On 19 Apr 2007 10:50:04 -0700, wrote:

Long story short, I have only a few days to get these answers and do
the work. I'm having my basement finished and I'd like to lessen the
sound transferring
1) through the HVAC ducts
2) From the floor above through to the basement (vinyl and wood floor
above)
3) From a PVC drain pipe
4) From a room with all my mechanicals (heater etc) to the finished
area

I know I've seen a very dense foam that could be installed between the
joists but I haven't been able to find it. Any other suggestions. I
live in SE MI if that matters. Thanks.


Forced air and soundproofing are very nearly mutually exclusive.
And starting to figure out what you're doing "a few days" before you
have to be finished guarantees either a bad job, or a missed deadline.


If you're trying to reduce sound FROM the air ducts, make them bigger.
If you're trying to reduce sound THROUGH the ducts from one room to
another, make them smaller, and do independant runs and returns
to the furnace for each section.

In all cases add as much weight to assorted sound-transfer surfaces as
you can. Decouple the surfaces where sound is generated from
surfaces where you don't want sound tranmitted.