What Exactly is a Reed?

There is a lot of contention (that I created no doubt) on making a clear definition of a reed. Past definitions are far too ambiguous in my opinion and a rehashing of the definition and classification of reeds in is order. in 'hicks' Classification I completely redefine how wind instruments are classified where they only have a single common factor, the use of wind to generate their sound, with each type of generating force being unrelated. In these essay I will attempt to call out commonalities on how different solid materials generate a vibration that is typically carried into a column of air to make a pitched sound. In my definition something is a reed if it is capable of generating a regulated pitch in a tube and also if it is capable of generating pitch all on its own ( may later reclassify that later half of that).

The Previous Definitions of what a Reed is

Summarized from Wikipedia and Encyclopedia Britannica-
reed “A thin strip of material that vibrates to produce a sound on a musical instrument” “a thin blade of material typically a reed or thin metal that vibrates”

This definition has a major issue in that is describes single reeds (lamell reeds like those of a clarinet or saxophone) as well as free reeds (like those of a harmonica) but inadequacy describes the behavior of double reeds (or any other class listed above) because the focus is on the shape of the material.

My New Definition of what a Reed is

A reed is any solid material that vibrates in a stable and consistent manner in response to wind as the generating force of the oscillation. This is distinct from how flutes and how corrugation operates as the solid material these are made of is not required to vibrate for the instrument to operate, only the Air Column or Cavity Resonance is required. This definition includes anything that 'flaps' in response to an air pressure differential.

Understanding the Distinction Between the Two

For Reeds the following forces happen-
Wind –> Material that vibrates in response –> Sound is reinforced (or regulated) and directed by a resonating tube (air column with standing waves)

For flutes the process works as such-
Wind –> An edge that causes an oscillation –> Sound is generated in the Air Column with Standing Waves or in a Helmholtz Resonator with Cavity Resonance 1) 2)

With flutes and corrugation no material needs to vibrate in response to the agitation of the generation force, its the air itself that oscillates, not the solid material.

Things that I describe as a Reed


Free Reeds

Jaw Harp

I consider this to be an enclosed Free Reed, Hornbostel and Sachs consider this to be a Lamellophone which is only sometimes true when plucked. The movement of air is clearly the same behavior as other free reeds, with the mouth acting as the resonator, with the pitch of the lamell staying the same and the mouth altering the resonation of various harmonics of it. In this case the mouth is a hemholtz resonator, but sadly the sound regulation is not a vessel sound (which it would be cool if it were)

Plate Free Reeds

accordion, harmonica, melodica, most reed organ stops, possibly sheng, all Enclosed (sheltered on either side, transverse to the direction of intended vibration) Free Reeds, neither open or closed, and effected by either direction of airflow. This class is specific to the pitch being defined by the resonating frequency of the reed itself and NOT by regulation from a tube. Though these can have resonators.

Regulated (reinforced?) free reeds

Like the hulusi, bawu and some organ stops, claviola. Possibly also sheng and khean. These reeds are regulated by tube length and its not just acting as a resonator but instead determining pitch (as seen by the ability to change pitch by opening and closing tone holes. If it were purely a resonator the pitch of the pipe would need to match the resonate pitch of the reed, or a harmonic of it. The pitch generated by the tube causes the reed to vibrate at the same pitch, even when the reed has its own separate resonate frequency.

Drag Reeds

Warpable/flexable/elastic lamell reed, also called a limp lamell

an unenclosed free reed that is made out of a strip of highly flexible material and vibrates in response to being dragged by parallel wind force, this generates a longitudinal and torsional and transverse vibrations all at the same time. can be inside a tube which an change pitch only via the resonation of the tube not by regulation of the strip (the strip only agitates the air in the tube without the reed vibrating at the resonate frequency of the tube itself. Energy is exchanged between the reed and the walls of a tube (if present) or also from the reed and the drag of air (when tube isnt present). These reeds are not capable of generating a stable pitch (consonance) and are not capable of regulation

Pressure Closed Lamells

Lamell Reeds/Mouthpiece Reeds

Clarinet or saxophone Reeds, where a lamell beats against a rigid material called the mouthpiece (damping occurs), the reed is forced closed by air pressure. Cyclical vibration is reinforced by the exchange of energy between the reed and the mouthpiece causing the back and forth cycle to be uneven (the reed beats a shorter distance to reach the mouthpiece surface and bounces back in the opposite direction far further because of the additional energy from the collision, returning back after the elastic force of the material exceeds the energy exchanged. This system causes a very strong cycle that exceeds the strength of the cycles with a free reed, allowing it to more easily be regulated by a tube and to play a much larger range of pitches.

