Well,
It`s just incredible the rich knowledge i discovered here!!! and i have another question...i`m making my own basstraps (thanx Ethan) i dont know nobody down here in Venezuela who own`s a basstrap or something...so, i`m doing my version...50cm x 10cm and 220 cm tall (please do the conversions) i`been thinking...if i have some paralel wall...may be i can bend the basstraps plywood a little...then, the high frecuencys gonna be reflected in diferents angles, so i can avoid ringing or something...the question is: the resonator inside gonna work in this way? does the low frecuencys gonna impact the fiberglass and stay right there between the wall and fiber? thanx for youe answers in advance...
I presented this question in another forum, and in the end the bottom line was one of two options : 1. "No, it will not be as effective because you increase stiffness as you bend the face (among other reasons)" and 2. "Try it and let us know how it goes."
Even if the facing is pre-bent into shape, you change the structure across the face thru the bend. BUT- let it be known that if I see somebody selling one of these in a few weeks I am going to be kicking myself!
JeffZ
"We are simultaneously the most loved, hated, feared, and respected nation on this planet. In short, we're Frank Sinatra." --Dennis Miller
Special thanks to the 73rd Ranger Regiment- you DO lead the way!
A bent resonator could actually work very well. I've mentioned in other forums that one could build a more efficient panel resonator by designing it like a loudspeaker - a lightweight rigid panel suspended around its perimeter with a flexible airtight cloth. A curved panel would be even more rigid, plus it would have those beneficial reflective characteristics as well.
The diagram below is a cross section view illustrating the concept. The blue areas depict the flexible airtight cloth suspension. The curved panels can be made by laminating two or more thinner sheets of plywood or veneer together while they are bent over a curved form.
In this design the panel curvature will have almost no effect on the absorption efficiency.
Thomas
Last edited by barefoot on Sat Jan 10, 2004 10:07 am, edited 2 times in total.
Thanx Barefoot!!!
i`m glad that a little bend doest affect the effectivity of the trapp, in the other side, what do you think about the highs reflection?
Curved panels will disperse high frequency reflections better than a flat panel. However, I think these curved panels would be better suited as secondary diffusive elements rather than primary devices indented to help fix early reflection problems.
And remember that you need to use a flexible suspension in order for this design to work. Rigidly mounting the curved panel to the frame like a normal panel absorber will not work.
And remember that you need to use a flexible suspension in order for this design to work. Rigidly mounting the curved panel to the frame like a normal panel absorber will not work.
Like a loudspeaker driver. It has a flexible rubber or foam surround that holds the cone to its frame.
So, for the absorber you would cut the panel a couple centimeters smaller than the frame. Then you stretch and glue strips of fabric between the panel and the frame. Finally you make the fabric air tight by coating it with a thin layer of silicon or latex caulk.
Maybe is my poor english...but, can you explain me the flexible thing in the bass trapp a little more? maybe u can add a graphic or something...you know, for dummies...
Aziel, Barefoot already gave you a drawing that shows what he's talking about. Then he explained it thoroughly in following posts. If you're still having a hard time understanding, you should probably build something simpler.
For what you sound like you're trying to do (trap bass, minimise reflections at the mix position) you would probably be happiest with building slant-faced versions of Ethan's designs - if you made the top and bottom wedge-shaped, so that the part that goes toward the REAR of your room is narrower than the FRONT part of the trap (4" narrower for every 2 feet would work fine) that would break up your parallel walls enough to treat flutter echoes AND it would reflect AWAY from your mix position to improve the imaging from your speakers.
Other than the slanted faces, you should build them exactly as Ethan's plans show. If your version is 50 CM wide, then it should be 10 Cm deep at the shallow side, and at least 16 CM deep at the deeper side.
The deeper side should go toward the FRONT of the room, the end your speakers are located at.
You should build at least two of these for each side of the room, three would be better. The center of each group on each side of the room should be halfway between you and your speakers, up against the side wall, with the deeper part of each trap to the front of the room.
Unless your room is large, (more than 3.5 meters from the back of your head to the rear wall when you're sitting at the mix position), then the REAR of the room should have absorbent on it or you will get early reflections from that rear wall.
I hope that helped... Steve
Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...
I am just seeking clarification-
Are you saying (Barefoot, and Knightfly I assume agrees as he didn't counter) that bending and laminating a curved front surface will not throw off the Q of the trap, or cause some weird problems with it as the density varies across the face. Will there not be problems across the face as you move from compression to expansion, then factor in the areas where glue is at different or no depth creating pockets of air inside?
Hey, I'm looking to do this same thing. I'm on your side here. But I was pretty much sold on the idea that the only way to effectively and predictable (withing reason) is to use a pre-shaped face. Like an extruded space age material like...plastic..or something.
Thanks.
Jeff
"We are simultaneously the most loved, hated, feared, and respected nation on this planet. In short, we're Frank Sinatra." --Dennis Miller
Special thanks to the 73rd Ranger Regiment- you DO lead the way!
Is there anything wrong with all those drawings in Everest's books? He goes into detail about how to build these things and the absorption coefficients to expect.
But u need more space if u want to get real Low ! I don't know if BareFoot's design may be take less space like a panel trap ? seems they are a bit different in design, what about the top and bottom on BareFoot trap, should be closed or not ?
Thanx
Feni
Yes, the entire perimeter of the front panel should be sealed with the flexible suspension.
Actually it might be easier to make the front panel bulge out in both the horizontal and vertical planes, such that the perimeter is flat. Hopefully this illustration makes sense.
Thanx BareFoot
I think it is cool ! for me it looks better than the 1st one u post.
Actually it might be easier to make the front panel bulge out in both the horizontal and vertical planes, such that the perimeter is flat. Hopefully this illustration makes sense.
It make sense for sure, but for a beginner DiY-er like me, it seem a bit hard to make the front panel bulge out, are this front panel is one piece of plywood or 4 ? Barefoot ! me and others inexperenced diy-er will be more than appriciated if u can share the tricks !
Thanx a lot !
Feni
