Just looking for a picture/description of the internal bracing of a subwoofer box, so I can get an example of how to do mine. Thanks
Hi Rocko,
I don't have pics but there are basically two type of braces. I will call them stick and panel. A stick brace is a piece of wood, let's say a 2X2 that you screw in place across any particular section.
A panel brace is one that is a piece of wood (panel) that fits tightly into the box and would act like a separator if it weren't for the holes cut in it.
Here's what came up when I googled internal subwoofer bracing. There are both types there.
http://images.google.ca/images?svnum=10&hl=en&lr=&q=internal+subwoofer+bracing&btnG=Search
I don't have pics but there are basically two type of braces. I will call them stick and panel. A stick brace is a piece of wood, let's say a 2X2 that you screw in place across any particular section.
A panel brace is one that is a piece of wood (panel) that fits tightly into the box and would act like a separator if it weren't for the holes cut in it.
Here's what came up when I googled internal subwoofer bracing. There are both types there.
http://images.google.ca/images?svnum=10&hl=en&lr=&q=internal+subwoofer+bracing&btnG=Search
For a 350L what kind of bracing would I need?Cal Weldon said:
It looks like they went a little overboard in those pics...
I think a more realistic goal for bracing is to make the panel resonance high enough so that it is not excited by subwoofer frequencies. Bracing raises the stiffness of the panels, and hence their resonant frequency. However get the wrong amount of bracing and you might have a resonance around the crossover frequency, which would make the sub easy to localise. The bracing scheme used on the old adire tempest ported designs was pretty reasonable to me. I don't have a source but i seem to remember adire recommending the minimum bracing spacing just be kept less than a certain amount (for subwoofers)
The most bang/buck is simple cross-bracing.
Use enough braces so that there's no more than 12" of unsupported 3/4" panel.
Use enough braces so that there's no more than 12" of unsupported 3/4" panel.
Can you kind of like just make a skeleton of the box out of 2 x 2 boards? Would that be sufficient bracing?
Square enclosures are typically not recommended as they tend to have resonance at single frequency (plus multiples of course). For subwoofers, usually, this fundamental is much higher than the passband so it's not much of an issue. When you build a 100 ft^3 sub enclosure, it would become relevant though 🙂
This is an inexpensive sub I built for a friend with minimal bracing. It has a single shelf brace and corner braces on every corner and cutout, and a magnet brace. It only weighs 138 lbs. And no, a cube box won't be a problem unless it is huge (you won't run into that problem often with subs), but lots of shelf bracing will take care of that as well.
Attachments
WOW! Nice link! I was worried I was OCD and my internal bracing was overkill!
I am building a 9cu.ft. (net) enclosure and using a Peavey 18" Low Rider driver, using Peaveys recommendations on enclosure and port diameter/length as guidelines. I have always heard and employed the notion more was better in previous projects with success.
I am aware this is intended primarily for sound reinforcement applications, but as a replacement for my old favorite build, a JBL B460 from years ago it will be a fun build and make an awesome sub and conversation piece.
"Strength of the completed enclosure has a great effect on the bass performance of the finished system. Internal bracing is required to improve the structural strength of the cabinet. Low Riders can generate enormous forces inside the enclosure, and panels that aren’t tiff enough will vibrate, if the cabinet panels are not stiff enough add more bracing." Peavey
I will post pictures if there is interest.
I find when talking about bracing overkill is just right.
One thing to consider when adding bracing is to cut the unsupported size of the walls to small sizes. That moves the wall resonance above the working range of the driver.
I will try and post some pics of my corner cabinets I built for JBL2245h 6th order.
One thing to consider when adding bracing is to cut the unsupported size of the walls to small sizes. That moves the wall resonance above the working range of the driver.
I will try and post some pics of my corner cabinets I built for JBL2245h 6th order.
That 2245h is an awesome driver, I had one in a 5 cu ft enclosure I built from JBL plans back in the day along with a BX63 crossover.
Have you found (or ever even needed) a recone kit that was decent? I looked and looked and never did...finally sold it.
I too love the 2245h, in fact my test system has 2 2245h, 2 2235h and 2 2206h with about 2000 watts of power. The 2245h is the reason I started testing different bracing designs. I found the more I braced it the more controlled the bass sounded. It's a shame JBL did away with that line, I have yet to find a driver that compares.
Re-coning kits, I have not found a full kit that works for me. Most of the kits out there use a stiff spider (d). I now put together my own kit (cone with surround, voice coil and I use a b spider). That combination seams to account for the loss of power of the magnet from age.
Re-coning kits, I have not found a full kit that works for me. Most of the kits out there use a stiff spider (d). I now put together my own kit (cone with surround, voice coil and I use a b spider). That combination seams to account for the loss of power of the magnet from age.
I have attached some pics of my sub cabinet build and my current test system. Yes it is overkill, but I had the stuff just laying around and wanted to see how far I could go and still have it sound good. It has went beyond what I thought it could.
Now I just need to finish my Pass A40 for the high end.
Now I just need to finish my Pass A40 for the high end.
Attachments
My first corner cabinet like this ended up 3db down at 17hz and that was measured with my LMS system. The 2 pictured here 1 22hz the other 24hz using a 6 inch port out the bottom of the cabinet.
I really wish I could have found another 2245h with the same specs as my first one. It still had good out put at 15hz and you could mess with the wife, to make her think there is an earth quake. Not that she was amused.
Sweet. I like the corner design. I see now why you say overkill is just right! What driver are you using in those? If there were decent recone kits for the 2245H I would still be using it, hard to beat vintage JBL.
Are those the 2245H/subs in the foreground....maybe a 5 cu ft cabinet??
So anyway, here is my latest effort still under construction. And this site always jacks up my pics, can anybody tell me why??
Senile in Nashville.
Attachments
Last edited:
- Status
- Not open for further replies.