Plastic Thickness for Bass Traps

[jazzclub]

How thick should the plastic film be when trying to combat mids/high freq. absorption? Ive read and read for weeks, and everyone says "thin plastic".

What equates to thin... 1mm, 2mm, 3mm.

Or, what about the Kraft paper thickness, there are several different weights of them. I know brown paper bag thickness, but actually what thickness or weight.


I went to menards, and there is just to many to make an educated guess [I got none in this department]

[raticusfortuna]

using plastic on absorbers or traps is a DIY tweak. it's not the sort of thing acousticians test since they'd do it the right way to begin with. my thinking is if you ask someone whose information you'd trust they won't know and would steer you into doing it correctly. if you ask some one who knows... they're probably not to be trusted.

get some plastic, do some before and after readings, and you'll have site specific 'facts' to made informed 'decisions'. the word 'guess' is dangerous around here.

i've seen a bunch of posts here that recommend anything from plastic food wrap to garbage can liners to heavy drop cloths. the thickness, obviously, creates a sliding scale, your room creates a unique variable. that's some slippery math! .... which no one in there right mind would stand behind or inflict on someone who was asking for real help.

having said thaaaaaat........
watch for the difference between mm's and mil's. those in the heavy plastic camp mention 4 to 6 mils. garbage bags and heavy lawn bags sit between .5 and 4 mils. plastic drop cloths peak at around 6 mils.

also, these absorbers fitted with plastic should not be used in areas of early reflection.

do not put plastic on cornet straddling absorbers. it will bounce highs right back to the mix position. ( ....that's a edit. may have messed that one up the first time.)

so this doesn't answer you question, and for the most part just tells you things you already know..... which is a good thing. my mantra, gleaned from availing myself of the wisdom here is - test, do, test. then you have some facts to show, for those in the know, to show you which way to go.

i'm doing some readings to compare plastics this week. i'll be testing around 6 non reflection zone broadband absorbers. first without plastic, then the food grade stuff, then garbage bag-esque, then the 4 mil. oddly, it should only take a few minutes. should be enough to tell me about the trend of plastic in my room.

i'll post it, but in the grand scheme of things, it's won't be a resource,, it's a curiosity, like a dancing bear.

raticus

[L Diamond]

john sayers forum has some good info on this. i'd look there