Bass Traps

[cincy_kid]

Ok, so as I mentioned I was going to make some bass traps for my very small closet studio as my next step for treatment. After doing some research I am confused on something (imagine that )

When reading Ethan's Acoustic Treatment and Design page, he illustrates fiberglass bass traps like this. Straddling the fiberglass using some 1x2 to secure it to the wall.

He says, and I quote:
When the rigid fiberglass is mounted in a corner like this, the large air gap helps it absorb to fairly low frequencies

This is how I originally was going to make my traps.

Until I did some more research and everything I saw on bass traps, looked like these, which also supports the notion of people stacking triangles from floor to ceiling.

So with traps like these, it seems they will be flush against the wall and tri-corners.

I was going to make them like this:

(The purple thing is a shelf I was going to sit the traps on)

Do these traps and Ethan's traps serve completely different purposes? For my small space is one better than the other?

Someone shed some light?

Thanks ~

 

[SonicClang]

There are a couple things you need to think about to make the decision on which way to go. Foam, no matter how well it is treated to be fire retardent, is still flamable. And when it goes up in smoke, that isn't good stuff. Its fumes are normally toxis and don't smell like roses.

Fiber board isn't flamable, and it's a much cheaper alternative, and works just as well.

A lot of people like to keep foam completely out of their studios. Any time I can find an alternative I'm going with it.

 

[cincy_kid]

Well, since I already have the 703 for absorption panels on the walls and have quite a few sheets left, I will go ahead and use them for now.

What would cause the fire anyways? All electrical things are turned off every night in the room and nothing is left on, but do you mean while I am in the room recording? (fire extinguisher to the rescue! )

But anyways, I would like to know which trap method I should use in my original post and what the difference is and why I see different kind of traps and if they all will work as well in my small room.

Thanks ~

 

[apl]

What would cause the fire anyways?

Famous last words!

 

[apl]

Just do this.

 

[cincy_kid]

Famous last words!

LOL, dont scare me!

 

[cincy_kid]

Just do this.

So is Ethan's method just for absorbing lower bass frequencies? I mean why are other bass traps flush against the wall with no air gap?

 

[SonicClang]

What would cause the fire anyways?

Don't get cocky kid!!! You better find some wood and knock on it pronto! Don't ever say "it can't happen to me". I know two guys who work in the fire department and they've told me some stories that make me very paranoid about fire. That's why I keep a FIRE EXTINGUISHER IN MY STUDIO.

There are lots of things that can cause a fire. And you may THINK you've turned all your electricals off in your room, but there's still voltage at the outlets, unless you're also turning off the circuit breakers. A loose connection at an outlet or light switch could create heat, and hence create fire.

I'm like the fire marshall around here. I'm always the one pointing out fire hazards. But that's because after 6 years of working on a studio I'm just about to finish up, I'd hate to see it go up in smoke.

 

[apl]

So is Ethan's method just for absorbing lower bass frequencies? I mean why are other bass traps flush against the wall with no air gap?

It would be better to fill the space, but I don't think you've got enough material.

 

[cincy_kid]

Yea, fire extinguisher will be in mine too! Now you have me paranoid....

Hey APL, I think I have the material to do like in my diagram above. 1 sheet of 2x4 will cover 1 tri-corner and if i do all 8 corners that uses my last 8 sheets. (but then no clouds..hrm..)

Oh, btw I was doing some reading on Ethan's RealTraps.com and was just wondering, for his traps, doesn't he use foam too? 703, 705 or something equivilent?

Get on him Sonic about Flammables!

 

[apl]

Hey APL, I think I have the material to do like in my diagram above. 1 sheet of 2x4 will cover 1 tri-corner and if i do all 8 corners that uses my last 8 sheets. (but then no clouds..hrm..)

It's up to you, but I'd expect better results the other way because you'd have more treated area that way.

 

[pandamonk]

I'd do as apl suggests 'cause that means you have all your corners with bass traps instead of a bit of a couple of them. And i noticed in your pics that you have a panel at your door. You could use that as your cloud. Only thing wrong with it is the wooden frame. Wouldn't want that hanging above my head.

 

[cincy_kid]

My method would cover all 8 tri-corners. The straddling method seems to possibly take up more space than I want to give up. However, I would be willing to give up the extra space if someone can tell me that having the air gap behind the trap is better than packing it flush to the wall (in my very small room.)

I was going to keep that vertical panel on the wall for extra absorption since I will be singing in that corner (with my back to the corner), and then I think I will make a couple of these traps here, and put them in front of me to absorb the first reflections of my vocals.

Good idea?

Just trying to think about the corners atm....

 

[bpape]

It's not the air behind it that gives the benefit, it's the distance from the face of the insulation to the hard boundary. That distance gets you closer to the 1/4 wave length of deeper frequencies where the most efficient absorbtion occurs with velocity absorbers.

There are 4 thing that can impact how deep an absorber will be effective:

1. Thickness
2. Density (to a point)
3. Distance from the boundary
4. Gas flow characteristics

When doing a solid corner instead of straddling it (assuming the same material), the thicker one will do a better job down lower.

 

[cincy_kid]

Hrm, thanks for that explanation Bpape. I am not very technical when it comes to this stuff but thanks all the same. Meaning I am not sure how deep I even want it, etc.

 

[Innovations]

I recently had a small bit of wall above the door that I felt would be a good place for a bass trap, So I took a two inch panel of leftover 703 and cut it on the slant to make a four inch thick bass trap with a just over one foot diagonal face. Here is a diagram looking from the two foot edge of the panel

 

[bpape]

Well, if you figure that you have 4" of 703 straddling a corner, you have 4" of thickness, 3lb density, and about 20" from face to deepest part of the corner.

If you have solid triangles, you have 3lb density, about 17" from the deepest part of the corner (yes they can actually take up a bit less room this way), but 17" of THICKNESS at the deepest point too.

If you want a compromise for less money, some people use fluffy fiberglass or acoustical cotton in triangles and then face it with 2" or 4" of 703. Best of both worlds - thicker, solid, front is dense, back is fluffier (OK when using extra thickness), farther from corner, etc. (and cheaper)

 

[cincy_kid]

Cool Bpape! That makes more sense to me

However, I started to play around with tracking last night and got frustrated. With the room being so small, it was hard for me to get comfortable with my acoustic guitar, sitting down in my chair, with SP B1 in mic stand bent down to line up with it. Either thje neck would bump the door, or body would bump the desk.

I have to figure out what to do here, maybe just need to move things a bit...

 

[skaman]

Can i make this trap by gluing the fiberglass on gipsum boards or wood boards or must it be only fiberglass???

Do I fix it on the wall or must it be selfstanding and little away from the wall??

thanks guys.

 

[cincy_kid]

can u say Hi -jack?

just kidding man, but being a noob I will try and give you an answer. yes it can be attached to wood and if you have it straddling the corner like in your diagram then it will have space behind it.