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Post by David on Oct 29, 2016 7:20:48 GMT
Hey everybody! So I just received 4 Roxul Safe N Sound 24 (2'x4') today. Each package contains eight 3 inch batts. My question is regarding what thickness I should use
for my reflection points and bass points. I planned on making bass traps with two 3 inch batts on top of one another wrapped with a non porous material, and broadband panels
with one 3 inch batt wrapped in a porous material. Would I benefit from building my broadband panels with more than just one 3 inch batt? I planned on placing them on the side
walls, ceiling, and directly behind my mixing point wall. What thickness would you recommend for each type of panel? Thanks in advance!
Warm Regards,
David |
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Post by rock on Oct 29, 2016 14:15:55 GMT
Hi David, You have left out some details like the dims of your room, if you're using membrane on the bass traps, if you're mean on "top of one another" like a sandwich or end to end, etc. Did you read all of Ethan's links about setting up a room and his tests with FRK vs non-FRK? Did you read Hexspa's free ebooK? Spread out absorbers as much as possible. 3" is fine for mid/hi reflections. Using thicker panels and/or spacing from the wall/ceiling will be more effective at low frequencies (3" is a little thin for bass traps; 4 to 6 and up is better). So there is a tradeoff between thickness and total area covered if you have a fixed/finite volume of absorption panel material as you do. Your 4 pkgs will yield 256 sq ft @ 3" thick. Here's a tool to give you a general idea of how much area you might need for a given RT60 and where your room modes are. amroc.andymel.eu/?l=13.5&w=10&h=7.5&ft=true&r60=0.6 just plug in your dims. Cheers, Rock |
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Post by Hexspa on Oct 30, 2016 9:42:20 GMT
Thanks for the pimp rock.
hexspa.com/listening-room-ebook hah
I like to keep it simple.
Make 16 6" panels, review resources to ensure correct placement, measure and review.
Thanks,
-m
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Post by David on Nov 11, 2016 6:42:36 GMT
Hey I appreciate the info guys! Sorry for not clarifying. I am making 6 inch panels cookie style. I am almost done actually.
The only thing I'm concerned about is the my room dims. I'm basically in a perfect cube. 10.4 x 10 that is 8ft high.
I read that your head shouldn't be directly in the center of the room. I've got other rooms, but they are very open and open into other rooms.
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Post by Nigel Spiers on Nov 11, 2016 11:30:32 GMT
Hi David,
That quantity of material should make a significant difference to the acoustics of your room.
It looks a reasonably rigid product so before you go too far in terms of glueing pieces together or covering them with fabric you may want to experiment by leaning them vertically against the walls of your room in various positions.
As a starting point you may wish to place 4 across all 4 corners of your room two high (8 in total). With the remainder, four across the back wall behind your mixing position (get them head height by placing them on dining chairs and the remainder either side of your mixing position again on dining chairs.
Good luck with your project.
Best Regards
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Post by rock on Nov 11, 2016 17:58:47 GMT
Hi David,
Nigel has good suggestions and I'll add that the floor/wall corners are easy places to experiment with bass trap placement too. Remember, your corner bass traps placed out of reflections zones should have a foil, paper or plastic membrane spray glued to only the front for improved LF absorption, but the back should be porous.
I hate to say this but I just re-read your OP and I see your plans include using "NON POROUS" covering for your bass traps. From what I know, I don't think that's right. as I mention above, the only non porous membrane is on the front. I believe the total covering with non-porous will work but I'm pretty sure it's not optimum. Hopefully Ethan can confirm or refute this.
Regarding using another room: It's OK to have a room open to another room like a living room/dining room and it's probably better if the total length/width gives you better modal distribution. The partial walls where one room transitions to the other are probably not much of a problem but can be treated with bass traps if they are large enough like 2-3 feet or more. For mixing or listening (as opposed to recording) it's best to be as symmetrical as possible but even asymmetries can be corrected to some extent with speaker/listening position and absorber placement.
Cheers,
Rock
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Post by David on Nov 19, 2016 21:16:05 GMT
Thanks for the advice guys! I had read that for bass trap material it is benificial to have a non porous material. The bass frequencies will still pass through but keep mids and highs reflected to keep the room alive. I went with a semi porous material and put a garbage bag around it.
As for the plastic garbage bags, you've got me concerned. I did not glue it to the face. I simply put the garbage bag around the rockwool and tied it off. I actually did that to help with mids & highs. Hopefully someone can clarify if this is detrimental in not having it glued and around the back.
For reflective spots I planned on just wrapping them in a purous material without plastic. I appreciate all the feedback!
Cheers,
David
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Post by rock on Nov 20, 2016 0:17:12 GMT
Hi David,
If you read Ethan's materials, I'm pretty sure what you will find is that what is recommended is to attach (spray glue works very good) plastic (or paper) to the front only. Leave the sides and back porous (fabric covering is OK). The primary purpose of the plastic membrane is to improve the low frequency performance of the absorber, the fact that it does not absorb as much mid/hi is a by product; not the other way around. So I think you should spray glue plastic only to the front.
Now, as far as why the back is left porous is, I can only guess so here it is: The sound that does pass through the absorber and reflects back into it after bouncing off the wall will be absorbed more efficiently by the porous back as opposed to it if it were covered with plastic.
Yes, for reflective areas, cover just material. And just to mention again, spacing off the wall (typically equal to the absorber thickness) gives you "free" LF performance extending about 1 octave.
Cheers,
Rock
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Post by David on Nov 20, 2016 0:53:51 GMT
Thanks rock! I've been scouring the web in search of data. I haven't found any reason why slipping a trash bag over the rockwool would hinder bass absortion.
My lungs are a bit sensitive, and I thought that may be the ticket. I've already built 4 that way. Still scratching my head in debate about taking them apart or just continuing with the current model.
I may just build the rest with only glued plastic on the front. I've also read glued plastic on the back for reflection spots. So many opinions out there.
Thanks again,
David
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