Once I install the RSIC-1 do I need to do anything else to help the noise isolation?

 Yes. The RSIC clips greatly enhance the performance of the insulation. When you just add insulation to a wall or ceiling without RSIC clips there is little change in the acoustical performance of the system. However when the total decoupling (isolation) of the gypsum board from the structure is accomplished with the RSIC-1, the insulation becomes a very important part of the noise control assembly. 

There are several types of rc channel, not all of them work the same. It is also possible that the installer has short circuited the gypsum board to the framing members by using a screw that is too long.

There are many different types of RSIC clips on the web site, how do I know which is the correct one to use on my project?

STC (Sound Transmission Class)

IIC (Impact Insulation Class)

What is the difference between the lab STC's and IIC's versus the Field STC's and IIC's?

Why can I hear my neighbors walking above me, I was told that I wouldn't be able to hear them once the RC channel was installed?