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Some Pipe and Register Measurements

Posted under Musical Technology at .
Tags:organ, prime, typography, history
This is an update to Notes from an Exploration of a Vermona Synthesizer.

(Actually an update to a tangential note.)

I mused:

Are feet and Prime an English-language convention? Since this convention stems from pipe organs, were pipe organs all over Europe described in feet, in the past? . . . Have there ever been organs (or synths) described in cm? Or, were the Prime (′″) marks used with other pre-metric measurements?

From a survey of the web, it seems that different languages do use versions of the foot measurement to describe organ registers, but the Prime mark was not always used. e.g.:

These actual measurements were not identical, even within language zones, which complicates matters for tuning . . . though apparently tuning just was complicated, back when pipe organs were bleeding-edge tech.

Meanwhile, this page states: The foot used in organ building is 32,43 centimeters long. It’s not clear whether this is a traditional or modern unit, (though it’s almost but not quite the French pied du roi). However, a C of 1311mm wavelength translates as 4·043 of these feet, or about 4′½″ assuming 12 inches to the foot. Which is probably within the range of pitch variation to be expected from other aspects of pipe construction and playing conditions. (And it makes more sense than the English foot, which at 304·8mm is nearer a C♯.)

In any case, I have found no reference to a metric organ register. Opportunity for someone. (happy emoticon) Or you could just use frequency.

To clarify that: Over and above language questions, it strikes me as odd that synths generally use pipe-organ register labels for octave transposition controls. They derive not from actual wavelengths but from reference lengths for groups of pipes, and as it turns out, these lengths are expressed in a specialist measurement unit. So in a sense it is odd that synths have inherited this terminology — although as pipe organs were the (freaking-awesome high-tech) synthesisers of the latter Middle Ages to 20th Century, it may not be inappropriate. (Right, they still are freaking awesome high tech, just a different kind of high, and rather out of most people’s reach, which is another kind of high.)

You could equally well label the controls according to metric wavelengths — but the wavelengths present in the circuits are not those you want the speakers to produce. Or metric pipe lengths — 1037/519/259/130/65cm rather than 32′/16′/8′/4′/2′.

Or you could use frequency, which is the consistent phenomenon under control. But that would presumably mean labels like 16–523Hz/33–1047Hz/65–2093Hz/131–4186Hz/262–8372Hz, which is why we don’t do it.

Or, as on some synths, e.g. Rolands, you could just have a transpose up/down switch and don’t sweat the detail. Assuming you’re building a transposing rather than a multi-octave and potentially additive synth like the Vermona.

Oh, and, yes, the Prime marks were used in the written forms of many European languages at least by the end of the Nineteenth Century to represent minutes and seconds of arc, or of time, and some other units; but I haven’t found a complete history of their use.


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