_VOICING AND TUNING._
THE time has now come when we may bring our little organ into musical
order, and reap some of the fruits of our toil.
If the processes described in previous chapters have been steadily
carried out, the instrument is now complete (so far as the manual only
is concerned) with the exception of the draw-stop action, which we
intentionally reserve, and the external case.
We shall insert here, therefore, a few pages on voicing, the important
and delicate operation by which the correct speech and distinctive tone
of organ-pipes is imparted to them.
Let us warn the reader at once, and with emphasis, that the process
of voicing metal pipes is so complex that a complete mastery of its
practical details is by no means uniformly attained, even after years
of steady practice under skilled guidance. A very sensitive and
educated ear, a delicate sense of touch in the handling of fine tools,
and a thorough familiarity with the tonal quality, or _timbre_, of
the best examples of the many varieties of pipes--these gifts are
essential to the successful voicer. Hence we cannot counsel beginners
to attempt the voicing of metal pipes, unless they are fortunate enough
to find themselves in a position to obtain lessons from some clever
operator willing to give them, or unless they can gain permission to
attend at some first-class factory, for the express purpose of watching
the pipe-makers and voicers at work.
We shall not be deterred, however, by these considerations from
describing, to the best of our ability, the business of voicing and
regulating an ordinary metal pipe, pointing out specially, as we go
on, all that may be necessary for the removal of defects and faults in
pipes already voiced by other hands. But we must acknowledge our own
obligations to the little treatise on voicing and tuning mentioned in
the preface to this work. Those who obtain and peruse this thoroughly
practical little tract will find all the information which they can
require.
Figs. 40, 41 show the well-known forms of metal organ-pipes as seen
in the Open Diapason, Principal, &c. Figs. 42, 43 give details. The
languid, Fig. 42, is a little enlarged. It will be seen that the
essential features of wooden pipes have their counterpart in those of
metal--the language, or languid, answering to the wooden block, the
conical termination to the wooden pipe-foot, the cylindrical body to
the rectangular wooden tube.
[Illustration: Fig. 40.]
[Illustration: Fig. 41.]
[Illustration: Fig. 42.]
[Illustration: Fig. 43.]
We have never made any metal pipes ourselves, and we doubt if our
readers will do well to embark upon an undertaking requiring special
"plant" and appliances in a separate workshop, and calling for great
dexterity and neatness in a class of operations familiar only to
trained artisans. For the information, however, of those who choose to
make the experiment, we may explain that the metal sheets from which
the pipes are made are thus produced:--
"The ingredients (viz. tin and lead in various proportions) are melted
together in a copper and then cast into sheets, a process effected by
pouring it in a molten state into a wooden trough, and running the
trough rapidly along a bench faced with _tick_. The metal escapes from
the trough through a narrow horizontal opening at the back, leaving
a layer of metal behind it as it proceeds; and the wider the cutting
is, of course the thicker will be the sheet of metal produced. After
being cast to an approximate thickness, the metal is planed down to the
precise thickness required. It is then cut into portions of the shape
necessary to give to the pipes the required size and form, and is thus
finally worked up."[2]
[2] Hopkins and Rimbault, p. 76.
The three parts which compose the pipe are first separately prepared.
The sheet of metal is rolled round a wooden cylinder or cone, called a
mandrel, and the edges are soldered together. The extreme neatness of
this soldered joint is secured by smearing the metal with composition,
which is scraped off at that part only which is to retain the solder;
but a steady hand, and long familiarity with the manipulation of
the heated copper tool and with the properties of soft solder, are
absolutely essential to success.
At the lower part of the body thus soldered, the mouth is formed by
flattening a portion of the cylinder and by cutting away a horizontal
slip of the metal. The width of the mouth is to be in all cases a
quarter of the circumference of the pipe. In the case of large pipes
the mouth is formed by cutting away a piece of metal of considerable
size, and replacing it by a sheet called the "leaf," having the mouth
cut on its lower edge.
The foot is formed in a similar manner, and has a flattened portion
corresponding to that of the body.
The language, or languid, is a circular disc of much thicker stuff,
bevelled off round its periphery, which is altered into a straight
line at that portion which will lie beneath the mouth when the pipe is
complete.
The three component parts are thus worked together.
The languid is placed on the wide opening of the foot, and the windway
formed by leaving a narrow slit between the straight edge of the
languid and the flattened lip of the foot. The two are then neatly
soldered together. The body is then soldered to the foot, care being
taken to adjust the mouth exactly opposite to the windway.
The larger pipes have ears, namely, rectangular pieces of metal
soldered on each side of the mouth.
