the elephant box... to be built by BJfish

[BrianChia 10+ year member]

Looks BEEFY.

Somehow I don't think rigidity will be a problem... //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[nineballsafety8 10+ year member]

the bracing in this box is what makes it so unbelievable strong (aside from the 240 lbs. of trupan light of course). if you look carefully the ports tie every wall of the enclosure together. the ports are even braced in two places, once on the face of the side of the port and then again, butted up against the end of the flare. BJ, "you are going to need some REALLY long screws for that part"

 

[BrianChia 10+ year member]

Also BJ builds with rabbeted joints unlike most people here...

//content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

 

[bjfish11 5,000+ posts]

Also BJ builds with rabbeted joints unlike most people here...
//content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

Yep.

Looks good man, Ill get you that quote tonight.

 

[audioholic 5,000+ posts]

When I looked at the box plans, my eyes immediately went to the double walled port, with its bends. And my first thought was how the hell are you gonna do that.

Here's my thinking. You can't make the linear cuts (for the round bend shape) after the boards are already laminated together, it would just cut the inner panel in half. So Im guessing you'll have to bend each piece seperate, then laminate them together once they are already in the bended shape. Sounds very difficult getting the raiuses to match up exactly.

I suspect you'll do it after laminated, even thought my though is it wont work. You'll prolly make it work. lol Just post some pics of that stage of the project if you would please.

Also, Im not sure I understand the reasoning for having the port walls be double thickness. They really shouldn't have the stress applied to them the outside walls do. Im designing a double walled box right now and its port walls will be single. Perhaps the problem with bending a double layered wall for the port isn't even necessary?

 

[Slowd N Throwd 10+ year member]

im interested to see how the double walled bends are going to work.. i dont think iv ever seen that befor, i believe BJfish can do it though

 

[nineballsafety8 10+ year member]

When I looked at the box plans, my eyes immediately went to the double walled port, with its bends. And my first thought was how the hell are you gonna do that.
Here's my thinking. You can't make the linear cuts (for the round bend shape) after the boards are already laminated together, it would just cut the inner panel in half. So Im guessing you'll have to bend each piece seperate, then laminate them together once they are already in the bended shape. Sounds very difficult getting the raiuses to match up exactly.

I suspect you'll do it after laminated, even thought my though is it wont work. You'll prolly make it work. lol Just post some pics of that stage of the project if you would please.

Also, Im not sure I understand the reasoning for having the port walls be double thickness. They really shouldn't have the stress applied to them the outside walls do. Im designing a double walled box right now and its port walls will be single. Perhaps the problem with bending a double layered wall for the port isn't even necessary?

not that im saying you don't know what you are talking about, because you are a senior member and have seen your name quite a few times in intelligent discussions on forums here before however... with pressure levels of upwards of 170db inside a ported enclosure what makes you think the the stress on ANY wall would be any less than any other... its basic physics... true SPL is based on atmospheric pressure, not volume... and the number of atmospheres within a port enclosure remain constant through out the enclosure with the exception of about a 30% at corners due to standing waves within the box... ( a sphere is the only enclosure to truly eliminate atanding waves within an enclosre.)... and any way, the double thick port walls are more to support the face of the enclosure that holds the drivers than the "make the ports stronger"... the bracing is set in the enclosure to minimize turbulence... so there are not any braces that run perpendicular to the venting voice.

 

[audioholic 5,000+ posts]

So the port wall absorbs the same stresses as an exterior wall? A port wall will have the same pressure on both sides of it, an exterior wall will not. Be it 170db's worth of pressure, or atmospheric pressure. Its the difference in pressures on two sides of a wall that would cause the panel to flex.

Many people brace a box will simple dowel rods. Id think a full 3/4" panel would suffice, 1.5" being over kill. But overkill isn't necessarily bad, was just asking.

Im not sure what my post count or experience has to do with answering my questions.

Cheers.

 

[Immacomputer 10+ year member]

View attachment 26500922alright boys, here it is... after about 18 hours of non stop beating my head against the wall with anticipation... and lost of talking with bjfish and DJL from AQ i finally have the design ironned out. the elephant box is on the way... and is going to be mean as ****!!!//content.invisioncic.com/y282845/emoticons/eek.gif.771b7a90cf45cabdc554ff1121c21c4a.gif//content.invisioncic.com/y282845/emoticons/eek.gif.771b7a90cf45cabdc554ff1121c21c4a.gif

It does kind of look like an elephant from that angle.

