String height above bridge: How tall is too tall?

[Talldad]

Originally Posted by Alan Carruth

Talldad wrote:


At any rate, as I pointed out in a previous post, the tension change signal is not what makes most of the sound: that comes from vertical motion of the string relative to the soundboard which pulls the top up and down. This moves the top like a loudspeaker, which is 'way more effective at making sound than rocking the bridge.

I could say a lot more, but since I've already said it in this thread, and numerous other times in various groups, I don't want to repeat myself now. This all comes from experiments I've done, and fits with the well known physics of strings and guitar tops. Look up those other posts, read them through carefully, and get back to me if there's still something that needs explaining.

Absolutely agree with you alan. In the context of this thread the Saddle Height is most likely to affect the rocking forward backwards motion of the bridge (torsional). This in turn will affect the Long Dipole response, commonly thought of as the waves motion of the soundboard that projects the guitars sounds into a room.

Other motions will come into play and, as you say, have a greater effect on the tone of the sound.

[lar]

Very interesting information would be gathered from mounting a 3-axis accelerometer placed on the bridge and (separately) the saddle. Icing on the cake would be some accels on the soundboard too. I'm not sure what the full scale range should be, but there are triple-axis accels available that weigh a few grams, and are 3-4mm (.11") square. I'm sure someone has done this testing before (published papers, etc...).

[Alan Carruth]

I did some work with a small accelerometer at one point. Basically, it showed that a given force perpendicular to the soundboard gives you the most motion. Force parallel to the string axis (such as the 'tension change' and 'zip' signals) produces much less motion, and only becomes effective around the long dipole pitch. Force across the bridge does't do much.

A lot of this information is on my web site in a .pdf entitled 'String Theory' ( I couldn't resist). It's on the 'Acoustics' page. That was work I did some time ago, and I'm working on refining the data on that as I can.