Is a duct liner enough for insulation/absorption.
Ted White strongly emphasizes a significant amount of insulation for a high level of absorption. Do you recommend only Duct Liner for the baffle box kind of dead vent.
Uscmatt99 writes that the main thing is mass. And insulation helps also a little.
I think if a Flax Duct Pipe even wrapped with insulation decreases the amount of absorbing because the sound energy will slide trough the wall of the pipe. And a fewer amount of sound will be absorbed in the underlayment insulation. May be thats why they claim all the time that insulation helps only a little bit.
However i don't want the walls to be covered by exposed insulation. Since we need clean air.
One way is to lay on top of the insulation acoustic foam.
Another way is to use thick acoustic foam only and with the damped mass it will be enough for a high STC.
The thing is, i dont find any stc data on that kind of baffle box, which one tells that they can't hear nothing through the Vent
So do you have some proof that Duct Liner is enough
I work so long to make the room air tight so im looking for a high STC dead vent
Here is a data sheet of a kind of liner http://www.owenscorning.com/around/sound/commercial_acoustics/FIBERGLA.PDF
Im very concerned about the health issues here.
Anyway i find another company
So what do you say to this kind of liner
Claims to be healthy and noice reduction.
I think if acoustical foam is healthy to lay in a ventilation system.
Look to what value they need to assure
• Resists fungi, mold, mildew, bacteria growth, mild dust, dirt and humidity
Air is what we breath. And needs to be healthy.
I think that Roxul insulation is not a problem as long it's covered with drywall or alike.