Soundproofing between units?

[Stuart Alexander]

Hey everyone, currently living in a house-hack (over/under - we live in the upper unit). Original plan was to move on after a year, but we really like the area.

Problem is, it's a wood frame construction, and the noise transfer between the units is starting to bug me. Louder conversations can be heard as muffled speech, I often use the heat pump to drown it out. Social visits from either unit will cause a decent amount of sound to enter the other unit.

Considering living here longer, but we might address the sound issues. Does any one have any experience with this?

Hoping to mostly resolve speech/ect noises not impact as I know that is a different beast.

Planning on keeping the existing ceiling, but adding
-sonopan
-resilient channel
-5/8th dry wall

Would this make a noticeable difference? It will be a decent chunk of money.

Is it possible to just do the living spaces (living room, kitchen, hall way) and leave the bedrooms unchanged?

Thanks in advance!