Orgue portatif avec double soufflet

[Dominique Gatté]

Bonjour, quelqu'un peut-il me donner une explication au double soufflet de cet orgue ?

London, British Library, Add MS 38120, 103r

[Michael Shields]

Dear Nicolas,

Many thanks for your help, and helpful doubt. I know and admire Mark Lindley's observation of near-pure thirds over D, A, E in a Pythagorean tuning and their use in some music examples. I think he is still talking about a strict Pythagorean tuning (wolf H: F#) with some useable pure thirds in the black notes, but pure untempered fifths (at most, Lindley suggests one should take care that the fifths are not tuned wide). 

I am  interested in just tunings, with pure thirds and fifths on the white notes in the more common keys, over C, D, G or possibly F, and with resulting wolf intervals elsewhere - similar to those found in the two Heilsbronn (so-called Erlangen tunings, Erlangen Universitätsbibliothek MS 554) clavichord tunings with wolf A:E (method 1) or wolf  A:D (method 2).  Players on instruments tuned in these would either have to avoid using the wolf fourths and fifths as consonances, or adjust the pitch in some way, or maybe use the wolf vibrato in the low notes for expressive effect. I would imagine such tunings being used as an occasional alternative to pythagorean tunings.

So my question is really: When a 15th-century portative organ, pre-tuned in a just intonation (eg. with triads CEG, DFA and GHD pure and wolf A:E), is used as a single-melody instrument, can one use varying pressure to adjust the pitch of one or two bad notes when needed? I think this would depend whether the pipes used were constructed to give variations in pitch (not just amplitude).

Maybe there is an article that discusses 15th-century organ pipe scaling/voicing and might help to answer this question? (I am not optimistic: the surviving information may be too ambiguous to interpret.) It would also be useful to know whether there are any textual descriptions or iconograpy of people tuning their portative organs as they did their harp.

 I would be grateful for bibliographical advice, or advice in the form of practical experience of small organs. I know of a number of 16th-century just tunings for organ, and these look like conservative survivals from a period before meantone became widespread.

Michael

[Nicolas Meeùs]

I have no experience of that, but I very much doubt it. On the one hand, bellows played by hand do not allow a very precise control of the pressure -- enough perhaps to produce some variation in the dynamics, but certainly not the precision needed to achieve just intonation. Besides, even in the early 15th century, organs may have been tuned in some kind of meantone tuning, with the sharps (F#, C#, G# and even D#) almost pure major thirds above the diatonic D, A, E (and B). This tuning has been described among others by Mark Lindley. I could say more about it if needed.

Nicolas

Michael Shields said:

Can I ask whether you think that the dynamic possibilities could also be used to modulate pitch?

[Michael Shields]

Can I ask whether you think that the dynamic possibilities could also be used to modulate pitch? I am interested in the possibility that early 15th-century organists used just intonations with occasional modifications that might be achieved by air pressure.

Michael Shields, Galway/Ireland

[Nicolas Meeùs]

I think that the dynamic possibilities would remain even in a two-bellows instrument, as long as there is no regulating chamber and the bellows blow directly into the wind chest. Blowing a constant air supply with two bellows requires a good coordination of the hands, never blowing the two bellows together, but allowing no interruption at the change of bellow. But it must be possible to modulate the pressure.

It would normally also be possible to use only one of the two bellows, as Stefano da Verona's angel above apparently does. But the air supply could then not be continuous.

[Catalina Vicens]

 Here another example by Stefano da Verona (c 1374-1438). 

Yes, the two bellows would serve to have a constant air supply. It could be in fact a representation of a stylized version of a larger positive organ, although I have seen 'reconstructions' of organetti with two bellows (connected) an it does work (with only one player).

These two bellows mean a significant change of what we are now used to understand as the organetto and its musical capabilities/ limitations: an instrument which, because it does not have a constant air supply, has the need to 'breath' like a wind instrument or the voice; It has dynamic possibilities and fluctuation in pitch through the increase or decrease of pressure in the bellows. With the constant air supply of the two bellows, these characteristics are reduced or annulled.

I believe that Kimberly Marshall (1989), shows some depictions of organetti with two bellows.

[Nicolas Meeùs]

Deux éléments de réponse:

1) Les deux soufflets, utilisés chacun par une main en alternance, permettent d'assurer un souffle sans interruption alors que l'instrument ne possède sans doute pas de réservoir régulateur. (Dans les harmoniums, de même, les deux pédales s'utilisent des deux pieds en alternance).

2) Il faut néanmoins toujours se méfier des images d'orgues portatifs, qui représentent en général des instruments à peu près injouables, parce que trop grands, trop lourds, trop longs, trop larges. Ici par exemple, il faudrait une deuxième personne pour manoeuvrer les soufflets, ce qui rend la «portabilité» quelque peu illusoire...