The wall between my main bedroom and the adjacent bedroom of my neighbour's house doesn't block sound at all well. I was glad when my previous neighbours left as they had a fondness for dance music in the middle of the night, but the new lot turned up for a look today and I could hear an excited child claiming that bedroom. That's going to be a problem.
So I'm thinking about sound insulation on the interior of the wall of my bedroom, but everything I've looked at is either designed specifically to stop outgoing noise rather than incoming noise or is just a thin piece of foam that doesn't look like it will have any significant effect.
Other than pooing through their letterbox, does anyone have any useful advice? I'll bear the letterbox approach in mind but not as a first step
For years, I had a neighbour who used that room only for storage. I didn't realise how valuable that was until they left.
So I'm thinking about sound insulation on the interior of the wall of my bedroom, but everything I've looked at is either designed specifically to stop outgoing noise rather than incoming noise or is just a thin piece of foam that doesn't look like it will have any significant effect.
Other than pooing through their letterbox, does anyone have any useful advice? I'll bear the letterbox approach in mind but not as a first step

For years, I had a neighbour who used that room only for storage. I didn't realise how valuable that was until they left.