CHAPTER VII.

MEANS OF OBTAINING EXPRESSION.

CRESCENDO PEDAL.

To most organs in this country, to many in Germany, and to a few in other countries, there is attached a balanced shoe pedal by movement of which the various stops and couplers in the organ are brought into action in due sequence. By this means an organist is enabled to build up the tone of his organ from the softest to the loudest without having to touch a single stop-knob, coupler or combination piston. The crescendo pedal, as it is called, is little used in England. It is the fashion there to regard it merely as a device to help an incompetent organist. It is contended that a crescendo pedal is most inartistic, as it is certain to be throwing on or taking off stops in the middle, instead of at the beginning or end of a musical phrase. In spite of this acknowledged defect, many of the best players in this country regard it as a legitimate and helpful device.

We believe the first balanced crescendo pedal in this country was put in the First Presbyterian Church organ at Syracuse, N. Y., by Steere, the builder of the instrument.

SFORZANDO PEDAL--DOUBLE TOUCH.

Under the name of Sforzando Coupler, the mechanism of which is described and illustrated in Stainer's Dictionary, a device was formerly found in some organs by which the keys of the Swell were caused to act upon the keys of the Great. The coupler being brought on and off by a pedal, sforzando effects could be produced, or the first beat in cadi measure strongly accented in the style of the orchestration of the great masters. Hope-Jones in his pioneer organ at St. John's Church, Birkenhead, England, provided a pedal which brought the Tuba on the Great organ. The pedal was thrown back by a spring on being released from the pressure of the foot. Some fine effects could be produced by this, but of course the whole keyboard was affected and only chords could be played. Various complicated devices to bring out a melody have been invented from time to time by various builders, but all have been superseded by the invention of the "Double Touch." On a keyboard provided with this device, extra pressure of the fingers causes the keys struck to fall an additional eighth inch (through a spring giving way), bringing the stops drawn on another manual into play. If playing on the Swell organ, the Choir stops will sound as well when the keys are struck with extra firmness; if playing on the Choir the Swell stops sound; and if playing on the Great the Double Touch usually brings on the Tuba or Trumpet. It is thus possible to play a hymn tune in four parts on the Swell and bring out the melody on the Choir Clarinet; to play on the Choir and bring out the melody on the Swell Vox Humana or Cornopean; or to play a fugue with the full power of the Great organ (except the Trumpet) and bring out the subject of the fugue every time it enters, whether in the soprano voice, the alto, tenor, or bass.

In the latest Hope-Jones organs arrangements are made for drawing many of the individual stops on the second touch, independently of the couplers.

BALANCED SWELL PEDAL

At the commencement of the period of which we are treating (some fifty years ago) the Swell shutters of almost all organs were made to fall shut of their own weight, or by means of a spring. The organist might leave his Swell-box shut or, by means of a catch on the pedal, hitch it full open.

When, however, he wanted the shutters in any intermediate position, he had to keep his foot on the pedal in order to prevent its closing.

The introduction of the balanced Swell pedal (Walcker, 1863) has greatly increased the tonal resources of the organ. It is used almost universally in this country, but strangely enough the country in which the Swell-box was invented (England, 1712) lags behind, and even to-day largely adheres to the old forms of spring pedal.

A further and great step in advance appears in recent organs built by the Hope-Jones Organ Company. The position of the swell shutters is brought under the control of the organist's fingers as well as his feet. Each balanced swell pedal is provided with an indicator key fixed on the under side of the ledge of the music desk, where it is most conspicuous to the eye of the performer. As the swell pedal is opened by the organist's foot, the indicator key travels in a downward direction to the extent of perhaps one inch and a quarter. As the organist closes his pedal, the indicator key again moves upward into its normal position. By means of this visible indicator key the organist is always aware of the position of the swell shutters. Through electric mechanism the indicator key is so connected with the swell pedal that the slightest urging of the key either upward or downward by the finger will shift the swell pedal and cause it to close or open as may be desired and to the desired extent. When an organ possesses four or five swell boxes, and when these swell boxes (as in the case of Hope-Jones' organs) modify the tone by many hundred per cent., it becomes highly important that the organist shall at all times have complete and instant control of the swell shutters and shall be conscious of their position without having to look below the keyboards. Hope-Jones also provides what he calls a general swell pedal. To this general swell pedal (and its corresponding indicator key) any or all of the other swell pedals may be coupled at will.

Hope-Jones has also recently invented a means of controlling the swell shutters from the manual keys to a sufficient extent to produce certain sforzando effects.

When this contrivance is brought into use upon any manual and when no keys upon that manual are being played, the swell shutters assume a position slightly more open than normal in relation to the position of the swell pedal. Directly any key upon the manual in question is depressed, the swell shutters again resume their normal position in relation to the swell pedal. This results in a certain emphasis or attack at the commencement of each phrase or note that is akin to the effect obtained from many of the instruments of the orchestra.

These contrivances are applicable only to such organs as have the balanced swell pedal.

SWELL BOXES.

The invention of the Swell is generally attributed to Abraham Jordan. He exhibited what was known as the nag's head Swell in St. Magnus' Church, London, England, in the year 1731.

