Acoustic insulation - which appointment covers this?

Sorry if this question has been answered elsewhere in the forum.
We would like to ensure the noise from our theatre room doesn't bother anyone (including us!) as our boys like to have their music pretty loud. We are unsure which appointment this is covered in, electrical maybe? We have only just started with our selections, we have chosen outside colours, carpets and tiles with the kitchen appointment next week. Its all a little bit overwhelming and Masterton is still on their break at the moment so I can't ask.
Does anyone know?

Totally different builder to you, but we asked for it as part of the original tender.
It doesn't really classify into the area of any of the seperate "selections" appointments we had. When would you usually ask for things like moving walls or rearranging windows; if you have a particular admin contact who's coordinating your file, they're probably the ones to directly ask how much this'd cost (they'd have to go through the estimators so the sooner you ask the better IMHO).

We picked our theatre room insulation on our colour selection day at masterton hope this helps

We did ours at tender stage as we wanted to know most things up front. I'm sure if you haven't had colours yet you can add at that time too