• Patrick Olwell

In the interest of clarity when discussing the details of wooden flute design, here are some terms that are common to both historical and contemporary wooden flutes and which we use in the making of our instruments...


The vertical interior surface of the mouth hole. The measurement of the height of this plane (from the interior of the bore to the outside surface of the instrument) is an important aspect of voicing a flute. Chimney height and the angle at which the chimney is cut have a lot to do with how the flute will sound and these designs have changed over time as wooden flutes have gradually shifted towards larger-diameter bores.


We use thin sheets of cork on the tenons, end-caps, plugs, and key bumpers of our flutes. The cork compresses to fill the space, allowing for a snug and airtight joint that has some necessary elasticity. Cork on tenons can become dry and brittle over time and should be periodically covered with a thin layer of cork grease to protect against drying out.


While in playing the flute, “embouchure” refers to the position of the player’s mouth, lips, tongue, and jaw, the term can also refer to the mouthpiece or—in the case of a wooden flute—the mouth hole of the flute. We use the term when discussing the characteristics of the mouth hole, including its size, shape, and position, and angle at which the chimney is cut.

The precise dimensions and shape of the embouchure have a significant impact on how a flute plays, and the ideal shape and proportion of an embouchure has long been the subject of debate. Many changes in embouchure shape have occurred over time as tastes have changed and players and makers have sought different acoustic characteristics in their instruments.


Turned out of wood to match the flute and corked to ensure a good fit with the headjoint, the end-cap covers the “top” of the flute and has a series of decorative concentric rings turned into its surface.


Note: in the context of flutes and other keyed wind instruments, “keys” can refer either to the hinged metal apparatuses that cover the tone holes and allows for the playing of sharps and flats or to the various key signatures associated with those notes.

Our “concert” keyless wooden flutes play easily in D and G Major and their related minors (Bm, Am, Em, etc.) As much of the traditional Irish music repertoire is in these keys, many players find a keyless flute to be sufficient for their needs. A keyed flute opens up many other possibilities for playing in keys that are outside this standard range. We also make flutes in the keys of Eb, Bb, and C.

We make both keyless and keyed flutes, with the keyed D models generally having six keys (C#, Bb, G#, F (two keys, one long, one short, that play the same note), and D#). While we occasionally make 8-key flutes with a 3-keyed footjoint (adding a C and C# key to the standard 6-key design), this option is still in the R&D phase of development as of this writing. Please let us know if you are interested in an 8-key model. The parts of the keys are identified as follows:

  • Pad: the soft leather-covered seal that attaches to the bottom of the cup and seals the hole as it rests against the pad seat. If the key is operating properly, no action is needed on the part of the player to ensure that the hole remains airtight—the action of the spring below the key will keep the key in the closed position and the hole sealed.

  • Key Shaft: the thin central section of the key. The shaft has a small metal pin running through a hole in the key and the key mount that keeps it in place.

  • Touch: usually roughly circular, the touch is the part of the key that the player’s finger depresses to raise the key, venting air out of the hole.

  • Pad Seat: the recessed area around the tone hole that is covered by a key.

  • Key Mount: the section of the original wood contiguous with the body that is left in place when the flute is turned, and into which the key slot is carved.

  • Bumpers: pieces of cork are shaped and glued to the bottom of the touch to cushion the action of the key.

  • Spring: a piece of curved brass that is pinned to the underside of the key shaft and which holds the key in the closed position, sealing the hole when the key is not in use.

  • Key Slot: a narrow groove that is cut into the key mount to allow the key shaft to be pinned in place.

  • Pin: a small silver pin that passes through the key shaft and the mount and holds the key in place.

A note on block-mounted vs. post-mounted keys: our keyed flutes are almost all block-mounted, meaning that the key is attached to a wooden mount that is carved out of the body of the flute as it is being turned. The mounts begin as thick, raised rings that are turned out of the wood when the flute body is roughed out; then the wood is removed except for a small section that will be left in place to form the mount. “Post-mounted” refers to a style of key-mount found on some antique flutes, most clarinets, and many other wind instruments in which the keys are attached to the body of the instrument with small metal posts.


The headjoint of each flute is sealed with a corked plug that is set to a precise depth to ensure that the headjoint will not leak air from the top and to achieve the best intonation possible. The distance from the plug to the mouth hole is one of the many variables that impact the tone and intonation of a flute.


Except for our all-wood models (which do not have tuning slides or metal rings), our flutes have sterling silver bands that wrap around the ends of the head and foot-joint, and in the case of the two-piece center section, the joint between the two. Our all-wood models have “rings” turned into the body of the wood in profile—for aesthetic purposes—while the silver rings also help to protect the body of the flute from scratches or other accidental damage.

