New at building speaker box..Have a question

[syzygylock]

Hi all, I'm looking to make DIY speakers and I've looked at a lot of DIY speakers diagram and stuffs. But one thing that I'm not clear on is the internal speaker's box construction. The diagram didn't specify much or any at all, yet from looking at many other DIY projects and cabinets, I see the constructions varies greatly. So, do you do whatever and make sure the internal bracket supports the box? Thanks,

[ThomasW]

The sticky thread projects posted in our Missions Accomplished section all show the internal construction of the boxes.

[syzygylock]

I was actually looking at the RS180 Modula MT thread and I saw 2 different brackets support and none of which has information on how to build it. I know that one was from PE's pre-built cabinet. I went to PE and check out their diagram and still no dice.

P.S. I also see that there're triangle bolt holders at each of the four corners of a cabinet, so we just cut them out from other pieces of wood and glue them in right?

Thanks,

[---k---]

I was actually looking at the RS180 Modula MT thread and I saw 2 different brackets support and none of which has information on how to build it. I know that one was from PE's pre-built cabinet. I went to PE and check out their diagram and still no dice.

P.S. I also see that there're triangle bolt holders at each of the four corners of a cabinet, so we just cut them out from other pieces of wood and glue them in right?

Thanks,

It just isn't clear what you are talking about. Bracket supports??? Don't know.

The triangle bolt holders at each of the four corner is, I think I understand your question, part of the PE boxes, used for the removable front baffles. They're only needed if you want a removable front baffle.

The location of the internal braces really isn't that critical. Just build a box that is sufficiently stiff with the right volume and baffle size and you're fine.

[ThomasW]

The PE boxes have a full sized brace in the middle of the box. It's the thing seen here with the 2 big holes in it.



The triangle things in the corners aren't really braces, they hold the nuts so the front baffles can be removed. Most from scratch builders aren't making boxes with removable fronts so the triangles aren't needed.

[yousuredo2]

your braces can be anyway you want them...
any size hole in them, as thick as you want etc...

[syzygylock]

That's exactly what I was talking about. I see different cabinets with different internal support (especially in the tall towers). My question was, is it necessary to build it to be exactly the same as the example or we can just do whatever or it's not necessary at all? If we need to build it, is there a certain acoustic design that we need to follow? Thanks,

The PE boxes have a full sized brace in the middle of the box. It's the thing seen here with the 2 big holes in it.



The triangle things in the corners aren't really braces, they hold the nuts so the front baffles can be removed. Most from scratch builders aren't making boxes with removable fronts so the triangles aren't needed.

[ThomasW]

That's exactly what I was talking about. I see different cabinets with different internal support (especially in the tall towers)

Let's focus on what you're building, which is? Modula MT, minitowers, or what?

[JonP]

The PE boxes have a full sized brace in the middle of the box. It's the thing seen here with the 2 big holes in it.

The triangle things in the corners aren't really braces, they hold the nuts so the front baffles can be removed. Most from scratch builders aren't making boxes with removable fronts so the triangles aren't needed.

I just finished a Modula MT pair, and used scratch built boxes.

I did a similar brace in the middle, though I cut out more holes. I did some smaller half and quarter circle cuts at the corners and sides to reduce some of the volume taken, while still leaving strength. It ended up sort of like a webbing of suspension. I'm planning on getting some pics online soon...

Basic concepts of bracing, you want to prevent the faces of the box from being able to vibrate. A large, unsupported panel acts like a drumhead, and if you put a solid piece of something between two sides, it prevents this. What it does, is divide the panel into two smaller ones, that vibrate with less energy at a higher frequency. You could use hardwood dowels, rectangular pieces of woood, or a full length/width piece. It is somewhat better to offset the brace a bit, to make two uneven sized panels, but that makes for more complex bracing. Depends on your box size and shape, sometimes horizontal shelf like pieces makes more sense, if you have a tall, narrow floorstanding speaker for instance. Look around at various designs, and do some reading in the books or on sites. You'll find lots of examples and explanations...

The PE box brace style hits the top, bottom, and both sides at one time. So, it's just a single board. Simpler, but you have to make both the length and width perfectly right so it fits well. Epoxy is a good gluing choice, it attaches well, and can make up for some gaps in the fitting, to really make sure you have a solid connection from the wall to the brace. The large holes are important, so you don't create walled off areas that would act as smaller resonant "sub boxes" of the full box size. That would mess with your expected tuning, and create other problems.

Hope that helps....

[technimac]

I just finished a Modula MT pair, and used scratch built boxes. ... you put a solid piece of something between two sides...(to)... divide the panel into two smaller ones, that vibrate with less energy at a higher frequency...

:agree:
I tried to follow that reasoning with the braces on my Modula MT's. The parts of the panels near the corners don't actually need bracing, so I cut them out to improve air flow within the cabinet and retain internal volume. Importantly, the middle of each panel is well-braced.

These are all the parts for a Modula MT before glueing. Actually the port tube has already been attached to the back and will act like another brace.



Here's a shot of the braces (original idea courtesy of Dan B) glued-up and ready for the sides, top and bottom to be assembled & clamped. My favorite glue for doing this is Henkel PL polyuethane, with its high viscosity, long working time and tendency to expand (filling voids and sealing inside corners).

[syzygylock]

Let's focus on what you're building, which is? Modula MT, minitowers, or what?

I am building a Modula MT. I was merely giving example of internal support being different across the same cabinet type builds. I'm sorry to have misled you ThomasW. Thanks for the pictures and advice everyone.

Thanks JonP, that's exactly what I was looking for. It's just that I don't see dimensions/drawings/placements for the internal support anywhere. And different pictures cause me confusions ops:.

Thanks everyone,