I like the design but I think that bracing the port flares like this would be a much stronger and easier route (with more obviously). It would be really easy to get the exact radius using cardboard test pieces and a skilled jigsaw hand:

Either way, I know BJ will be able to pull it off.

 

[nineballsafety8 10+ year member]

So the port wall absorbs the same stresses as an exterior wall? A port wall will have the same pressure on both sides of it, an exterior wall will not. Be it 170db's worth of pressure, or atmospheric pressure. Its the difference in pressures on two sides of a wall that would cause the panel to flex.
Many people brace a box will simple dowel rods. Id think a full 3/4" panel would suffice, 1.5" being over kill. But overkill isn't necessarily bad, was just asking.

Im not sure what my post count or experience has to do with answering my questions.

Cheers.

i understand what you are getting at, but the pressure on the sides of the port are not actually the same... if you go to DDAUDIO.COM they describe it a lot better than i do... but although the air in a port is constantly moving (back and forth), the air "within" the port becomes someone static, in that it never actually moves more the the distance the motor structure/structures of the drivers within the box can push it. so while a port is "breathing" at whatever velocity and frequency, the port is essentially using the same air over and over... there for the port becomes an additional driving surface (much liking adding more drivers), therefore the pressure inside the box an all surfaces (including the port) stays the same, while the pressure within the port stays at no true "pressure" but with much movement and volume.... atleast thats what my BAS in Physics and 3 yrs as a proffesional installer and 4 years in the amateur circuit... but then again opinions are like *** holes, everybody has one and most of them stink... but thats the way i understand it.

and i appreciate the input on different bracing, but this design is a dream come true for me and is pretty set in stone... thanx

 

[bjfish11 5,000+ posts]

When I looked at the box plans, my eyes immediately went to the double walled port, with its bends. And my first thought was how the hell are you gonna do that.
Here's my thinking. You can't make the linear cuts (for the round bend shape) after the boards are already laminated together, it would just cut the inner panel in half. So Im guessing you'll have to bend each piece seperate, then laminate them together once they are already in the bended shape. Sounds very difficult getting the raiuses to match up exactly.

I suspect you'll do it after laminated, even thought my though is it wont work. You'll prolly make it work. lol Just post some pics of that stage of the project if you would please.

Also, Im not sure I understand the reasoning for having the port walls be double thickness. They really shouldn't have the stress applied to them the outside walls do. Im designing a double walled box right now and its port walls will be single. Perhaps the problem with bending a double layered wall for the port isn't even necessary?

I really dont think its going to be as hard as it seems it might. I will cut and bend each piece separately, then laminate them together.

With Chris' skills in designing it up, Im pretty positive we will be able to pull it off. If by chance we cant, we will find an alternative.

 

[audioholic 5,000+ posts]

i understand what you are getting at, but the pressure on the sides of the port are not actually the same... if you go to DDAUDIO.COM they describe it a lot better than i do... but although the air in a port is constantly moving (back and forth), the air "within" the port becomes someone static, in that it never actually moves more the the distance the motor structure/structures of the drivers within the box can push it. so while a port is "breathing" at whatever velocity and frequency, the port is essentially using the same air over and over... there for the port becomes an additional driving surface (much liking adding more drivers), therefore the pressure inside the box an all surfaces (including the port) stays the same, while the pressure within the port stays at no true "pressure" but with much movement and volume.... atleast thats what my BAS in Physics and 3 yrs as a proffesional installer and 4 years in the amateur circuit... but then again opinions are like *** holes, everybody has one and most of them stink... but thats the way i understand it.
and i appreciate the input on different bracing, but this design is a dream come true for me and is pretty set in stone... thanx

If what you are suggesting is true, then the inner port wall itself would take the brunt of the stress/pressure, and the outer wall (and port wall) wouldn't need to be as strong.
Eitherway, like I said above, over built is a good thing. Good luck with your project. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

I really dont think its going to be as hard as it seems it might. I will cut and bend each piece separately, then laminate them together.
With Chris' skills in designing it up, Im pretty positive we will be able to pull it off. If by chance we cant, we will find an alternative.

Yeah after thinking about it more bending each piece is the only way to go. With some jigs to replicate each bend radius needed, fitting the two pieces together post-bend shouldn't be as hard as I thought. Not suggesting it'll be easy lol, however Im sure you'll make it look that way.
Looking forward to watching another one of your projects unfold.