Sections of a flute:

Our flutes are made in anywhere from three to five sections depending on the model or style, the biggest deciding factor being whether the instrument has a tuning slide. A tuning slide allows manual adjustments to be made to the pitch of the instrument, and

necessitates separating the headjoint into two pieces (headjoint and barrel) to allow the slide to be inserted into the head tube during construction.

  • Headjoint: the “top” of the flute. Houses the mouth-hole or embouchure. The top end is sealed with a small corked plug above the embouchure and capped with the end-cap. We make headjoints both with and without tuning slides, the tuning slide necessitating a two-piece head joint. Headjoints with tuning slides are available half-lined (also called “French style”) and fully lined. More information about half-lined vs. fully-lined headjoints can be found here.

  • Barrel: the small, lower section of the headjoint on flutes with tuning slides that allows the two sections of the headjoint to move freely via the slide.

  • Mid-section: The center section of the flute that houses the six finger holes. This can be made in either one or two pieces to suit the player’s preference (some prefer the holes all in a straight line, which does not necessitate a second piece, while some find it more comfortable to have the option to offset the right-hand and left-hand sections slightly.

  • Footjoint: the narrowest section, adjoins the mid-section at the “bottom” of the flute. Does not have finger holes but does sometimes have extra keys and/or the #7 and #8 tone holes.


The larger part of the connection to an adjacent section of a flute. The sockets on a headjoint, foot-joint, and two-piece midsection are drilled out to exactly fit the adjacent tenon, which fits inside the socket.


The part of a flute’s mid-section and footjoint that fits into the adjacent socket. Generally, we wrap the tenons of our flutes with carefully shaped cork to ensure a smooth, airtight seal. On some flutes and other wind instruments, the tenons are instead wrapped with thread.

Tone holes/Numbered holes

Typically, our keyless flutes have nine holes. The finger holes and holes that vent air on the foot-joint are called “tone holes,” and are numbered 1-8, beginning with the index finger nearest the head-joint. Put another way, the #1 hole corresponds to the left index finger of a right-handed player, and so on. Holes #1-#6 fall on the mid-section of the flute, while holes #7 and #8 fall on the footjoint. These numbers are also important in delineating the different models of flutes we make, since part of the difference between the Pratten, Nicholson, and Rudall & Rose models are the size of the holes.

Tuning Slide

A tuning slide is a two-part metal sleeve inside the headjoint that allows it to be made slightly longer or shorter, lowering or raising the pitch of the flute accordingly. This means that the headjoint is made in two pieces (headjoint and barrel). A tuning slide allows the player more freedom to adjust the pitch of the flute to match other instruments. We make flutes both with and without tuning slides. Those without are made with a one-piece all-wood headjoint.

Note: while the above terms are not universally applied, it is our hope that this glossary can help flute players, enthusiasts, and makers better understand these unique instruments. Questions? Email us here.

(Please note that all photos are ©2020 by Olwell Flutes)

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  • Patrick Olwell

I have long been intrigued by my own experience and other flute players’ reports that different types of wood have different sound qualities or feel different to play—an idea that seems to contradict things I have read about the physics of flute acoustics. Some acousticians have claimed that the type of wood the flute is made of is irrelevant to the sound that is created and that only the empty space inside the bore is actually creating sound. Why then do flutes made of different woods feel so different to play, even when the difference is less pronounced or indiscernible to someone listening?

I had the beginning of an idea while staring at a diagram of the inner ear on the wall at the doctor’s office, and thought that the place where the flute rests against the chin of the player is only a few inches from the components of the middle and inner ear. Sometime later, I read an article in National Geographic about the evolution of whales ears and the way that their hearing organs support their use of echolocation. The article included the following diagram. I was struck by the line “Sounds were transmitted to the middle ears of the Basilosurus as vibrations from the lower jaw (71).

The idea need not be confined to whales alone. Steven Connor writes, “Teeth seem to be involved in the transition from the touched sound of a pre-recording era and the untouched sound of a post-recording era. This is because teeth represent an alternative route into the ear, or even a way of short-circuiting the ear. It is said that the deaf Beethoven gripped between his teeth to convey the sounds of the piano to him. Similarly, Thomas Edison would champ on the wood of a gramophone in order to hear faint overtones that, as he claimed in a 1913 interview, were normally lost before they reached the inner ear…”

What if part of the “sound” that the player experiences is in fact created by the vibration of the flute against the jaw and teeth, which might transmit this vibration to the middle and inner ear as a proprioceptive experience of sound? If we assume that different kinds of wood vibrate differently, the idea of the jaw transmitting sound might help to explain the experience of the player—that somethings sounds or feels different, even when to the listener, these differences are slight or even imperceptible.

