Double reed


A double reed is a type of reed used to produce sound in various wind instruments. In contrast with a single reed instrument, where the instrument is played by channeling air against one piece of cane which vibrates against the mouthpiece and creates a sound, a double reed features two pieces of cane vibrating against each other. The term double reeds can also refer collectively to the class of instruments which use double reeds. The timbre of a single and double reed instrument is related to the harmonic series but only including only the odd harmonics due to air column modes canceling out the even harmonics. This may be compared to the timbre of a square wave.

Construction

There are several differences, the most obvious being size, between various types of double reeds, for example between that for a bassoon and that for an oboe or a cor anglais.
Typically, Arundo donax cane is used for the making of double reeds. For bassoon reeds, tubes of this cane are first split lengthwise then gouged to a certain thickness. The chosen piece of cane is then cut to shape and the centre portion is thinned. The cane is folded end to end to form the two blades of the reed. The unprofiled end of the cane is shaped into a tube with the aid of a mandrel and bound with three strategically placed wires. A turban made out of thread is added on the third wire. It provides a hand hold for the reed that is not a sharp wire. The folded tip is cut off to allow the blades to vibrate and final adjustments to the interior of the reed using a reamer, and to the exterior using a reed-scraping knife, are carried out. The reed is then ready to fit to the bocal of the bassoon.
The construction of double reeds for the oboe family of instruments is similar in principle: like the bassoon's reeds, they consist of two pieces of Arundo donax cane fastened together with an opening at the tip. However, because the oboe does not have a bocal, the cane must be fastened to a metal tube, the lower half of which is normally surrounded by a piece of cork. The staple is then inserted into the farrow at the upper end of the oboe.
Players can buy reeds either ready-made, or in various stages of formation, such as part-scraped, reed blanks, or buy the staples and cane separately. Cane is sold in several forms: as tubes, gouged, gouged and shaped, or gouged and shaped and profiled. Bassoon cane has the further option of being profiled before purchase. Cane from several different regions is used in reed making, traditionally from southern France. There are also many options with regard to staples, shaping equipment, and so forth, which all have a subtle effect on the tone quality a reed will produce.
There is a great deal of variation in respect to the construction of reeds; both in terms of the methodology of their creation and in terms of what a finished reed ought to look or sound like, and reedmaking culture varies between countries, cities, and individuals.
Oboe reeds are usually about 7 mm in width, and bassoon double reeds are wider than oboe double reeds with a width anywhere from 13.5–15.9 mm. The width of a reed affects its sound and response, and so many reed makers variate it to achieve the results they desire. Reed length, which broadly affects pitch, is much less consistent globally, as different orchestras tune to different frequencies. Auxiliary double reeds such as English horn and contrabassoon have their own sets of measurements, which are, again, subject to the requirements of the player.
Differences in reed construction can have a substantial impact on the sound produced by the reed, and as a consequence professional double reed players must exercise meticulous craftsmanship in creating a suitable-sounding reed for whatever repertoire they are playing, with yet further considerations such as whether the player is principal or sectional, whether the reed will be suitable for every item on the program, et cetera. Environmental factors such as humidity and temperature also affect the performance of a double reed. Adjustments to reeds are, consequently, very frequent among double reed musicians.

Other reed materials

While cane is by far the most common material for double reeds, it is possible to make reeds from other materials. Reeds made out of synthetic materials may be used; these reeds often last longer and are less sensitive to temperature and humidity fluctuations. Most reeds produced from synthetic materials have a tone quality that is dissimilar to that of a cane reed and are not favored by musicians. However, some recent manufacturers produce synthetic reeds that are used in a professional setting.

Playing a double reed

The orchestral double reeds all employ a similar embouchure. Players pull their lips over their teeth to protect the reed from their teeth, and then excite the blades of the reed by blowing, while controlling the timbre and pitch with constant micromuscular pressure adjustments from the muscles of the mouth and jaw. Articulation is achieved by occluding the mouth of the reed with the tongue and then releasing it, with extended techniques such as double tongue, flutter tongue and growl all possible as on the other woodwind families.
The principal difference between double reed embouchures - both between and within instrument families - is in the positioning of the rolled-in lips, and the musculature employed to control a sound. Oboe reeds, being much longer relative to their width, require concentrated pressure near the tip with more pressure from the sides of the mouth, whereas bassoon reeds are played with lips slightly more pouted and not necessarily aligned vertically. All double reed players employ and develop muscles at the back of the mouth to control their intonation, via adjustments to the shape and pressure of the oral cavity surrounding the reed.

List of instruments which use double reeds

Main Western orchestral instruments

Instruments where the reed is fully enclosed in a windcap