Episode 1: 440Hz
440Hz and two overtones

Notes

Generated from:

generate_sine_tones() {
    local base_freq=$1
    local duration=$2
    local output_path=${3:-output.mp3}
    local overtone1=$(( base_freq * 2 ))
    local overtone2=$(( base_freq * 3 ))

    ffmpeg -f lavfi -i "sine=frequency=$base_freq:duration=$duration" \
           -f lavfi -i "sine=frequency=$overtone1:duration=$duration" \
           -f lavfi -i "sine=frequency=$overtone2:duration=$duration" \
           -filter_complex "amix=inputs=3:duration=longest" \
           -c:a libmp3lame -b:a 64k "$output_path"
}

generate_sine_tones 440 5 assets/audio/episode1-440.mp3