Official Luthiers Forum!

Of course practical demands in application drive the designs. Regarding historical perspective of pitch standards and tunings though, it is equally important to remember string materials/properties/gauges have fluctuated at least as much. And then of course the strings and tunings are also adjusted to fit within boundaries dictated by ergonomics, so it's a dance between several malleable factors.

In estimating original intent though, when it comes to deciding an a starting number from which to calculate fret spacings, humans gravitate toward reasonable round numbers. If a scale seems entirely arbitrary you can typically find a reasonable whole number or fraction at its source.

In production instruments if a number seems completely random on the surface, there is likely to be a reasonably round number at its origin. Could be converted from different measurement units, or calculated to a different formula than we assume. Could be tooling errors, or perhaps something like having started with a round number for a different scale and added an additional or subtracted a fret at the end to lengthen or shorten the scale with existing tooling. Go back far enough in instrument design and it could be a result drawn from a compass or trammel, or any number of other origins. Most often though, there are reasonably rational or round starting points which can be found if you look close enough.

This is of course little more than academic historical research, which I personally find to be an irresistible riddle.

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Eschew obfuscation, espouse elucidation.

One thing I didn't mention before is that in the 1960s Martin used to recommend certain string guages and types for the various models. These were included on the specifications page in the catalogs of the period.
This was back before scalloped bracing was reintroduced so it wasn't driven by that, though indeed some of the guitars were braced lighter than others.
I heard that the fret placements were modified to work with whatever strings (Medium Bronze, Silk and Steel, Nylon etc.) were specified.
I've never checked any of my guitars from that time to see if there are indeed variances in the spacings.

Thank goodness Jimmy Carter put a stop to that metric thing in the US back in the 70's.
At the time, I was working at a place that used military time keeping. i had enough trouble telling what time it really was.
i have been using mils for 30 years in my line of work. I'm used to it and prefer it.

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Lucky! Our Prime Minister at the time dragged us into the metric world with the thinking that the USA would have to follow suit. Ha! So now our biggest trading partner uses imperial measure, and we have to label everything in both measures, and half of the population still thinks in imperial. That Prime Minister's supply school teacher son is now the leader of the opposition, and thinks that world peace can be achieved if we all hold hands and sing Kumbaya.
Sorry about the political rant Lance, but Canada probably doesn't count, does it?

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

Indeed!

The class I was in at school was the first year that the science subjects were taught in SI units. That was "pure" SI units before political correctness (which hadn't even been coined as a term, at that stage) butchered it around, mainly perpetrated by politicians who have no idea (I'd usually put it a little stronger than that...). Prior to that year, whilst I was interested in science, I found it incomprehensible because of the mish-mash of units, conversion factors (seemly introduced at random) and weird names (poundals, slugs, rods, poles, perches, chains, etc.) which meant I could never get a calculation right.

After the introduction of SI, everything made sense. In my time I've worked across a lot of branches of science; applied mathematics, physics, chemistry, engineering (various branches), acoustics, etc. and SI units are transferable and cohesive right across the spectrum.

If it hadn't been for SI units, I'd probably be a medic rather than an engineer. Wouldn't that have saved a bunch of you guys a lot of trouble?

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

We still have the weakness of base 10. Even just two more digits between 1 and "10", and the world would seem so much more rational.

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Eschew obfuscation, espouse elucidation.

We cannot even agree on how to spell liter and meter. I still don't know why school kids have to learn the Roman numeral system. Nothing beats having to add and subtract to figure out what the heck number MMLXVI is.

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If they don't learn roman numerals, kids will never know in what year their' favourite movie was made in, and they won't know what chapter they are reading in a Shakespeare play. I wonder if kids today know what "Four score and seven years ago..." is?

Alex

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"Indecision is the key to flexibility" .... Bumper sticker