Thus completed and cleaned over, the pipes are handed to the voicer.
It will be remembered that we left a wooden pipe, similarly put
together but unvoiced, in an earlier portion of this book. We have
now to explain that both classes of pipes pass through a similar or
analogous course of treatment at the hands of the voicer.
With small metal tools, called notchers, of which he has four or five,
he cuts a row of nicks in the straight edge of the languid, causing it
to resemble somewhat the edge of a saw. These nicks or notches, coarse
or fine, close together or at rarer intervals, as the case may be,
conduct the sheet of wind from the foot-hole against the upper lip of
the mouth, and influence to a most important extent the character of
the tone.
In a similar way, and using a file ground to a saw-like edge, the
operator on a wooden pipe cuts nicks in the slightly bevelled upper
edge of the block, and continues or prolongs these notches obliquely
across the front of the block, letting them die away or come to nothing
at their extremity. Fig. 44 shows the front of a block thus treated.
[Illustration: Fig. 44.]
The art of the voicer, however, is by no means expended upon this
notching of the languids and blocks. It extends to the accurate and
nice adjustment of the height of the mouth, the aperture of the
foot-hole, and the width of the windway. All these will bear strict
proportion to the scale or size of the body of the pipe, and to the
weight or pressure of the wind.
It will be seen, therefore, that the tone, quality, or _timbre_ of an
organ-pipe, and therefore of a "stop" or set of organ-pipes, depends
upon skilled attention to at least six distinct considerations, viz.:--
_a._ Scale of pipe.
_b._ Height of mouth.
_c._ Diameter of foot-hole.
_d._ Width of windway.
_e._ Character of notching.
_f._ Weight of wind.
It is the thorough mastery of the art of manipulating pipes, with
all these essential points kept in view, which enables the voicer to
produce the exquisite contrasts of tone heard in good organs between
the tranquil Dulciana and the delicate Salcional; between the Violin
Diapason and the Gamba; between the Keraulophon and the Viola, as
variously constructed; between the fluty-toned stops, of wood or of
metal, to which various names have been given: and the full chorus
or combined power of a large instrument will be majestic, imposing,
and dignified, or, on the other hand, shrill, harsh, and unpleasing
(quality of materials being assumed to be similar), in proportion to
the skill, taste, and judgment with which it is finally voiced and
regulated.
We have said enough, perhaps, to justify our advice that metal pipes be
procured in a finished condition from competent makers.
Our little organ contains two metal stops, viz. a Dulciana (or a small
Open Diapason) from Tenor C to f in alt, and a Principal of 4 feet
throughout. Each of these, made of good metal, should cost £6 or £7.
Cheap pipes mean inferior metal, and this we cannot recommend in any
organ, great or small. The nearer the approach made to pure tin the
better (other essential points being assumed) will be the quality of
the tone.
In ordering the pipes, the weight or pressure of wind on which they are
to speak must be carefully specified. This may be easily ascertained
by using a wind-gauge, a little instrument which we sketch in its
simplest form in Fig. 45. It consists of a glass tube, bent as shown
in the figure (this can be done at any glass-blower's or optician's),
and having its lower end inserted in a wooden pipe-foot. Planting the
gauge on any hole of full size in any part of the sound-board, we pour
a little water into the bent part or dip of the gauge. On blowing the
bellows steadily, and depressing the key on the manual corresponding to
the groove on which the gauge is placed, the water will be depressed in
the inner column, and will rise in the outer. By adjusting the weights
on the bellows we may make this difference in the levels of the two
columns greater or less as we please. In our organ we shall have a
"2-inch wind;" that is to say, we shall load the bellows so that the
gauge may indicate a difference of 2 inches between the two columns.
[Illustration: Fig. 45.]
We may note here that about 7 lbs. per square foot of surface of
top-board will be required to give this pressure. Pieces of old cast
iron about an inch thick may be procured at any foundry, and form the
most suitable material for weights.
