimple psaltery website while looking for “helmholtz resonance” on Google. During the restoration process of an old italian mandolin i was calculating the difference in Helmholtz frequency due to a few mm larger soundhole (result: less than a quarter of tone).
I didn’t learn much more about Helmholtz resonance, but now I’m searching the wood to build a bowed psaltery.
My two cents thinking about impedance: the soundboard has to vibrate, in order to move big amounts of air, the body has not to vibrate. The body vibrates, anyhow, but in my opinion it affects some internal resonances of the instruments, not the ‘basic’ way the sound is produced.
A bigger problem is the coupling of impedances between the strings and the soundboard, that is: the bridge. I think it has to be light and stiff (maybe ebony and bone, or a ‘psimple’ aluminum bar with triangular section).
How the sound changes when positioning the bridge 1 or 2 cm nearer the sound hole? (a longer psaltery)
Thanks in advance
Antonio

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