Double lamell Reeds

A similar system but two parallel but very closely spaces lamells beat against one another when air pressure is applied. This system is very similar in appearance to double reeds but distinct for reasons discussed below. The benefits of having an energy exchange with a surface are gained with the added benefit that both surfaces are vibrating and not damped. No known example of this exact system are known where the free end of the reed (not the mounted side) faces the direction of the incoming wind (points like a regular reed) but it is possible. i have built examples of the opposite where the drag of the wind forces the two reeds together and starts the cycle, in this sense the reeds are backwards in the system. This resembles the elastic ribbon reeds mentioned above but functions differently because the reeds are rigid and slap open and closed in a controlled manner and is capable of generating stable pitch and capable of pitch regulation. I question if pressure closes these reeds or if drag closes them.

Pressure Opened Lamells

Drawn Lamell/Invert Mouthpiece Reeds

This is the invert of a lamell reed, where instead of air forcing the reed against the mouthpiece to start the energy exchange, the reed rests against the mouthpiece and is forced apart by air. This requires the reed to be reversed in direction compared to the direction of typical reeds (pressure opens the system not closes it) so the reed appears to be backwards to a normal reed. This system is opened by pressure and not drag. This is seen on some horns such as historic car horns. This system accepts regulation and the reed will match the pitch of a pipe. by definition these reeds have to be reedcap instruments as there can be no regulation by lips (which only work by narrowing the distance on single reeds).

Drawn Double Lamell Reeds

Two parallel lamells that are touching separate through the drag of air flowing parallel between them, capable of pitch regulation with a tube, needs to be inserted into the tube much like the drawn lamell. Both air pressure and drag seem to be factors in this reed working, as they are touching and need separated by pressure but also are seemingly effected by drag.

Double Reeds

Pressure Closed Double Reeds

Double Reeds

Oboe, Shawm, Bassoon, these are two framed membranes with a small edge that is open. (in this case 3 sides of the reed have damped framed edges, and they have one open edge where vibration is allowed) Is forced closed by air pressure, beat against one another only at the opening edge. The distinction here is that both membranes beat at an single edge and are damped on all others, with nothing being beyond that edge. both sides beat against one another without them being lamells meaning its a double reed.

Crushed Double Reeds

Duduk, Guanzi, Hichiriki, two membranes that have a narrow slot opening that vibrate against one another in a linear fashion. The action of crushing these reeds is a form of regulation where the edge of the reed is damped causing some of the vibration to move to the column of the reed. This change causes only the two side edges to be fully damped, with the bottom and top of the area of vibration only partially damped. This is the perfect point between forced open and forced closed by air as the restriction point may be forced open but the edge of the reed is forced closed, and the reed remains in the same position (not inverted or reversed) and a typical double reed.

Pressure Opened Double Reeds


Lips playing into a brass instrument (these are invert because its two edges that are forced open by air pressure instead of forced closed like on a double reed). This class is used for edges that are limp and flexible like lips because the action is quite different than on rigid examples (rigid are able to have different nodes in this case).

Crushed Tubular Reeds

When a segment of tubing that is flexible has a clamped restriction produced in or near the center that vibrates from wind passing through the restriction, with the walls in that restriction beat against one another. There is material both before and after the area of vibration. This is similar to a crushed double reed but none of the motion of movement takes place at the edge but instead in balanced system where the top and bottom beyond the vibration point are not able to move (movement only happens at the pinch point). This pinch point produces two moveable sides that beat against one another in the system, without there being any lamells meaning its a double reed.

Invert reeds

The same as above but rigid material is used. In this case pressure opens them as well as having the vibrating action at an edge, like that of standard double reeds. these would look like usual double reeds that are closed, and reversed in direction. Capable of pitch regulation.

Linear (Longitudinal?) Invert Reed

Examples include binder clips- the opening edge where vibration happens of the reed is extremely long and pitch can be generated from the internal cavity and by the length of the opening that vibrates (wider wings on the reed take longer amounts of time to cycle). This is very similar to the function of invert reeds like lips listed above but it has a different way of modulating pitch where the overall length of the reeds opening can determine pitch instead of the case of lips where the tension of the closed edge (a type of Regulation). The vibration may warrant a type of longitudinal vibration, which would explain why it cannot be regulated by the use of a tube. In theory a Pressure closed version of this reed could be made if it were entirely encapsulated into a windcap and directed into a narrow tube (for resistance).