Regardless of whether these acoustic properties are measurable with the tools available to us today, it is interesting to suppose that the experience of the player is not necessarily purely subjective or imaginary, and that how a flute feels might be just as important as how it sounds.

-Patrick Olwell, Ed. Matthew Olwell

(Editor's note: we have read some claims that the wood of a flute does not actually vibrate, and that the vibration is present only in the air moving inside the instrument. To us, this idea is counterintuitive and at odds with the sensation of vibration we experience in our fingers when playing the flute. We recognize that more research may be needed to clarify this point,

and offer the ideas in this post in the spirit of inquiry.)

Works Cited

Chadwick, Douglas H. “Evolution of Whales,” National Geographic, November, 2001.

Connor, Steven. “Edison’s Teeth: Touching Hearing.” 2001.

Note: special thanks are due to Ivan Goff for introducing us to Steven Connor’s article, cited above.

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  • Patrick Olwell

Many discussions of the different types of simple-system flutes currently played in Irish music mention tone-hole size in comparing flutes, but the usefulness of terms like “small holes” or “medium holes” is limited without actual measurements. Hoping that it might prove useful to players and those interested in the similarities or differences between various flutes, here is some information about our in-house system of classification...

Right-Hand Tone Holes, Blackwod Pratten

We use the measurement of the #4 hole (which corresponds to the right hand index finger for a right-handed player) as the main reference point that describes the “size” of a flute—this corresponds with our Pratten, Nicholson, and Rudall-Rose models. The reason I started using the #4 hole is that I use the G and D scales to lay out the tonal “map” of the flute, and I use these triads in the first round of tuning each instrument as it is being made. (Note that we’re talking here about concert flutes in the key of D, but the same general rules and nomenclature apply to flutes in other keys.) I tend to think of the first octave G (and sometimes also the low D) as “home base” and G is usually the first note that I check using a tuner. Although somewhat a quirk of our making process, this system may also be related to the general layout of a six-holed transverse flute, as small D piccolos are called G flutes in China, and in India this note is also often the tonic. Another factor is the likelihood of a given note playing more true than another: the G-position note on simple-system flutes is often more dependable than the A, which tends to be unpredictable on 19th century London flutes as well as some others.

There is also the question of tone and feel. On simple-system flutes, the size of finger holes on one instrument relative to another affects the “voice” or character of tone that the flute will have. To my ear, a flute with smaller holes feels a bit more veiled, subdued, or not as “open” as one with larger holes (complicated by the fact that the bore and embouchure also have a significant impact on these qualities). This is important in choosing the sound and feel you prefer as a player.

Anyhow, in the interest of reducing the overall confusion regarding what constitutes small, medium, or large holes, here is our yardstick or classification system, which corresponds to our Pratten and Nicholson models etc...

#4 hole:

  • 6.0–6.4mm (Smallest) Baroque and early Classical and Romantic period flutes.

  • 7.0mm (Smaller) Romantic period flutes, smallest holes on Rudall-Rose.

  • 8.0mm (Small) London-based flutemakers manufactured many of their flutes like this, even after Nicholson’s revolution.

  • 9.0mm (Medium) Nicholson Flute. The third photo below shows a Rudall-Rose flute and a T. Prowse flute that have almost identically-sized holes. Prowse was authorized to stamp his “C. Nicholson’s Improved” and it’s my understanding these measurements represent the large-holed version of his flutes that other maker’s copied.

  • 9.6-10mm (Large) Pratten Flutes.

There are of course exceptions to the above specs if we are talking about antique flutes, and the water is muddied by the fact that many English flutes fall somewhere between the above delineations (what do we call a flute with a #4 hole of 7.5mm or 8.5?), but at least this is a standardized nomenclature that we can employ to compare one flute to another with some level of precision.

We use this system to describe our own flutes, and on our price list the 8.0 is referred to as Small, the 9.0 mm is Medium, and the 9.6 is Large (we realize that a Baroque musician might call the 6.0mm “normal’ and the 9.0mm “gigantic.”) We don’t currently make a flute with anything smaller than the 8.0 above, as most of our customers are playing traditional music and want the more “open” sound. I do own many antique flutes (including two by Rudall-Rose) with smaller holes that I think have a beautiful tone.

If you want to know the specific measurements of your own flute, you can buy a plastic vernier caliper (plastic is good because you won’t risk scratching the flute) for about $20. This comes in handy if you want to make precise measurements.

I hope that this system of sizing will aid anyone who wants to compare flutes and gain some insight into the way that hole-size effects tone.



(Pictured above: French, 6.5mm, American, 7.0mm, and Rudall-Rose and T. Prowse, 9.0mm)

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