The Recent Revolution in Organ Building Part 7

The top end is not stopped with a cork, as in the ordinary Flute, but is thinned off to a feather edge, leaving a sharp circular ring at right angles to the axis of the bore. By blowing across this ring a fair but somewhat feeble Flute tone is produced.

The six holes being closed by the fingers, the ground tone of the tube is produced. On lifting the fingers in successive order from the bottom end, we get the seven notes of the major scale. Closing the holes again and blowing harder, we get the scale _an octave higher_.

By blowing still harder we get an octave higher still. In other words, we are now producing _harmonics_.

It is possible to produce from a plain tube without finger-holes or valves, such as the French Horn, by tightening the lips and increasing the pressure of the player's breath, the following series of harmonics:

[Ill.u.s.tration: Series of harmonics]

The harmonics of a pianoforte string can be easily demonstrated by the following experiment: Depress the "loud" pedal and strike any note in the ba.s.s a sharp blow. On listening intently, the 3d, 5th, and 8th (the common chord) of the note struck will be heard sounding all the way up for several octaves. In this case the other strings of the piano act as _resonators_, enabling the harmonics to be heard.

Coming back to our Flute again and applying the knowledge we have gained to an organ pipe, we observe:

1. That the _pitch_ of the sound depends on the length of the tube.

2. That the pitch of the sound _also_ depends on the amount of wind pressure.

From this last will be seen how important it is that the pressure of the wind in an organ should be steady and uniform. Otherwise the pipes will speak a harmonic instead of the sound intended--as, indeed, frequently happens.

When a stop is labeled "8 ft.," that means that the bottom pipe, CC is 8 feet long and the pitch will be that of the key struck. A "16-ft."

stop will sound an octave lower; a "4-ft." stop an octave higher.

These measurements refer to pipes which are open at the top and are only correct in the case of very narrow pipes, such as the stop called Dulciana. Wider pipes do not require to be so long in order to produce 8-ft. tone.

"If a tube * * * open at both ends be blown across at one end, the fundamental tone of the tube will be sounded; but if the hand be placed at one end of the tube, so as to effectually close it, and the open end be blown across as before, a sound will be heard exactly one octave below that which was heard when both ends of the tube were open. One of these pipes was an open pipe, the other a stopped pipe; and the difference between the two is that which const.i.tutes the two great cla.s.ses into which the flue pipes of organs are divided." [1]

Thus by stopping up the end of an organ pipe we get 8-ft. tone from a pipe only 4 ft. long, 16-ft. tone from a pipe 8 ft. long, and so on, but with loss of power and volume. The harmonics produced from stopped pipes are entirely different from those of the open ones; their harmonic scale is produced by vibrations which are as 1, 2, 3, 4, etc., those of a stopped pipe by vibrations which are as 1, 3, 5, 7. All these harmonics are also called upper partials.

The Estey Organ Company claim to have discovered a new principle in acoustics in their Open Ba.s.s pipes, of which we show a drawing opposite. This invention (by William E. Haskell) enables the builders to supply open ba.s.s tone in organ chambers and swell boxes where there is not room for full-length pipes.

[Ill.u.s.tration: Fig. 16. Estey's Open Ba.s.s Pipes--Wood and Metal]

Referring to the ill.u.s.tration, it will be seen that the pipes are partly open and partly stopped, with a tuning slide in the centre. The builders write as follows:

"The inserted tube, or complementing chamber, in the pipe is such in length as to complete the full length of the pipe. It is, as will be noted, smaller in scale than the outside pipe. The effect is to produce the vibration that would be obtained with a full-length pipe, and in no way does it interfere with the quality of tone. In fact, it a.s.sists the pipe materially in its speech. This is most noticeable in a pipe such as the 32-foot Open Diapason, which when made full length is quite likely to be slow in speech. With this arrangement the pipe takes its speech very readily and is no slower in taking its full speech than an ordinary 16-foot Open Diapason.

