If this specific sound isn't perfect, you can find similar audio at these sources:
For maximum impact, layer this sound effect with a low-frequency rumble or a slight crescendo (gradual increase in volume) during the countdown numbers leading up to the boom. Download countdown boom 76577 mp3
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, you can
I can give you more specific advice on editing or find the perfect audio to match! Countdown-Boom | Royalty-free Music - Pixabay If this specific sound isn't perfect
Match the "boom" exactly with the final digit (zero) or the visual explosion/change in your media.
Mixkit Countdown Sound Effects : Various styles, including clock bleeps and voices.