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.