"We have worked this out for all cla.s.ses of tone--string, flute and diapason--and the law holds good in every instance."

Helmholtz was the first to demonstrate that the _quality_ of all musical tones depends entirely upon the presence or absence of their upper partials. In the hollow tone of the Flute they are almost entirely absent; in the clanging tone of the Trumpet many of the higher ones are present; and if we take an instrument like the Cymbals we get the whole of the upper lot altogether.

The different qualities of tone of the organ pipes are therefore determined: (1) By the material of which the pipes are made; (2) by the shape of the pipe; (3) by the amount of wind pressure; (4) by the shape and size of the mouth, the relation of the lip to the stream of wind impinging on it from a narrow slit, and the shape and thickness of the lip itself. The manipulation of the mouth and lip to produce the tone desired is called voicing and calls for considerable artistic skill.

The writer recollects an instance of a clever voicer (Gustav Schlette) taking a new organ in hand, which was not quite satisfactory, and on the following Sunday he hardly knew it again.

Another kind of harmonics must now be described, called combinational or Tartini tones (from Tartini, a celebrated Italian violinist of the XVII century, who first described them). "These tones," says Helmholtz, "are heard whenever two musical tones of different pitches are sounded together loudly and continuously." There is no necessity for giving a table of all of their tones here; we select the two most useful. If two notes at an interval of a fifth are held down, a note one octave below the lower one will be heard. So organ builders take two pipes--one 16 feet long (CCC) and one 10 2/3 feet long (GG)--which make the interval of the fifth, and, by sounding them together, produce the tone of a pipe 33 feet long (CCCC). This is the stop which will be found labeled "32-ft. Resultant." Hope-Jones makes a stop which he calls Gravissima, 64-ft. Resultant, in his large organs. Many contend that this system produces better results than if pipes of the actual lengths of 32 or 64 feet were employed. Indeed, a pipe 64 feet long would be inaudible; the human ear has its limitations and refuses to recognize tone lower than 32 feet (just as we cannot lift water by a suction pump over 32 feet)--_but_, these great pipes _produce harmonics_ which wonderfully reinforce the tone of the organ.

Therefore their use is worth while.

The other combinational tone to which we refer is that produced by the interval of a major third. It sounds two octaves below the lower note.

The writer is not aware that this has ever been used as an organ stop, but it is found written in the organ compositions of Guilmant and other first-rate composers. It will be seen that a skilful organist, with a knowledge of these tones, can produce effects from small organs not available to the ordinary player.

Reverting once more to our Flute, whose tube is shortened by lifting the fingers from the holes, it is not generally known that this can be done with an organ pipe; the writer has met with instances of it in England. The two lowest pipes of the Pedal Open Diapason were each made to give two notes by affixing a pneumatic valve near the top of the pipe. When the valve was closed the pipe gave CCC. When the organist played CCC sharp, wind was admitted to the valve, which opened, and this shortened the pipe. The device worked perfectly, only that it was not possible to hold down both CCC and CCC sharp and make "thunder"! The organist of Chester Cathedral had been playing his instrument twice daily for ten years before he found this out, and then he only discovered it when the pipes were taken down to be cleaned. It is an admirable makeshift where a builder is cramped for room.

Organ pipes are divided into three families--Flues, Reeds and Diaphones. The flues are subdivided into Diapasons, Flutes, and Strings, and we now proceed to consider each of these groups separately.

DIAPASONS.

The pipes usually seen in the front of an organ belong to the Great organ Open Diapason, long regarded as the foundation tone of the instrument. The Open Diapason may vary in size (or scale) from 9 inches diameter at CC to 3 inches. The average size is about 6 inches.

The Diapasons of the celebrated old organ-builders, Father Schmidt, Renatus Harris, Green, Snetzler and others, though small in power, were most musical in tone quality. Though sounding soft near the organ, the tone from these musical stops seems to suffer little loss when traveling to the end of quite a large building. About the year 1862 Schulze, in his celebrated organ at Doncaster, England, brought into prominence a new and much more brilliant and powerful Diapason. The mouths of the pipes were made very wide and they were more freely blown. Schulze's work was imitated by T. C. Lewis, of England, and by Willis. It has also exercised very great influence on the work done by almost all organ-builders in this country, in Germany, and elsewhere.

