How Does A Recorder Work?

When learning a new instrument, it’s best that you know how it works to play at the best of your ability.

Today we’re tackling the recorder and, fortunately, it’s a relatively simple instrument that won’t take too long to explain. By knowing what goes on inside of your recorder, it becomes easier to learn how to play.

In fact, the recorder is the simplest and easiest to learn of all the woodwind family, making it a favorite for young learners and a great foundation for developing techniques that can be used on more advanced woodwind instruments.

How Does A Recorder Work

The Basics

Recorders create sound in a way that’s similar to a whistle, with the player directing their breath into the instrument’s windway. This starts at the head joint, where the iconic narrow channel of the recorder receives bursts of air. 

As the air is pushed through its interior, it hits a sharpened edge that’s called a labium. This effectively splits the air stream, with some surging below the labium and some arcing over it to produce sound.

This causes an oscillation down the length of the recorder’s bore, which in turn vibrates the air column to create resonance and, ultimately, sound.

By just blowing into a recorder, a player establishes and maintains a single pitch of the recorder’s sound that is often called the fundamental.

Overtone

The main function in all woodwind instruments is the air column inside them, which has different types of vibration that are generally referred to in the music industry as overtone. This is the study and analysis of standing waves that form inside the instrument when it is being played.

Upon hearing waves, you may be tempted to think about sound waves or radio waves, but standing waves act differently. First, they’re stationary, because they’re based more on pressure differentials in an object than a wave that travels once it’s formed.

These pressure points are referred to as nodes and the lowest and loudest vibrations are responsible for the lowest possible pitch a recorder can make in the air column.

All other pitches are the overtones, also called harmonics. These pitches are described by how many identifiable pressure nodes are created in the air column to produce the sound.

This is where terms like register come in, with the first register corresponding to one single node while the second register makes use of two nodes, and so on until you hit the upper register.

It's worth noting that as the number of nodes in your recorder increases, the player has fewer notes to work with since bore’s node spacing can’t facilitate any more notes while the extra vibration is going on.

Register

Let’s go into more detail about what each register means and how your fingers will interact with the tone holes to produce different notes.

So far, we’ve only talked about the basic means by which a recorder creates sound but players need to channel that airflow to create a variety of desired sounds that can be pleasing to the ear.

Note that we’ll be going through the note names you can expect when playing on an alto recorder, so some note names may be different on your instrument if you don’t have an alto or treble model.

First, let’s look at the several notes that are possible on the first register:

  • Low f – The low f note is your recorder’s air column at its absolute longest. This is achieved by blocking every tone hole, thereby producing the lowest sound that the recorder is capable of. Higher notes are made by shortening the air column inside the instrument by covering some or a combination of these holes.
  • Low a – The low a note is played by keeping the thumb and finger holes covered while turning the foot joint so that the last tone hole is obscured.
  • Low b – Low b is achieved by fork fingering, otherwise called cross fingering, which is used to play semitones instead of the set tones that a recorder can play. To fork finger and achieve a low b, you keep everything covered while blocking the foot joint hole again. Keeping the holes around it covered, you then free the fourth bore hole to create the desired noise.
  • Low d – To play a low d note, you only keep the thumb hole and the first two finger holes covered. The four other holes are left open to keep the air column short to produce the d sound.
  • Middle g – Middle g is another fork fingering method where only one hole is covered to create the desired sound. This time it’s the second finger hole in, on top of your recorder. A good way to find this is to make the low d sound and then keep the hole furthest from you covered while freeing everything else.

Then we get into higher registers, where there is more than one pressure node existing within the air column. This is done by restricting the typical first register airflow so that the air is forced to divide into two parts. The way we do this on the recorder is by partially covering the thumb hole so that it leaks air.

Making a middle a in the second register is done by leaking the thumb hole while covering every finger hole except for the one at the foot joint. 

Logically following from how we created the second register, the third register is reached by introducing another air leak so that there are three competing velocity nodes inside the instrument that create higher notes. 

By keeping the thumb leak and the uncovered foot joint hole, but also uncovering the central hole of the five finger holes, you can create a high e, for example.

Once again, introducing yet another leak on top of the recorder will break the third register and enter the fourth.

To play a high g, this is done by partially closing the thumb hole, fully covering the first finger hole, leaving the second uncovered, covering the third and fourth, then uncovering the fifth. 

Cover the two holes after the fifth, and you’ve now created four pressure nodes within the recorder’s air column that can play high notes.