Morse code in music: playing messages as rhythm
To play Morse code as music, make each dit one short note, each dah a note three times as long, and turn the silences into rests: one unit between the parts of a letter, three between letters and seven between words. If an eighth note is your unit, a dah is a dotted quarter note, a letter gap is a dotted quarter rest, and a word gap is seven eighths of rest. Keep those proportions and anyone who reads Morse by ear can read your rhythm.
Morse is already rhythm. Operators learn letters as sounds, not as dots on paper, and A is heard as di-dah long before anyone thinks “dot, dash”. Writing it in note values just makes that rhythm exact.
Morse in note values
Morse timing is built on one unit, the length of a dit. Choose a note value for the unit and everything else follows:
| Morse part | Units | Unit = eighth note | Unit = sixteenth note |
|---|---|---|---|
| Dit | 1 | Eighth note | Sixteenth note |
| Dah | 3 | Dotted quarter note | Dotted eighth note |
| Gap inside a letter | 1 | Eighth rest | Sixteenth rest |
| Gap between letters | 3 | Dotted quarter rest | Dotted eighth rest |
| Gap between words | 7 | Dotted half rest plus an eighth rest | Dotted quarter rest plus a sixteenth rest |
Two things are easy to get wrong. First, play each note for its full value. A staccato dah, cut short, sounds like a dit, and the whole letter changes. Second, the rests are not decoration: they tell the listener where one letter ends and the next begins. The 1, 3, 7 rule explains why the gaps carry as much meaning as the sounds.
A counting trick: each note owns its rest
Writing every rest separately gets fiddly. It is easier to give each element the one-unit rest that follows it, then add a little extra at the end of a letter or a word:
- A dit and its rest: 2 units.
- A dah and its rest: 4 units.
- At the end of a letter, add 2 more units, making the 3-unit letter gap.
- At the end of a word, add 6 more instead, making the 7-unit word gap.
With an eighth note as the unit, those come out in whole beats of 4/4: a dit is one beat, a dah is two, the end of a letter adds one beat and the end of a word adds three. So A, .-, plus its letter gap is one beat, two beats, one beat: exactly one bar. N, -., also fills one bar, in the opposite order. E plus its letter gap is two beats; T is three.
Turning a word into a beat
A step sequencer with 16 steps to the bar, one step per sixteenth note, is a good place to build Morse, because each step is one unit. Here is the word MORSE, one letter per line, where X is a step with the sound on and _ is a silent step. Each line includes the gap that follows the letter:
M XXX_XXX___ 10 steps
O XXX_XXX_XXX___ 14 steps
R X_XXX_X___ 10 steps
S X_X_X___ 8 steps
E X_______ 8 steps
50 steps
The rhythm words say the same thing: MORSE is dah-dah, dah-dah-dah, di-dah-dit, di-di-dit, dit. In Morse it is -- --- .-. ... ..
The word happens to be 50 units long, the same as PARIS, the standard word for measuring speed (what WPM means shows that count). But 50 steps is three bars and two steps, so a looped MORSE drifts against the bar line. Two ways to handle that:
- Let it drift. The word lands somewhere new each time round, which can sound good against a steady beat.
- Pad the final silence. Stretch the word gap from 7 steps to 21, so the word fills exactly four bars. The letters keep their shape; there is just a longer pause before the word comes back. Farnsworth spacing does something similar for learners, stretching the gaps while every character keeps its speed.
Padding the gaps between letters would also fit the bar, but keep them equal and clearly shorter than the word gap, or a long letter gap starts to sound like the end of a word.
Tempo and words per minute
Morse speed is measured in words per minute, and a dit lasts 1200 divided by the WPM, in milliseconds. A sixteenth note at a tempo of T beats per minute lasts 15000 divided by T milliseconds. Put the two together and a few useful pairs fall out:
| Tempo | Unit | Unit length | Morse speed |
|---|---|---|---|
| 100 BPM | Eighth note | 300 ms | 4 WPM |
| 100 BPM | Sixteenth note | 150 ms | 8 WPM |
| 120 BPM | Sixteenth note | 125 ms | 9.6 WPM |
| 150 BPM | Sixteenth note | 100 ms | 12 WPM |
| 125 BPM | Thirty-second note | 60 ms | 20 WPM |
With sixteenth notes as the unit, the WPM is the tempo divided by 12.5. Morse at 20 WPM is thirty-second notes at 125 BPM: quick, but still a rhythm you can hear. Slower songs make slower Morse, and the code stays readable at any tempo as long as the proportions hold.
Making it sound like Morse
The timing is the message, so anything that blurs the timing blurs the message.
- Use a sound that holds. Morse is a steady tone, on or off. A sustained sound, like a plain synth tone or an organ, shows the difference between a dit and a dah. A drum hit dies away almost at once, so a dah played on a drum sounds like a dit.
- On drums, use two sounds. If you want Morse on percussion, give dits one sound and dahs another, as people do when they tap Morse on a table. That is a translation rather than true Morse timing, so say so if you want listeners to decode it.
- Keep the tails short. A long release or a lot of reverb fills the rests, and a one-unit gap disappears. Give the Morse part a short release and keep the effects dry.
- Turn off swing on the Morse part. Swing lengthens every other note, so dits and gaps that should be equal no longer are. Quantize the part straight, even if the rest of the track swings.
- Keep one pitch, or change pitch with care. A single pitch sounds most like Morse. Melody is possible, with dits and dahs on different notes, but the timing must stay exact, because a listener decodes by length, not by pitch.
- Give it room. A Morse line buried under a busy drum part is hard to follow. Pick a sound and a pitch that sit clear of the other instruments.
Recorded Morse may use Farnsworth spacing, with longer gaps between letters and words than the 3 and 7 units on your grid. If you line up a recording against a beat, match the characters first and then set the gaps yourself. Farnsworth spacing explained shows what it changes.
Hearing it before you program it
Say a word’s rhythm aloud before you build it: di-dah, dah-di-di-dit. Your voice catches a wrong letter faster than your eye does on a grid. On a Mac, Dot & Dash can help with the code itself: its Text to Morse turns any phrase into dots and dashes ready to copy, and Play sends it on its on-screen machine, so you hear the rhythm while the paper tape prints it. It can also share a message as an .m4a audio file, the tone along with the machine’s own sounds, to use as a sample; how to make a Morse code audio file has more on audio files.
Questions
How do you write Morse code as music notes?
Pick a note value for one unit, such as an eighth note. A dit is one eighth note, a dah a dotted quarter note, and the gaps are rests of one eighth inside a letter, a dotted quarter between letters and seven eighths between words.
What tempo matches Morse at 20 WPM?
A dit at 20 WPM lasts 60 milliseconds, which is a thirty-second note at 125 BPM, or a sixteenth note at 250 BPM. With sixteenth notes as the unit, the speed in WPM is the tempo divided by 12.5.
Can you play Morse code on drums?
Not in true Morse timing, because a drum hit cannot be held long enough to make a dah sound different from a dit. Give dits and dahs two different drum sounds instead, and keep the gaps between letters and words clear.
Why does my Morse rhythm sound wrong?
The usual causes are notes cut short, which turn dahs into dits, reverb or a long release filling the gaps, and swing, which makes equal notes unequal. Play full note values, keep the part dry and quantize it straight.