[Hikmer]

Recently had my home re-piped and have an opportunity to stuff the cavity between my ceiling and second floor with rockwool safe and sound.  I have Vandersteen 5a (dual subwoofer) and always looking to control bass (already have a few bass traps).  Does anyone have experience in adding rockwool behind drywall, is it worth the effort?  This would be between my ceiling and second floor.  I'm guessing it couldn't hurt, I have a very long room and olny half the room would be treated at this point.  But I figure something is better than nothing.  Thoughts?

[mcgsxr]

I did my whole basement cavities with Roxul - ceiling bays, interior walls etc.

Some will help, but sound will travel around and through for sure.

I’d still do it (you won’t likely have access ever again), but don5 expect perfection of prevention. 

[Hikmer]

I'm not concerned about sound travelling through, just controlling bass frequencies.  Question, do you fill the whole cavity or just adding some material is good enough?  The space is 9 in tall, their documentation suggests I fill 6 in edge to edge.

[cementhead]

Like mcgsxr, I did my whole room with the Roxul while renovating. Also, did the room with 5/8 Sheetrock instead of 1/2 ".  Did it make a difference? Maybe, but while it was open, it was the time to do it!

[Hikmer]

Thanks, Rockwool purchased.