Contentious Examples

Idiophone Reeds

Bullroarer- Called a Unenclosed Free Reed, I find describing this as a reed dubious, as it either acting as a string mount for the rope (source of agitation for the string) or a idiophone of some sort.

Ribbon Reeds

Grass Blade- This is a Air activated ribbon (a type of string) that is mounted on both sides, vibrates when air drags against the ribbon causing it to have torsional vibration. This type of reed is rather poorly understood for how common the use of grass blades are. Without a tube this reed can be tuned to play many pitches depending on the string tension, just like typical string instruments. I am unsure if this type of reed can be made without a ribbon shape (a round string instead) it seems unlikely that it would work as well (strongly suggesting torsional motion). I am also unsure if a reinforcement system using tubes is possible.

Membrane Reeds

Membranophone- A double chamber where air passes from the outer chamber into the inner chamber which is typically a tube by forcing open a membrane that is under tension, membrane beats against the tube, requires some kind of pitch reinforcement to work at all. Works with both cylinders as well as cones (though not well with wide cones). I consider this definitely a reed, it is similar to how a double reed uses a surface with 3 sides mounted, but this version has all sides mounted. Perhaps it is comparable to a single reed version of a double reed in that sense. These are also capable of being made with rigid materials, though the pressure required is quite high. I am using the term membrane the same as how i use it on resonator chambers on string instruments.


This page is still messy, the restructuring of wind families has led to a lot of things needing new terms (like labrophone vs invert reed, vs ribbon reed/regulation vs reinforcement and all that) and the terms are unresolved. I would like to just come up with one and call it a day, but i am still finding examples of prior works that have better terminology (for instance ribbon reed is coined by Jeremy Montagu).

I find it to be a source of some frustration that it seems there is no one (that I can find) critically asking what a reed is. It seems like an excellent question in terms of how we discuss instruments, It also seems that not even Hornbostel and Sachs (and updated versions of Systematik) have a definitive answer of any sort. It seems I am the first person to ask this question critically, generate a somewhat exhaustive list of options and to suggest any new definitions. I imagine the overall response to this expansion of the definition of a reed will be met poorly, as it suggests a much more broad classification and really reveals the tenuous ways wind instruments, woodwinds and brass are conflated categories and that the real distinction seems that all winds are divided into reed instruments (anything with a solid material that vibrates in response to wind) and all other wind instruments (edges and corrugation) which have no solid required to vibrate to make sound.

The use of the word 'reed' should perhaps be phased out. I find it contentious to name a set of phenomena after a material (one of many) that it is made out of. This of course carries over to other classes such as brass for brass instruments and wood in woodwind instruments.

It seems there is a ongoing consensus that the lips are not reeds by virtue that they are attached to the body, and not to the instrument. I find this distinction to be interesting as it is true the lips are only in contact with the instrument while playing, but they are also the physical source of the vibration. Similar could be said about lips being essential to many other winds such as the clarinet in the context of pitch regulation (which they also serve as such in brass instruments). I would counter this idea by the fact that a sort of artificial lips can be made 3) and used to play brass instruments (robots can in fact play brass instruments using silicone or latex 4) lips5)), and of course these synthetic ones are reeds in a more obvious sense, and can even be attached to the instrument in a more permanent way, negating the idea that lips are somehow exempt from being reeds for that reason.

Another distinction is that reeds need to be rigid, and that warpable and stretchable materials dont count. This is similar to the ideas of membranes vs soundboards on string instruments. I take the same solution considering both the same thing (in the case of strings, both are membranes, one rigid and the other warpable). these distinctions are just describing materials that are or near opposite sides of a spectrum. I think the only distinction is to define them by the opposites, or by the difference of the material behavior (with options in the middle being allowed to be intermediate and there being no hard cutoff). with that said there is no way to form a clear delineation between materials that easily bend and warp and ones that resist the action other than that they tend to have different timbre, and the more bendable they are the less upper harmonics they allow (a kind of self damping harmonic filter?) (then again that also happens when lips dampen the rigid material anyways)

reeds.txt · Last modified: 2024/03/06 17:37 by mete
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