Interior walls sound - door gap

[Mainstream]

I made the same journey. Ended up choosing regular solid doors with sealing strips in the frame from here:
http://www.mindorr.se/karm/vit-kvistfri-karm-inkl-monterad-tatninglist
I also considered sound-rated doors, but they feel a bit too much like exterior doors to me.

The threshold for the rooms we want extra quiet seals tightly. In the other rooms, it's a regular smooth threshold.

The problem is ventilation. For the supply air to work, you need either a gap under the door or an air transfer grille. Or as we have done, an exhaust vent. You want the ventilation to work with the door closed!

 

[Ulf1]

You really have to be meticulous if it's going to work as intended.

Excerpt from SP:
"It is of great importance that all connections between partition constructions are completely sealed. A gap that is a millimeter wide can let through so much sound that the apartment-separating construction loses most of its sound-insulating ability."

Building a simple plaster wall without gaps is more or less impossible... It will probably take a lot of sealant and time...