Francesco Tribioli wrote: > When I went to collect the new marvelous 6c that Martin Shepherd > built me, he showed me that the two main chains under a Renaissance top > where not parallel but slightly angled. I think that this was done to > counterbalance the effect of reinforcement of the oscillating modes which > have the nodes where the bars are, making different part of the top > responding better to different frequencies. > > > Dear All,
Francesco is referring to an old top I showed him which had the bars not at right angles to the centreline of the soundboard but angled slightly this way and that. I said that this was because I had seen this kind of thing on old lutes and wondered if there was a reason for it, other than mere carelessness on the part of the old makers. It is, after all, very easy to glue the bars on perfectly straight "by eye", so we can't explain it simply by saying that they didn't mark it out. I wondered vaguely about the "oscillating nodes" idea, but I'm not a physicist and I can't really judge the likelihood of that hypothesis, though I am sympathetic to the idea that a degree of randomness might be a useful characteristic in terms of discouraging the dominance of particular frequencies. On the other hand it could just be another example of the old makers working very quickly and even sloppily, taking care only for the important aspects of the work and not being (as we tend to be) obsessed by right angles and straight lines. I think of the 1592 Venere lute in Bologna - a very beautiful, decorated instrument where the pegbox is glued on at the crazy angle (i.e., the centre line of the pegbox is nowhere near parallel with the centre line of the neck). Some things just don't matter. Best wishes, Martin To get on or off this list see list information at http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html
