We now come to the 15th century, which was prolific in its improvements of the springbox, keys, pedals, wind-supply, etc. And first of the Spring-box.
The first endeavour was to obtain more than one strength of tone from the same manual. It appears that to establish the power of preventing some of the sets of pipes (doubtless those that afterwards constituted the mixture and other bright-sounding ranks) from speaking when required to be silent, a sliding board was placed over the valves that opened and closed the entrance for the wind at the feet of those pipes. The remaining tiers of pipes, doubtless those sounding the unison (8), octave (4), and suboctave (16), could thus be left in readiness to sound alone when desired. The effect of this contrivance must have greatly resembled that of the 'shifting movement' of subsequent times.
Two distinct effects were thus obtained from one organ and one set of keys; and the question would soon arise, 'if two, why not more?' A further division of the organ-sound soon followed; and according to Prætorius the credit of first dividing and converting the Hintersatz into an Instrument of several single sets of pipes (afterwards called registers or stops) is due to a German artificer of the appropriate name of Timotheus, who constructed a soundboard possessing this power for an organ which he rebuilt for the monastery of the Bishop's palace at Würtzburg.
The 'Spring soundboard' was formed in the following manner. The valves of each note were closed in on each side by two diminutive walls (soundboard bars) extending from the back to the front of the wind-box, and, together with the top and bottom, forming and enclosing each valve within a separate canal (soundboard groove) of its own. The entire area of the former wind-box was partitioned off in this manner, and occupied by the 'bars' and 'grooves' of the newly devised soundboard. A playing-valve (soundboard pallet) was necessary below each groove to admit or exclude wind. These were collectively enclosed within a box (wind-chest) now added to fulfil the duty of the transformed wind-box. The valves immediately under the several pipes of a note were no longer drawn down from below by cords, but were pressed down from above, as shown in the following cut, which is a transverse section of a small spring soundboard for three stops.
Fig. 13.
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A metal pin passed down through the surface of the soundboard and rested on the front end of the 'register-valve' as it was called. A movement or draw-stop was provided, on drawing which the longitudinal row of metal pins was pressed down, and the valves lowered. The combined resistance of the set of springs beneath the valves was very considerable, hence great force was necessary in 'drawing a stop,' which had to be hitched on to an iron bar to keep it 'out.' When released it sprang back of its own accord. The set of pipes of which the register-valves were open, would then be ready for use; and in the woodcut the front set is shown as being thus prepared. The wind would be admitted into the groove by drawing down the soundboard pallet, which is seen immediately below.
By this means the power was created of using each separate set of pipes, except the small ones, singly or in any desired combination, so that the organ could be played loud or soft, or at any intermediate strength between the two extremes; and they now for the first time received distinctive names, as Principal (Open Diapason, 8 feet); Octave (Principal, 4 feet); Quint (Twelfth, 2⅔ feet); Super-octave (Fifteenth, 2 feet); etc.; and each separate series was then called a Register (Stop). The smaller sets of pipes were left to be used in a group, and were called 'Mixture'[1] (Sesquialtera, etc.). The stops sounding a note in accordance with the key struck, as C on the C key, were afterwards called Foundation-stops; those which produced a different sound, as G or E on the C key, were named Mutation-stops; while those that combined the two classes of sounds were distinguished as Compound or Mixture Stops.
The spring soundboard was much admired by some Hollanders; and some organ-builders from the Low Countries, as well as from Brabant, went to see it, and constructed soundboards on the same system for some time afterwards.
The pipe-work, however, was all of one class,—open, metal, cylindrical, and of full proportionate scale—similar in general model to the second great class of pipe referred to at the commencement of this article as Open. Great therefore as was the gain resulting from the invention of the registers, the tone still remained of one general character or quality. It then occurred to some of the thinking men of the time that other qualities of tone would probably ensue if modifications were made either in the shape, proportion, outline, or material of the pipes, etc.; and the experiments justified the hypothesis.
Stopped pipes (our first great class) were made either of wood closed with a plug, or of metal covered with a sliding cap; and so a soft pleasing mild tone was obtained. Thus originated the Gedact (Stopped Diapason), Bordun (Bourdon), Klein-gedact (Flute), etc. Some Reed-stops (our third class) were also invented about this time,
- ↑ Dr. Burney. Dr. Crotch, Kiesewetter, and other writers, took considerable pains to ventilate and enforce their various theories as to the origin of the Mixture-stop in an organ; but they all omitted to remember that for centuries the whole organ was nothing but one huge stop of the kind; and that when the larger sets of pipes were separated off for use, the Mixture was self-formed out of the residue, consisting of rows of little pipes that were thought scarcely worth the trouble of 'drawing on' separately.
