What pitch should Morse code be? Choosing a sidetone
There is no official pitch for Morse code. The code lives in its timing, not its tone, so any pitch carries it equally well. Many operators settle somewhere between about 500 and 800 Hz, and 600 Hz is a common default. Choose the pitch you can listen to for half an hour without tiring, and if you plan to operate on the air, set your practice tone close to the pitch you will tune signals to on your radio.
That is the short answer. The rest of this post is how to find your number, and why you might move it later.
Why Morse has no fixed pitch
On the radio, Morse is sent as CW, continuous wave: the transmitter switches a plain carrier on and off. There is no audio tone in the signal at all. Your receiver makes the tone you hear by mixing the incoming carrier with a signal of its own, and the pitch depends on the difference between the two. Tune slightly one way and the same station’s dits rise in pitch; tune the other way and they fall.
So the sender does not choose the pitch you hear. You choose it, with your tuning. Two people listening to the same station can hear it at different pitches and copy exactly the same text.
The sidetone is the tone you hear while you send: the oscillator in a keyer, a transceiver or a practice set that sounds whenever your key is closed. It exists only for you, so its pitch is a matter of comfort. The ITU standard that fixes the 1, 3 and 7 unit timing of Morse does not set a pitch.
Common pitches and how they tend to feel
Pitch is personal, but the range people use is fairly narrow, and each part of it has a character:
| Pitch | How it tends to sound |
|---|---|
| 400 Hz and below | Deep and soft; restful, but short dits can sound dull |
| 500 to 600 Hz | Warm and clear; a comfortable choice for long sessions |
| 700 to 800 Hz | Brighter and crisper; dits stand out at higher speeds |
| 900 to 1000 Hz | Sharp; it cuts through, but can grow tiring over a long session |
Two things matter more than the exact number.
Volume. A sidetone that is too loud wears you out at any pitch. Set it so you hear every element clearly but would still notice someone speaking to you. With headphones, start quieter than feels natural; you can always turn it up.
The shape of the tone. A clean sidetone is a sine wave that rises and falls over a few milliseconds at the start and end of each element. A tone that switches on and off instantly clicks at every edge, and a buzzy waveform adds harsh overtones. Both get tiring over a long session. A clean tone at 700 Hz is kinder than a harsh one at 500 Hz.
Your ears are not someone else’s ears
Hearing differs from person to person and can change over the years, so the pitch that suited you once may not suit you now. If high tones sound thin or distant to you, a lower sidetone may simply be clearer. If you live with ringing in your ears, try a wider spread of pitches in the test below and keep the one you hear most clearly. This is about comfort, not a hearing check; if your hearing worries you, talk to a professional.
The only test that counts is your own. A five-minute way to find your pitch:
- Start at 600 Hz at a moderate volume, and listen to a minute of Morse at the speed you practice.
- Step down to 500 Hz, then up to 700 and 800 Hz, a minute at each.
- Note which pitch lets you hear each dit as a distinct sound without effort, and which you would still enjoy after twenty minutes.
- If those are two different pitches, take the lower one. Then leave it alone for a couple of weeks, so you are learning rather than fiddling.
Fold the test into your normal session rather than adding a separate one; a 10-minute daily practice routine has room for it.
Pitch and speed
At learning speeds pitch hardly matters. As you speed up, dits get short enough that the number of cycles of tone in each one starts to show. A dit lasts 1200 divided by the WPM, in milliseconds, so:
| Pitch | Cycles in a dit at 12 WPM (100 ms) | At 20 WPM (60 ms) | At 40 WPM (30 ms) |
|---|---|---|---|
| 400 Hz | 40 | 24 | 12 |
| 600 Hz | 60 | 36 | 18 |
| 800 Hz | 80 | 48 | 24 |
| 1000 Hz | 100 | 60 | 30 |
A dit of a dozen cycles, with its edges softened, can sound more like a soft knock than a note. If your dits start to blur as you push past 25 or 30 WPM, try raising the pitch by 100 Hz before you blame your ears. Treat it as an experiment, not a rule: plenty of fast operators never move their pitch at all.
Pitch does not change timing. A dah is three dits long at 400 Hz and at 1000 Hz, and the gaps do not change either. If your copy improves when you change pitch, the sound got clearer; the code did not get slower. The arithmetic behind the table is in How long is a dit? Working out Morse timing from WPM.
Matching the pitch you will hear on the air
If you practice for fun, or use Morse away from radio, pick the pitch you like and stop there. If you plan to operate CW, there is a good reason to line your practice tone up with your radio.
On many transceivers, one CW pitch setting controls both the sidetone and the pitch at which a correctly tuned station is heard; your radio’s manual says whether yours works that way. On such a radio, when an incoming signal sounds at the same pitch as your sidetone, you are tuned close to the other station’s frequency, which is where they expect your reply. Operators often tune by ear this way, sweeping until the signal matches the tone they know.
If you spend months practicing at 600 Hz, that pitch becomes the one your ear expects. Setting your radio to the same number makes your first real signals sound familiar, and makes tuning by ear easier, because the pitch you are matching is one you already know well.
Do not tie yourself to a single pitch, though. On the air, several stations can be in your receiver at once, each at its own pitch, and part of copying is following one tone while ignoring the rest. Once your copy is steady, spend the odd session a couple of hundred hertz above or below your usual pitch. The letters should sound like the same letters. If they do not, you are leaning on the tone rather than the rhythm. What CW is: Morse code on ham radio explained covers what else changes when the signals are real.
Setting the pitch on a Mac
macOS has no Morse sidetone of its own, so your pitch depends on whatever makes your practice tone: a keyer, a practice oscillator, a set of audio files or an app. Recorded practice files fix the pitch at whatever their maker chose, which is one reason to generate your own audio or use something you can adjust.
In Dot & Dash, the sound controls are in Settings, General: a Pitch setting from 400 to 1000 Hz, 600 Hz by default, with Volume and Mute. Run the five-minute test above with it, then leave the pitch where your ears are happiest.
Questions
What is the standard pitch for Morse code?
There is none. The international standard defines the timing of dits, dahs and gaps, not the tone. 600 Hz is a common default, and many operators settle between about 500 and 800 Hz.
Does a higher pitch make Morse easier to copy?
Not in general. At high speeds a slightly higher pitch can make very short dits sound crisper, but at learning speeds the best pitch is the one you find clearest and least tiring.
Should my practice pitch match my radio?
It helps if you plan to operate CW. On many transceivers the sidetone and the pitch of a correctly tuned station are the same setting, so practicing at that pitch makes real signals sound familiar.
Can I learn Morse at one pitch and copy it at another?
Yes. The code is in the rhythm, so every letter keeps its shape at any pitch. Practicing at a few different pitches once you are comfortable makes the switch easier.