[gremmy]

In an effort to quiet down the air-flow through the return and supply vents in my home theater, I decided to try an experiment by stuffing a small amount of linacoustic into each of the ducts.


A very generous forum member sent me a nice-sized sheet of linacoustic that he had left over from his theater build, and it was this sheet that I used for my duct muffling experiment.


The results? Well, they're mixed.

First, the good: with just a small amount of linacoustic placed around the bend in each of the ducts, the sound transmission through the vents dropped dramatically. So yes, as a duct muffler, this stuff works fantastically. Of course, the duct muffling characteristics should come as no surprise (since that's what the stuff is made for), but I was still surprised by how much noise reduction I was able to achieve with such small pieces of the stuff.


I had a nice sized sheet to work with, but I could only fit tiny pieces (maybe 1 foot long by 8 inches wide) into the duct without unduly restricting the air flow. And even those small pieces did the trick.


Before I inserted the linacoustic, my return air vent sounded like a friggin' jet engine. Afterwards, it was an ever-so-subtle whisper.

Now, the bad:

I think I'm allergic to the stuff. Immediately after placing it into my supply vent, I started getting all stuffy-nosed, coughing, watery eyes, etc. At first, I thought maybe my sinuses were irritated from working with it, so I waited a couple of days, but no luck. Every time I walk into the theater I am struck with a very stuffy feeling and a thick, unpleasant quality of air. I checked to make sure that the backing is installed facing the air-flow (so tiny particles of the stuff don't blow around the room), and found that it is, indeed, installed in the right direction.


Unfortunately, this linacoustic stuff isn't really meant to be installed like this at all. It's supposed to have its edges sealed (I don't know all the details, but I did read a bit about it), so maybe it's not possible for me to install this stuff the right way.


Anyway, I have just removed the linacoustic from the supply vent and will wait to see if that clears up the allergic reaction. If that doesn't work, it will have to come out of the return duct too. I thought about wrapping the linacoustic in GOM before stuffing it into the vent, but I think that would be destined to turn into a Dust Mite factory.


Summary:


So anyway, the linacoustic does successfully muffle vent noise. In fact, it works great -- a small amount goes a long way. Unfortunately, due to my allergic reaction to the stuff, I may not be able to use it.

 

[krasmuzik]

Gee - that must be why it is actually sold as duct liner rather than acoustical wall/panel material.....


bad thing about the fiber dust. Prior house had the liners installed backwards so ditto on the nose.

 

[gremmy]



Quote:
Originally Posted by krasmuzik /forum/post/12964571


Gee - that must be why it is actually sold as duct liner rather than acoustical wall/panel material.....

Exactlly. Although I must admit, even though I knew the stuff's intended purpose, I was still surprised at how little of the material it took to make a difference.

 

[BIGmouthinDC]

If you go to the Mfgrs web site and pull up the installation directions they make reference to a paint on edge sealant. I imagine that the edge sealant and the coating on one side are to manage the floaters.


So a few thoughts.


1) The process of doing all the work in the vents may have stirred up dust that was in the vents to begin with and your reaction was to that dust not the fiberglass OR


2) You are in fact allergic to fiberglass floaters. You could try sealing all the exposed edges with some duct tape and give it a try.


3) You could get some one inch COTTON insulation and place in the duct pretty much like you did the linacoustic. It won't be coated, it will get dusty and hold odors, it won't be code, but might reduce the jet engine sound. See Bpape (sensible sound solutions) for source.

 

[ifeliciano]

Interesting you're allergic. All my vents at the house have a built-in layer of a linacoustic like (duct liner) material. The material is placed with the "hard" part in contact with the air flow.


Try searching NAIMA ( http://www.naima.org/ ) for some tips on using the linacoustic.

 

[aham23]



Quote:
Originally Posted by ifeliciano /forum/post/12965647


Interesting you're allergic. All my vents at the house have a built-in layer of a linacoustic like (duct liner) material. The material is placed with the "hard" part in contact with the air flow.


Try searching NAIMA ( http://www.naima.org/ ) for some tips on using the linacoustic.

is that at the register (vents). if so, how much is being put into the register and does it really help prevent the sound from leaking into the room at that point?


thanks.

 

[gremmy]

Thanks for all the replies, everyone. As a temporary test, I decided to wrap the linacoustic in GOM and stick in back up there. So far so good -- the allergic type reaction is gone. I realize that over time dust is going to collect in the GOM, which could create its own sort of misery. So I'm playing this one by ear (no pun intended).