Schulze's method of treatment added largely to the a.s.sertiveness and power of the tone, but gave the impression of the pipes being overblown and led to the loss of the beautiful, musical, and singing quality of tone furnished by the older Diapasons. Hard-toned Diapasons became almost the accepted standard. Willis even went so far as to slot all of his Diapason pipes, and Cavaille-Coll sometimes adopted a similar practice. Walker, in England, and Henry Erben, in this country, continued to produce Diapasons having a larger percentage of foundation tone and they and a few other builders thus helped to keep alive the old traditions.

In the year 1887 Hope-Jones introduced his discovery that by leathering the lips of the Diapason pipes, narrowing their mouths, inverting their languids and increasing the thickness of the metal, the pipes could be voiced on 10, 20, or even 30-inch wind, without hardness of tone, forcing, or windiness being introduced. He ceased to restrict the toe of the pipe and did all his regulation at the flue.

His invention has proved of profound significance to the organ world.

The old musical quality, rich in foundation tone, is returning, but with added power. Its use, in place of the hard and empty-toned Diapasons to which we had perforce become accustomed, is rapidly growing. The organs in almost all parts of the world show the Hope-Jones influence. Few builders have failed now to adopt the leathered lip.

Wedgwood, in his "Dictionary of Organ Stops," pp. 44, 45, says:

"Mr. Ernest Skinner, an eminent American organ-builder,[2] likens the discovery of the leathered lip to the invention by Barker of the pneumatic lever, predicting that it will revolutionize organ tone as surely and completely as did the latter organ mechanism, an estimate which is by no means so exaggerated as might be supposed. The leathered Diapason, indeed, is now attaining a zenith of popularity both in England and America.[3] A prominent German builder also, who, on the author's recommendation, made trial of it, was so struck with the refined quality of tone that he forthwith signified his intention of adopting the process. A few isolated and unsuccessful experimental attempts at improving the tone of the pipes by coating their lips with paper, parchment, felt, and kindred substances, have been recorded, but undoubtedly the credit of having been the first to perceive the value and inner significance of the process must be accorded to Mr. Robert Hope-Jones. It was only at the cost of considerable thought and labour that he was able to develop his crude and embryonic scientific theory into a process which bids fair to transform modern organ building. The names of Cavaille-Coll and George Willis, and of Hope-Jones, will be handed down to posterity as the authors of the most valuable improvements in the domains of reed-voicing and flue-voicing, respectively, which have been witnessed in the present era of organ building."

The desire for power in Diapason tone first found expression in this country by the introduction into our larger organs of what was called a Stentorphone. This was a large metal Diapason of ordinary construction, voiced on heavy wind pressure. It was most harsh, unmusical and inartistic. It produced comparatively little foundation tone and a powerful chord of harmonics, many of them dissonant. In Germany, Weigle, of Stuttgart, introduced a similar stop, but actually exaggerated its want of refinement by making the mouth above the normal width. As knowledge of the Hope-Jones methods spreads, these coa.r.s.e and unmusical stops disappear. He is without question right in urging that the chief aim in using heavy pressure should be to increase refinement, not power of tone. Sweet foundation tone produced from heavy wind pressure always possesses satisfactory power. He is also unquestionably right in his contention that when great n.o.bility of foundation tone is required, Diapasons should not be unduly multiplied, but Tibias or large Flutes should be used behind them.

Every epoch-making innovation raises adversaries.

We learn from these that pure foundation tone does not blend. True, there are examples of organs where the true foundation tone exists but does not blend with the rest of the instrument, but it is misleading to say that "pure foundation tone does not blend." Hope-Jones has proved conclusively that by exercise of the requisite skill it does and so have others who follow in his steps. A view of the mouth of a Hope-Jones heavy pressure Diapason, with inverted languid, leather lip and clothed flue, is given in Figure 17.

