If this specific sound isn't perfect, you can find similar audio at these sources:
I can give you more specific advice on editing or find the perfect audio to match! Countdown-Boom | Royalty-free Music - Pixabay Download countdown boom 76577 mp3
ElevenLabs Free Countdown Sound Effects : AI-generated options like chimes and ticks. If you can tell me: If this specific sound isn't perfect, you can
are you using this for (e.g., YouTube video, presentation)? Do you need other sound effects to go with it? If this specific sound isn't perfect