Home Theater Forum and Systems banner

41 - 60 of 107 Posts

·
Registered
Joined
·
192 Posts
Discussion Starter #41
Thanks for your comment


I'm still working on the design, and trying to locate the port. I have a question, is there a problem if a locate the inner end side of the port near of the subwoofer? or should it be placed away from it? or is it not relevant?

regards
 

·
Registered
Joined
·
683 Posts
Just make sure you have at least one port diameter distance from the port opening to anything around it and you should be good. I have seen quite a few examples where the port opening was fairly close to the driver, and no ill effects were noted.
 

·
Registered
Joined
·
192 Posts
Discussion Starter #43
Just make sure you have at least one port diameter distance from the port opening to anything around it and you should be good. I have seen quite a few examples where the port opening was fairly close to the driver, and no ill effects were noted.
Thanks for your comment, so, based on this, I think I'm ok, I will continue and finish the design

Also, I just received some other components

  • Amp Behringer iNuke 1000
  • Four 6in flared ports
  • Connectors, speakon, XLR, RCA
  • Grill frame
Almost ready!!!
 

·
Registered
Joined
·
192 Posts
Discussion Starter #45
Hello everybody

I'm still working on the enclosure design, specifically on the bracing, but I have a doubt, I search in the forums and the web, but was not able to find a clear answer. Hopefully someone can help me.

My question is, is there any restriction or minimum open area when designing the bracings?

Regards
 

·
Registered
Joined
·
192 Posts
Discussion Starter #46
I think it's better to add a picture, for more clarity

This is one of the braces, this is special one, because the rounded holes or circles are designed for the flared port, so these are not open area. Only the triangles are open area. I have not calculated the area yet, but a rough guess is that only 30% is open. Is this ok? will be any issue with air movement inside the enclosure?

Regards
 

Attachments

·
Registered
Joined
·
403 Posts
Make sure the area of the brace openings is at least the area of the ports.
Could you open up the brace on the front side too? One large or 3 small round holes might be the easiest way to add surface for air movement.
Cutting 2 triangles out there would give the most area.
 

·
Registered
Joined
·
100 Posts
Could remove the piece that bisects the corner, too. Might want to thicken the circles slightly or double up the brace-- make two and laminate together.
 

·
Registered
Joined
·
683 Posts
I would imagine that having the open area equal to the port areas will still be a problem. In essence you would be lengthening the ports and not having a free volume. I hope a more knowledgeable person will chime in here, but I think you may have a significant problem with that size port taking up so much cross sectional area.
 

·
Registered
Joined
·
192 Posts
Discussion Starter #50
Make sure the area of the brace openings is at least the area of the ports.
Could you open up the brace on the front side too? One large or 3 small round holes might be the easiest way to add surface for air movement.
Cutting 2 triangles out there would give the most area.
Thanks, I was thinking in something like this, mean, that should be bigger than port area, but not sure if this enough

Could remove the piece that bisects the corner, too. Might want to thicken the circles slightly or double up the brace-- make two and laminate together.
thanks, this could be a good option too

I would imagine that having the open area equal to the port areas will still be a problem. In essence you would be lengthening the ports and not having a free volume. I hope a more knowledgeable person will chime in here, but I think you may have a significant problem with that size port taking up so much cross sectional area.
Thanks, this is my real concern

I will try to find another design that increase the area, just to be in the safe side.

Regards
 

·
Registered
Joined
·
192 Posts
Discussion Starter #51
Hello everyone

This project is still moving ahead, but slow. I spent several nights trying to figure out the bracing and ports on the triangular shape design, but I was not comfortable with the result and the open area that would be available. So, I don't want to have any risk of bad performance since I'm investing time and money, so I'm now taking a different direction.

Now I will work on a more traditional design, a square design with straight ports, so I would get a design that should deliver a performance according to the win ISD calcs.

I'm still targeting 500L (17.6 ft3), and after adding port, driver and bracing volume, I will be building an enclosure of 551L. 2 flared ports 6in diameter x 54.4 cm (21.4in) for 18 Hz tuning.

I will be using double layer for the baffle.

Internal dimensions are:

Width: 62cm
Depth: 80cm
Height: 120 cm

Inner port is 216mm away from the panel, so it's more than 1 diam away, so it should not be a problem.

See the new design:
 

Attachments

·
Registered
Joined
·
192 Posts
Discussion Starter #52
But I just would like to get your opinion regarding the bracing, please see the pics:

What do you think?

Is this ok?

I'm also planning to add a second layer to the bottom, because I'm planning to add some feet and I would like to have a good support.

any comments?
 

Attachments

·
Registered
Joined
·
100 Posts
The bracing looks good to me. Have you figured out how much it will weigh? At some point the weight and size of the feet would dictate whether you need another layer on the bottom. Or if you don't want another whole sheet on the bottom, you could put some corner bracing on the inside of the bottom.
 

·
Registered
Joined
·
192 Posts
Discussion Starter #54
The bracing looks good to me. Have you figured out how much it will weigh? At some point the weight and size of the feet would dictate whether you need another layer on the bottom. Or if you don't want another whole sheet on the bottom, you could put some corner bracing on the inside of the bottom.
Well, considering that I would be using 3 and a half MDF 3/4 sheets, and around 80 punds per sheet, and adding the driver weight, my guess is that it will be a little higher than 300 lb.

I like your idea about bracing inside, I will run some sketches.

I just got the material and the build will begin within next week.

Regards
 

·
Registered
Joined
·
683 Posts
I like your design :T This is going to be a nice looking sub!

Some thoughts: you are going to use a substantial amount of sheet goods for your bracing. Have you considered doweling or bracing with laminated cut strips to minimize how much effort you will have to put in for window cuts? I would put a dowel or laminated strip across your enclosure at all your current bracings' intersections.

By essentially breaking up the panels into smaller panels you not only increase their resonant frequency but increase their perceived strength as well. To do that you only need those intersections reinforced to get to that rule of thumb of no panel size over 12x12".
 

·
Registered
Joined
·
192 Posts
Discussion Starter #57
I like your design :T This is going to be a nice looking sub!

Some thoughts: you are going to use a substantial amount of sheet goods for your bracing. Have you considered doweling or bracing with laminated cut strips to minimize how much effort you will have to put in for window cuts? I would put a dowel or laminated strip across your enclosure at all your current bracings' intersections.

By essentially breaking up the panels into smaller panels you not only increase their resonant frequency but increase their perceived strength as well. To do that you only need those intersections reinforced to get to that rule of thumb of no panel size over 12x12".
No but sounds interesting. Let me see if I understand correctly, I have to replace all the window type bracing with some kind of rods?

In the other hand, if I continue with window type bracing, will I have the same results using MDF or plywood?

Regards
 

·
Registered
Joined
·
683 Posts
No but sounds interesting. Let me see if I understand correctly, I have to replace all the window type bracing with some kind of rods?

In the other hand, if I continue with window type bracing, will I have the same results using MDF or plywood?

Regards
I probably didn't make much sense - here's what I was getting at:

ALPHA-74.JPG

They could be rods or pieces of wood 3/4" laminated with another 3/4" to get a piece for one rod that is 1.5"x1.5" by whatever length you need. Doing this would eliminate the need to cut windows out of a sheet and would minimize waste (and likely keep weight down a bit).

Take a look at this thread http://www.hometheatershack.com/forums/sealed-subwoofer-build-projects/64052-stereo-integrity-ht-18d2-build.html from baniels.
 
41 - 60 of 107 Posts
Top