[Ill.u.s.tration: Fig. 17. Diapason Pipe with Leathered Lip]

The dull tone of the old Diapasons was due to the absence of the upper harmonics or partials. With the introduction of the Lutheran chorale and congregational singing it was found that the existing organs could not make themselves heard above the voices. But it was discovered empirically that by adding their harmonics artificially the organs could be brightened up and even made to overpower large bodies of singers. Hence the introduction of the Mixture stops (also called compound stops), which were _compounded_ of several ranks of pipes.

The simplest form was the Doublette sounding the 15th and 22nd (the double and treble octave) of the note struck. Other ranks added sounded the 12th, 19th, and so on, until it was possible to obtain not only the full common chord, but also some of the higher harmonics dissonant to this chord, from a single key.

THE DECLINE OF MIXTURES.

Fifty years ago it was common to find the number of ranks of mixtures in an organ largely exceed the total number of foundation stops.

Mixtures were inserted in the pedal departments of all large organs.

Organists of the time do not seem to have objected and many of the leading players strongly opposed Hope-Jones when he came out as the champion of their abolition. These stops greatly excited the ire of Berlioz, who declaims against them in his celebrated work on orchestration.

The tone of these old organs, when all the Mixture work is drawn, is well nigh ludicrous to modern ears, and it is hard to suppress a smile when reading the statements and arguments advanced in favor of the retention of Mixtures by well-known organists of the last generation.

These mutation stops still have their place in large instruments, but it is no longer thought that they are necessary to support the singing of a congregation and that they should be voiced loudly. The decline of Mixture work has in itself entirely altered and very greatly improved the effect of organs when considered from a musical point of view. The tone is now bright and clear. Mr. James Wedgwood says:

"The tendency to exaggerate the 'upper work' of the organ reached a climax in the instrument built by Gabler, in 1750, for the Monastic Church at Weingarten, near Ravensburg. This organ comprised no less than ninety-five ranks of Mixture, including two stops of twenty-one and twenty ranks, respectively. Toward the close of the Eighteenth Century, the Abt Vogler (1749-1814) came forward with his 'Simplification System,' one feature of which consisted in the abolition of excessive Mixture work. The worthy Abbe, who was a capable theorist and a gifted player, and possessed of an eccentric and, therefore, attractive personality, secured many followers, who preached a crusade against Mixture work. The success of the movement can well be measured by the amount of apologetic literature it called forth, and by the fact that it stirred the theorists to ponder for themselves what really was the function of the Mixture. * * * The announcement by Mr. Hope-Jones at the beginning of the last decade of the past century of his complete discardment of all Mixture and mutation work may fairly be stated to have marked a distinct epoch in the history of the controversy."

It is indeed strange to find that this man, who did much to discourage the use of mixtures, has never quite abandoned their employment and is to-day the sole champion of double sets of mixture pipes, which he puts in his organs under the name of Mixture Celestes! However, these are very soft and are of course quite different in object and scope from the old-fashioned mixture--now happily extinct.

FLUTES.

The chief developments in Flutes that have taken place during the period under consideration are the popularization of the double length, or "Harmonic," principle,[4] by Cavaille-Coll, by William Thynne and others, and the introduction of large scale leather-lipped "Tibias" by Hope-Jones.

Harmonic Flutes, of double length open pipes,[5] are now utilized by almost all organ builders. Speaking generally, the tone is pure and possesses considerable carrying power. Thynne, in his Zauber Flote, introduced stopped pipes blown so as to produce their first harmonic (an interval of a twelfth from the ground tone). The tone is of quiet silvery beauty, but the stop does not seem to have been largely adopted by other builders. Perhaps the most beautiful stop of this kind produced by Thynne is the one in the remarkable organ in the home of Mr. J. Martin White, Balruddery, Dundee, Scotland.