The "nag's head" Swell, with its great sliding shutter, rapidly gave place to the "Venetian" Swell shades, used almost universally to this day. At the beginning of the period under consideration Swell boxes were almost invariably made of thin boards and their effect upon the strength of the tone was small. Willis was one of the first to realize the artistic possibilities of the Swell organ and in almost all his organs we find thick wooden boxes and carefully fitted shutters, and often an inner swell box containing the delicate reeds, such as the Vox Humana and Oboe.

Many of the leading organ builders now employ this thicker construction, and it is no uncommon thing to find Swell boxes measuring three inches in thickness and "deadened" with sawdust or shavings between the layers of wood of which they are formed.

A few organs of Hutchings and other makers are provided with a double set of shutters, so that sound waves escaping through the first set are largely arrested by the second. The _crescendo_ and _diminuendo_ are thus somewhat improved.

By the adoption of scientific principles Hope-Jones has multiplied the efficiency of Swell boxes tenfold. He points out that wood, hitherto used in their construction, is one of the best known conductors of sound and should, therefore, not be employed. The effects produced by his brick, stone and cement boxes (Worcester Cathedral, England; McEwan Hall, Edinburgh, Scotland, Ocean Grove, New Jersey, etc.) mark the dawn of a new era in Swell-box construction and effect. It is now possible to produce by means of scientific Swell boxes an increase or diminution of tone amounting to many hundred per cent.

We have heard the great Tuba at Ocean Grove, on 50-inch wind pressure, so reduced in strength that it formed an effective accompaniment to the tones of a single voice.

The Hope-Jones method seems to be to construct the box and its shutters (in laminated form) of brick, cement or other inert and non-porous material, and to substitute for the felt usually employed at the joints his patented "sound trap." This latter is so interesting and of such import in the history of organ building that we append, on the next page, illustrations and descriptions of the device.

If a man should stand at one end of the closed passage (C) he will be able to converse with a friend at the other end of the passage (D). The passage will in fact act as a large speaking tube and a conversation can be carried on between the two individuals, even in whispers (Figure 12).

This passage is analogous to the opening or nick between Swell shutters of the ordinary type.

If a man should stand in room 1 at A, he will be able to see a friend standing in room 4 at B, but the two friends will not be able to converse. When A speaks, the sound waves that he produces will spread out and will fill room 1. A very small percentage of them will strike the doorway or opening into room 2. In their turn these sound waves will be diffused all through room 2, and again but a small percentage of them will find access into room 3. The sound waves will by this time be so much attenuated that the voice of the man standing in room 1 will be lost. Any little tone, however, that may remain will become dissipated in room 3, and it will not be possible for a person standing in room 4 to hear the voice.

This plan illustrates the principle of the sound trap joint.

Figure 13 shows in section the joint between two Swell shutters. A small proportion of the sound waves from inside the Swell box striking the sound trap joint, as indicated by the arrow, will pass through the nick between the two shutters, but these sound waves will become greatly weakened in charging the groove A. Such of the sound waves is pass through the second nick will become attenuated in charging the chamber B. They will be further lost in the chamber C, and practically none will remain by the time the chamber D is reached.

It is Hope-Jones' habit to place the shutters immediately above the pipes themselves, so that when they are opened the Swell box is left practically without any top. It is in such cases not his custom to fit any shutters in the side or front of the Swell box.

To relieve the compression of the air caused by playing for any length of time with the shutters closed, he provides escape valves, opening outside the auditorium. He also provides fans for driving all the cold air out of the box before using the organ, thus equalizing the temperature with the air outside--or he accomplishes this result through the medium of gas, electric or steam heaters, governed by thermostats.

The Hope-Jones Vacuum Swell Shutters, with sound-trap joints, are shown in Figures 14 and 15.

It is well known that sound requires some medium to carry it. Readers will doubtless be familiar with the well-known experiment illustrating this point. An electric bell is placed under a glass dome. So long as the dome is filled with air the sound of the bell can be heard, but directly the air is pumped out silence results, even though it can be seen that the bell is continuously ringing. As there is no air surrounding the bell there is nothing to convey its vibrations to the ear.

That is why the hollow swell shutter, from the interior of which the air has been pumped out, is such a wonderful non-conductor of sound.

The shutters shown in Figures 14 and 15 are aluminum castings.

Ribs R|1| and R|2| are provided to support the flat sides against the pressure of the atmosphere, but each of these ribs is so arranged that it supports only one flat side and does not form a means of communication between one flat side and the other. Thus R|1| supports one flat side whilst R|2| supports the other. The aluminum shutters are supported by means of pivot P.

They are very light and can therefore be opened and closed with great rapidity.

A very thin vacuum shutter forms a better interrupter of sound waves than a brick wall two or three feet in thickness.

When partially exhausted the aluminum shutters are dipped into a bath of shellac. This effectually closes any microscopic blow-hole that may exist in the metal.

The use of Swell boxes of this vastly increased efficiency permits the employment of larger scales and heavier pressures for the pipes than could otherwise be used, and enormously increases the tonal flexibility of the organ.

It also does away with the need for soft stops in an organ, thus securing considerable economy. Where all the stops are inclosed in cement chambers (as in the case of recent Hope-Jones organs) and where the sound-trap shutters are employed, _every_ stop is potentially a soft stop.