Lighter bass traps for small budgets

[kesslerjesus]

I'm just asking for advice on wether or not this plan will work.

I purchased 32 pillow covers (pics included), size 1.5'x3' that can accomodate pillows that are 4inches thick.

I am planing to purchase fabric to add another layer and cover the pillow covers so that they wont look odd when on the walls. I will hang on the walls with some clips I have left from a past purchase. (TOTAL price for project: 100 to 110 dollars (50 for covers, 30 for fabric, 20 or 30 for insulation)

Home depot is selling R-13, the 3 feet, 3.5" thick, 32 foot long rolls for 9 dollars, so I'm planing to maybe buy 2 or 3 packages and stuff some of the pillows a bit more.

Will these small and light traps work to make the room more mix friendly? (will have 32 of these traps at my disposal for an 8' wide x 9' long x 11' high room)

Also, are there any precautions should I take into consideration when putting the traps together and working with r-13? thanks!

[Glenn Kuras]

For the early reflection point is should be ok, but for the bass trapping you really need it 4" thick and should be rigid fiberglass or mineral wool. You can use fluffy fiberglass but needs to me much thicker.

[kesslerjesus]

UPDATE!

[kesslerjesus]

Large pics i guess.

[kesslerjesus]

now I have 31 traps

3.5 inches thick
2 feet long by 1.5 feet wide

going to use two per pannel so that I have a total of 15 and 1 left

time to use the fabric to cover em up!

Total price:
$50 for pillow covers with zipper
$20 for 60 feet of 1.5 feet by 3.5 inch thick insulation
$30 dollars for 9 yards of 6 feet wide fabric from walmart

CHACHING!

taking a break because the material is a bitch itchy, even with a mouth cover, glasses, gloves and a long sleeve sweater!

[kesslerjesus]

15 pannels, 1 half pannel in green

now i just need to either sow, stick or glue the edges together to close em up and then hang em on the walls/corners

each pannel weighs around a pound! makes it much easier to put em up without needing to drill holes on the walls since this is an apartment

[icelandgifts]

Looking quite nice, let us know how it will work. I've similar plans for my room so I'm quite interested to hear how effective this will be.

[Glenn Kuras]

taking a break because the material is a bitch itchy, even with a mouth cover, glasses, gloves and a long sleeve sweater!

Yes you really want to cover as much of your body as possible when working with rigid fiberglass or mineral wool. thumbsup

[Weasel9992]

Originally Posted by Glenn Kuras

For the early reflection point is should be ok, but for the bass trapping you really need it 4" thick and should be rigid fiberglass or mineral wool. You can use fluffy fiberglass but needs to me much thicker.

Just wanted to emphasize this point. What you've got now will work great for general decay time reduction, but it's not going to do a thing to control low end. You'll need thicker, denser traps for that.

Frank

[kesslerjesus]

Thanks for the advice. Keep in mind though, that I made it so that the traps are of soft mineral wool, but they are 7 inches thick.

I have the project on hold since I realized I am going to need some spray adhesive to seal the pannels, that will take like 10 dollars more, but I'l get it tomorrow.

[Lemontree]

Originally Posted by kesslerjesus

Thanks for the advice. Keep in mind though, that I made it so that the traps are of soft mineral wool, but they are 7 inches thick.

I have the project on hold since I realized I am going to need some spray adhesive to seal the pannels, that will take like 10 dollars more, but I'l get it tomorrow.

Staples? ...just a thought

[xaMdaM]

Originally Posted by kesslerjesus

Thanks for the advice. Keep in mind though, that I made it so that the traps are of soft mineral wool, but they are 7 inches thick.

To equal the density of 1" of 3 lb/cu ft of 703 or mineral wool, you'll need ~21" of pink fluffy.

[kesslerjesus]

Damn, ah well, I just wanted something that wouldn't be too heavy to hang on the walls/corners. I think the 703 bass traps are going to have to wait until I move out from here :(

Hopefully these will make the listening environment tolerable though

And thanks for the suggestion about staples, might be much easier to try that.

[PaulP]

Originally Posted by kesslerjesus

Damn, ah well, I just wanted something that wouldn't be too heavy to hang on the walls/corners. I think the 703 bass traps are going to have to wait until I move out from here :(

According to Andre (avare) regular insulation in the 10" to 16" thick range is
effective down pretty low, see this post, so maybe your traps aren't that
bad. If you double your 7" traps they may be pretty good.

Paul P

[avare]

Originally Posted by PaulP

According to Andre (avare) regular insulation in the 10" to 16" thick range is
effective down pretty low, see this post, so maybe your traps aren't that
bad. If you double your 7" traps they may be pretty good.

Paul P

Thanks Paul. There is nothing I can add to that.

Andre

[kesslerjesus]

Thanks, I might actually do that. I wouldn't mind doubling up a few traps for the corners and using the others (7inch ones) on the walls.

Really helpful, thanks fellas!

[tmrstudio]

Won't the traps be quite a bit more effective if they are hung over an air cavity?

[Weasel9992]

Originally Posted by tmrstudio

Won't the traps be quite a bit more effective if they are hung over an air cavity?

