Old building - Resilient channel/sounfproofing questions

[Jerry N.]

We are doing a project in an old (typical Chicago) 1890s MF building.  Upper apartments will have finished hardwood floors.  Pre-reno sound transmission through the floors was really bad and we are looking to improve soundproofing, keeping the wood floors.

Does resilient channel really work? Enough to justify the cost - $1-2/sq ft?

Who installs it typically, the drywaller or carpenter?

Has anyone used it or just insulated enough where you thought it made a difference? 

Any recommendations or insights appreciated.

Thanks for reading.