You can try like this. You practice in a quiet place; also try to practice in a very noisy place. If you can meditate in a noisy place – when the mind has no problems anymore – you have already solved the problem.
If you can meditate, it means that the mind is already calm. If it’s calm, it means that you can sleep anywhere.
If you can meditate any place – quiet place or noisy place – the mind has understood about the sound (it’s an object) and doesn’t react. Then, this person can sleep anywhere.
| Taiwan Retreat 2018 Q&A 7 (33:04-33:42)