How to Generate Morse Code Beeps in Audacity

This guide explains how to create clean, synthetic Morse code beeps in Audacity using the built-in Tone Generator. By calculating standard Morse code timing units and configuring the software's frequency and silence tools, you can assemble precise dits, dahs, and character pauses for any message without needing external plugins.

1. Understand Morse Code Timing

Standard Morse code timing relies on a base time unit called a "dit" (or dot). All other elements are derived from this single duration:

• Dit (Dot): 1 unit
• Dah (Dash): 3 units
• Intra-character space (between dits/dahs within a letter): 1 unit of silence
• Inter-character space (between letters): 3 units of silence
• Word space (between words): 7 units of silence

To calculate the unit duration based on Words Per Minute (WPM), use the standard formula: \[\text{Unit Duration (seconds)} = \frac{1.2}{\text{WPM}}\]

For example, at 20 WPM, one unit equals 0.06 seconds (60 milliseconds). A dah is 0.18 seconds, an intra-character gap is 0.06 seconds, a letter gap is 0.18 seconds, and a word gap is 0.42 seconds.

2. Configure the Tone Parameters

Morse code audio is traditionally a pure sine wave between 600 Hz and 800 Hz.

1. Open Audacity and create a new project.
2. Go to Tracks > Add New > Mono Track.
3. Select Generate > Tone... from the top menu.
4. Set the parameters:
   • Waveform: Sine
   • Frequency (Hz): 700 (standard pitch)
   • Amplitude: 0.8 (prevents digital clipping)

3. Generate the Base Elements

Create the standard building blocks on separate sections or tracks so you can copy and paste them:

1. Generate a Dit:

   • Go to Generate > Tone...
   • Set the Duration to 00 h 00 m 00.060 s.
   • Click Generate.

2. Generate a Dah:

   • Move the playhead forward or create a new track.
   • Go to Generate > Tone...
   • Set the Duration to 00 h 00 m 00.180 s.
   • Click Generate.

3. Generate Gaps:

   • Go to Generate > Silence...
   • Set durations for intra-element gaps (0.060 s), letter gaps (0.180 s), and word gaps (0.420 s) as needed.

4. Eliminate Audio Clicks (Key Click Reduction)

Abrupt starts and stops of pure sine waves create harsh clicking sounds known as "key clicks." To make the tone sound realistic:

1. Zoom in closely to the beginning of your generated tone.
2. Select the first 2 to 5 milliseconds of the wave.
3. Go to Effect > Fading > Fade In.
4. Select the last 2 to 5 milliseconds of the wave.
5. Go to Effect > Fading > Fade Out.

Apply this micro-fade to your master dit and dah templates before duplicating them.

5. Assemble Your Message

1. Select your processed dit or dah segment.
2. Copy it using Ctrl + C (Windows) or Cmd + C (Mac).
3. Place your cursor on the timeline and paste (Ctrl + V / Cmd + V).
4. Insert standard silence lengths between tones using Generate > Silence... or by copying pre-made silence intervals.
5. Repeat the process to spell out your text following the standard dot-dash patterns.

6. Export the Audio

Once your sequence is complete:

1. Click File > Export Audio...
2. Choose your preferred format (such as WAV for uncompressed audio or MP3 for smaller file size).
3. Set the sample rate to 44100 Hz and click Export.