A reed is a thin strip of material which vibrates to produce a sound on a musical instrument. The reeds of woodwind instruments are made from Arundo donax or synthetic material; tuned reeds (as in harmonicas and accordions) are made of metal or synthetics.
Single reeds are used on the mouthpieces of clarinets and saxophones. They have a flat (back) side which fits against the mouthpiece and a top side which tapers to a thin tip. They are rectangular in shape except for the thin vibrating tip, which is curved to match the curve of the mouthpiece tip. Although all single reeds are shaped similarly, they vary in size to fit the appropriate mouthpiece.
The most obvious variation in reeds designed for the same instrument is a variation in thickness ("hardness" or "strength"), generally measured on a scale of 1 through 5 from softest to hardest. This is not a standardized scale and reed strengths vary between manufacturers. The thickness of the tip and heel and the profile in between also affect the sound and playability. Cane of different grades (density, stiffness), even if cut with the same profile, will also respond differently.
Bassoon double reeds.Double reeds are used on the bassoon, oboe, bagpipes, tromboon, english horn, and some organs, where the reed goes in the player's mouth. They are typically not used in conjunction with a mouthpiece; rather the two reeds vibrate against each other. However, in the case of the crumhorn and shawm, a reed cap that contains an airway is placed over the reeds and blown without the reeds actually coming in contact with the player's mouth. Reed strengths are graded from 1 through 5, as with single reeds.
Most reeds are made from cane, but synthetic reeds made from various substances are used by a small number of clarinetists and saxophonists. Synthetic reeds are generally more durable than their natural counterparts, do not need to be moistened prior to playing, and can be more consistent in quality. Many players consider them to have poor sound, or use them only in a context where tone quality is less important, such as a marching band.
Recent developments in synthetic reed technology have produced reeds made from synthetic polymer compounds, and as technology in this area has progressed, synthetic reeds have gained more acceptance. Synthetic reeds are useful when the instrument is played intermittently with long breaks in between, during which time a natural reed might become dry.
The dizi, a Chinese transverse flute, has a distinctive kind of reed (a di mo), which is made from a paper-like bamboo membrane.
Musicians originally crafted reeds from cane using simple tools, a process which was time-consuming and painstaking. Specialized tools for cutting and trimming reeds by hand reduce the time needed to finish a reed.
Today, nearly all players of single-reed instruments buy manufactured reeds, although many players adjust them by shaving or sanding. Some professionals make single reeds from "blanks", but this is time-consuming and can require expensive equipment.
Among double reed players, advanced and professional players typically make their own reeds, while beginners and students often buy reeds either from their teachers or from commercial sources.