Getting some airspace behind a trap is always a good thing...it'll extend the low end coverage of the trap a bit and make it a little more effective all the way around. The general rule of thumb is to get as much space behind a trap as you have inches of treatment.

Frank

[kesslerjesus]

Yes, that's the plan. I will be leaving space between the walls and the traps, but around how much is suggested?

[Weasel9992]

Originally Posted by Weasel9992

The general rule of thumb is to get as much space behind a trap as you have inches of treatment.

Frank

[PaulP]

Originally Posted by Weasel9992
The general rule of thumb is to get as much space behind a trap as you have inches of treatment.

Won't that get a bit out of hand if the trap is 14" thick ?

Paul P

[Brainchild]

Originally Posted by xaMdaM

To equal the density of 1" of 3 lb/cu ft of 703 or mineral wool, you'll need ~21" of pink fluffy.

Fluffy pink is about .6-.8 lb/cu ft, which would make it more like 4 or 5 inches, just in terms of density.

[avare]

Originally Posted by Weasel9992

The general rule of thumb is to get as much space behind a trap as you have inches of treatment.

Aargh! You know that the absorption properties of a trap are dependent upon the gas flow resistance of the material. A gap may, or may not be,of value depending on the material. Facilites designed with budgets to test actual absorption characteristics of absorbers use up to around 2:1. The BBC A1 absorber used a 5:1 gap to material ratio.

Andre

[Weasel9992]

Originally Posted by avare

Aargh! You know that the absorption properties of a trap are dependent upon the gas flow resistance of the material. A gap may, or may not be,of value depending on the material. Facilites designed with budgets to test actual absorption characteristics of absorbers use up to around 2:1. The BBC A1 absorber used a 5:1 gap to material ratio.

Andre

Yes, absolutely you're right Andre...no argument from me. That's why it's just a rule of thumb and not an acoustics law or anything. When I use it typically I'm balancing the need to maximize space in a small room with the need to maximize the effectiveness of the absorbers. It also assumes the use of something like rigid fiberglass or mineral wool.

Frank

[PaulP]

For the low frequencies, if I understand things correctly, the thickness of the
absorber determines the bandwidth of the absorption, and the air gap (plus
half the thickness of the absorber) sets the center frequency. There are a
few other things thrown like the diffraction at the boundaries and various
reflections.

Paul P

[kesslerjesus]

A gap wasn't possible between the traps and walls on most of the parts, but a few corners were. I actually resulted to sealing 3 of the 4 sides of the traps, leavin one to allow me to use a staple gun to place them on the walls (couldn't use nails).

The right side of the room was odd to fix since I have to use both those doors to enter/leave the room and the other one is the closet, so I placed the traps so that I can do both without a problem or having to take them down. I also listened to all your suggestions and moved my desk to the other side of the room, putting the bed in the odd corner where the desk used to be.

Might not look pretty, but I can deff tell the difference when listening to mixes. My room had an uncontrollable echo before making the change, and I can hear a difference in the snares and kicks I in two mixes I've recently listened to. I also realized that my past mixes had a lot of reverb. The sound on the monitors actually decreased a bit too, they don't sound as loud as they did before.

Thanks for all your suggestions, I'l make sure to spend the cash and get better treatment whenever I move to a bigger place, but for around 100 bucks and the crappy room i'm currently stuck with, these will do

Pics:

[avare]

Originally Posted by PaulP

For the low frequencies, if I understand things correctly, the thickness of the
absorber determines the bandwidth of the absorption, and the air gap (plus
half the thickness of the absorber) sets the center frequency. There are a
few other things thrown like the diffraction at the boundaries and various
reflections.

Paul P

The thickness determines the low frequency cut of point. Thickness includes the material and the air gap. The larger the air gap, the larger the dip at multiples of wavelength/2 frequencies.

Andre

[avare]

Originally Posted by Weasel9992

When I use it typically I'm balancing the need to maximize space in a small room with the need to maximize the effectiveness of the absorbers. It also assumes the use of something like rigid fiberglass or mineral wool.

Thanks Frank, but I am now confused. There are almost always qualifiers on any generalization in acoustics and your material one is one. It is a good example of why I am loath to give them. So many ifs buts excepts etc.

Using gaps to maximize absorption while minimizing space used? This has me bamboozled. Please expand.

Space conscious, but dieting,
Andre

[TheEqualizer]

Originally Posted by avare

Thanks Frank, but I am now confused. There are almost always qualifiers on any generalization in acoustics and your material one is one. It is a good example of why I am loath to give them. So many ifs buts excepts etc.

Using gaps to maximize absorption while minimizing space used? This has me bamboozled. Please expand.

Space conscious, but dieting,
Andre

+1.

[Weasel9992]

Originally Posted by avare

Using gaps to maximize absorption while minimizing space used? This has me bamboozled. Please expand.

What I mean is using a gap to expand low end extension. In rooms where there's not a lot of wall space, getting all the low end extension possible is critical.

You're right. I should have qualified it as a generalization. I try to do that when I'm generalizing and this time I just didn't.

Frank