Some Pipe and Register Measurements

(Anorak Adventures in Synthland 5)

(This is an update to a tangential note in Notes from an Exploration of a Vermona Synthesizer.)

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.:

  • Fuß in German.  Prime U+2032 ⟨′⟩ is used on this page.  But in this example from 1750, a period (or something similar) follows the register number.  According to the present state of de.wikipedia the Prime mark is also used in German for a minute of arc – though Iʼm not clear whether this is a traditional or modern usage – and to signify either the English or French foot unit.  What, not FußThe page on Fuß is rather clearer, and even has a section on feet in organ building, though it doesnʼt address the question of the origin of the use of Prime.  Still, this all confirms that, in this respect, the Vermona Synthʼs labelling is in line with modern German convention, rather than aimed at a hypothetical Anglophone market, which is what I was wondering.
  • Pied in French.  (Straight single quote U+27 ⟨'⟩ used on this page, though other sites use Prime.)  Here ‘fond’ also appears to be used rather than pied – or does that translate to ‘register’?  But I havenʼt found a close-up image of a pre-metric French-made stop or other example of traditional abbreviation.  Nevertheless, the Prime symbols are used in French convention for minutes and seconds of arc.  This could be taken to imply that usage for other unit systems was conventional once.  There is a brief mention in the pied’ article on fr.wikipedia of a ‘pied acoustique’ of 324mm used in organ building.
  • Pied in Italian.  (U+27 used on this page.)  No pre-metric Italian stop images found either.
  • Voet in Dutch (abbreviated as Vt. or V). has a superb collection of images of organs and their stops, showing Vt. as an abbreviation as early as 1521.  It looks as though pipe organs do not use Prime as an abbreviation in the Netherlands.
  • Stopa in Polish.  Stopa is the the Polish word for foot, curiously reminiscent of the English term for the control knob for a register.  (Coincidence?  Well, stop in English is related to stomp or stub ... so not in all ways.  But I donʼt think this is where organ stops got their name.)  The pl.wikipedia page uses U+27 as an abbreviation.
  • Since the question about feet is also implied on the Polivoks, letʼs see...  The pre-metric Russian units apparently were standardised against the English Foot in around 1700, and one of them was in fact the foot (фут, though the Russian word for foot is под).  ru.wikipediaʼs page on organs seems to confirm that a foot-related measure, футовые, is also used in Russian for the registers and perhaps for pipes.  There are no Primes on this page (though there is one lone U+27 which might just be an accidental remnant of a copy-paste).  So what to make of that?  Not sure.  If the prime marks on actual synths are pronounced фут it would at least be more contextually consistent than in German, perhaps.

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.”  Itʼs not clear whether this is a traditional or modern unit, (though itʼs 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. :-)  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 peopleʼs 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 donʼt do it.

Or, as on some synths, e.g. Rolands, you could just have a transpose up/down switch and donʼt sweat the detail.  Assuming youʼre 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 havenʼt found a complete history of their use.