The voicer having worked to a 2-inch wind, it is probable that when
the new metal pipes are planted in their places they will speak
with charming evenness and truth. If some or any of them, however,
betray some defects, it will be well not to meddle with them until we
have satisfied ourselves that the fault does not belong to our own
mechanism. If, for instance, one pipe should be softer or less prompt
and clear than the others, let us be sure that the flow of wind to that
pipe is not interrupted or throttled by a chip in the wind-hole or
(if there is conveyancing) in the channel. This will be ascertained by
planting the pipe for the moment on some other groove than its own. If
the holes and channels are all clear, and the pallet is opened freely
by the key, the fault must be in the pipe. This may have suffered some
little injury in the packing case, _e.g._ the lower lip may have been
nipped too close to the edge of the languid, thus reducing the width of
the windway. This may be carefully rectified with the flat blade of a
common table-knife, or similar object. Or the languid itself may have
been bent or depressed by the weight of another pipe, packed within it
to save room in the case. If this is so, the languid must be carefully
pushed back to the level by a stout wire or rod inserted through the
foot-hole. If the _upper_ lip has been pressed inwards, we must counsel
the utmost care in bringing it back to its position. The pipe should be
sent back to the maker if the distortion is serious or considerable. If
it is slight we may rectify it by passing a slip of iron bent into the
shape of the letter =L= through the mouth, and thus pulling forward the
whole of the lower par of the "leaf," preserving its regular slope as
before. If the mouth, lips, and languid are all right, it is possible
that by some accident the size of the foot-hole has been reduced. It
may be cautiously enlarged with a penknife or with a broach; and if
under other circumstances the foot-hole requires reduction, this maybe
done by gently rapping or hammering the metal round the aperture with
the flat side of a chisel. The builders have a heavy brass cone for
effecting this reduction called a "knocking-up cup." Similar brass
cones, we may here add, are used in tuning. They are expensive, however.
All that we have said of possible defects in metal pipes applies,
_mutatis mutandis_, to wooden pipes; and as we make these ourselves we
may deal more boldly with them.
An unvoiced wooden pipe will generally emit a chirp or whistle before
its note. The nicking of the block will remove this, but if we overdo
this nicking we shall hear a huskiness or buzzing equally or more
disagreeable. This husky quality may also be due to a too wide windway;
in this case, remove the cap and rub the inside face of it on a sheet
of glass-paper pinned down upon a board, or plane off the inside face
and file the windway anew. If the mouth has been cut too high, there
may be nothing for it but to take off the front board and remake the
pipe. If the pipe, in other respects good, is too loud, plug the
foot-hole with neat flat plugs. If it is too soft, the pipe-foot may
have been imperfectly bored, or may be defective in some way, or chips
may have been left in the throat of the pipe. Ill-fitting stoppers
are a fruitful source of defects in wooden stopped pipes. Refit them
in every case of doubt, and leave no room for misgivings as to the
soundness of the joints of the pipe near the top.
We must point out to our readers that strength, sonority, or power
must on no account be expected from wooden pipes. A tone utterly harsh
and intolerable will be the result of over-blowing the Stopped Diapason
or Flute, stops of which the characteristic quality should only be
tranquil sweetness and softness. The flute of 4-feet tone, especially,
cannot be too delicate, and in its upper octave great patience will be
requisite in the adjustment of the tiny mouths and windways to prevent
shrillness.
These remarks apply also to our fifth stop, which we have been content
hitherto to call simply "Fifteenth" 2-feet. The Fifteenth proper is
a metal stop of strong shrill quality, having its value in large
instruments, where it is balanced by other stops in affinity with it.
Such a stop would be quite unsuitable to our little organ. If we are to
have a 2-feet stop at all, it should be a "Flageolet" or "Flautina,"
an echo, in fact, of the 4-feet Flute. This may be successfully made
by diligent operators in wood, the lower part stopped, the upper part
open. The professional voicers produce the fluty quality from ordinary
metal Fifteenths by peculiar treatment of the mouth. In foreign organs
such stops are generally or often of conical form, the narrow aperture
at the top. These stops (which may also be of 4-feet or 8-feet pitch)
usually bear the names "Gems-horn" or "Spitz-flute."
We may dismiss the subject of Tuning with a very few remarks. The
general principles of Temperament--that is to say, of the compromise
or adaptation requisite in the modern scale of an octave containing
twelve semitones--are not peculiar to organs, and may be studied in
any treatise. Mr. Hopkins exhausts the subject in a very interesting
chapter of his great work. Our useful little tract on voicing gives
all needful information. A sensible and practical pamphlet on the same
subject has been published by Mr. Hemstock, organist of Diss.
You will begin with Regulation, that is, with equalising the power or
strength of the pipes composing each stop. Bestow every care on this,
especially in the upper ranges of the small wooden pipes. The pleasing
effect of the organ will greatly depend upon success in this operation.
When satisfied on this point, tune your wooden pipes to the metal
Principal, which has been sent from the maker's ready tuned and voiced.
After this rough approximation to absolute correctness, go over the
whole organ with great deliberation and care, following the rules given
in the works which we have cited, or in any one of them. A second or
third tuning may be requisite before a sensitive ear is quite satisfied.
Cones and cups of boxwood, or made of sheet copper with brazed seams,
may be used in the absence of the expensive cast-brass articles.