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post #1 of 17 Old 06-02-2013, 07:38 PM - Thread Starter
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Klipsch RW-12D

I just received the Klipsch subwoofer and of course it has the loose port tube. I am going to take it apart to fix that and while looking at some ideas on how to fix it I came across some posts about people making braces for their subwoofers internally. I am pretty crafty with wood and I am sure I can come up with something that will work with this subwoofer, my question us has anyone done it and seen an improvement? Or is it even worth it? I am already going to put in some polly-fill and taking care of the loose port issue. Should I just leave the bracing out of it?
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post #2 of 17 Old 06-02-2013, 07:57 PM
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An unbraced cabinet is a defective design. Just a single brace connecting the middle of two opposing panels will have the same stabilizing effect on those panels as doubling their thickness. As for poly-fill, a ported sub should be lined with an inch or two of damping, but it should not be filled with it.

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post #3 of 17 Old 06-02-2013, 08:10 PM - Thread Starter
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Thanks for the speedy reply Bill, so if I am able to brace the top to the bottom and the side to side with about a 2"x2" solid piece of wood this would be a good thing? No poly-fill? What would you recommend for damping instead of the polyfill? Could I use a spray on sound dampening material like dynamat spray or even the mat itself?
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post #4 of 17 Old 06-03-2013, 05:52 AM
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Originally Posted by cessna1466u View Post

Thanks for the speedy reply Bill, so if I am able to brace the top to the bottom and the side to side with about a 2"x2" solid piece of wood this would be a good thing? No poly-fill? What would you recommend for damping instead of the polyfill? Could I use a spray on sound dampening material like dynamat spray or even the mat itself?
Even a 1x1 is adequate, since there are no bending forces on the braces. If possible the baffle should be braced to the back as well. If the sub doesn't have any damping... also a defective design...line the cab with polyester batting or open cell foam, glued in place. Dynamat etc. works well in an enclosure that can't be braced, like a car door, but in a well braced cabinet doesn't add anything.

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post #5 of 17 Old 06-03-2013, 08:29 AM - Thread Starter
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Thanks Bill, I don't know if I can get a brace from front to back but I will try. As far as the batting, where I purchased the poly-fill they had poly-batting as well. Its a crafts store and I think its used for pillows and seat cushions. I will get some of that instead of the fill. Thank you.
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post #6 of 17 Old 06-03-2013, 08:42 AM
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Quick suggestion.. You can use Dowling for a brace and find it easier to place since your working from the outside in. Like Bill mentioned a 1”X 1” will make it much better than it is.

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post #7 of 17 Old 06-03-2013, 08:50 AM - Thread Starter
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Thanks Steve, I actually have some left over dowels from a cub scout project. I will check to see what size it is and how much I still have. Thanks again. Any suggestions on how to attach it. I plan on cutting it a little longer than the needed size and then just sanding it down until I can slide it in and using wood glue or is there other options to adhere it?
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post #8 of 17 Old 06-03-2013, 08:55 AM
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Quote:
Originally Posted by cessna1466u View Post

Thanks Steve, I actually have some left over dowels from a cub scout project. I will check to see what size it is and how much I still have. Thanks again. Any suggestions on how to attach it. I plan on cutting it a little longer than the needed size and then just sanding it down until I can slide it in and using wood glue or is there other options to adhere it?

Nope!.. that will work just fine as long as it's stout enouph. Wood glue is a good thing. smile.gif

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post #9 of 17 Old 06-03-2013, 10:15 AM
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Quote:
Originally Posted by cessna1466u View Post

I plan on cutting it a little longer than the needed size and then just sanding it down until I can slide it in and using wood glue or is there other options to adhere it?
Cut it about 1/8"-1/4" short. Get some small wooden wedges, used for installing windows and doors. Cut a small piece from a wedge, use it to wedge the brace in place, all surfaces well covered in glue.

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post #10 of 17 Old 06-03-2013, 10:33 AM - Thread Starter
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Thanks to both of you for this information. I will try it tonight and see how it comes it.
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post #11 of 17 Old 06-04-2013, 01:23 AM - Thread Starter
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I hope I didn't over do it. Apparently my woodworking skills are not that great. I cut the dowel pieces too small and ran out of dowels, so I ended up using my 2x2 pieces. I was not able to brace the front to back, there is just not enough room to get anything in there. The amplifier takes up a bunch of the back and the subwoofer the entire front almost. So I was able to get on from sided to side and 2 from top to bottom since I wanted one on each side of the port. Its probably not necessary but it makes me feel better. My worry is the batting. I used the poly batting as recommended and did almost all the surfaces except the back since the amplifier takes up most of it and there really isn't any exposed wood. I know subwoofers are designed to work in a certain amount of cubic space, I am concerned that I took up some of that cubic space by using the braces and the poly batting. Here are a few pictures, what do you think?



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post #12 of 17 Old 06-04-2013, 04:10 AM
 
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A suggestion would be to make sure about keeping the open nature of the amplifier, for air circulation purposes, clear. And at the front top, there's the LCD panel. I don't suspect there's a heat problem with the LCD panel but just the same, I left air circulation space below the LCD panel on the inside of the enclosure. I also made sure there was space next to the vent tube opening at the top of the box.

I didn't do any additional bracing. Why? It never occurred to me that additional bracing was necessary.
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post #13 of 17 Old 06-04-2013, 04:52 AM
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Quote:
Originally Posted by cessna1466u View Post

Klipsch RW-12D

I just received the Klipsch subwoofer and of course it has the loose port tube. I am going to take it apart to fix that and while looking at some ideas on how to fix it I came across some posts about people making braces for their subwoofers internally. I am pretty crafty with wood and I am sure I can come up with something that will work with this subwoofer, my question us has anyone done it and seen an improvement? Or is it even worth it? I am already going to put in some polly-fill and taking care of the loose port issue. Should I just leave the bracing out of it?

An enclosure has to be pretty small to not benefit from cross bracing.

When I build enclosures, I perform "rap testing" I give a robust knuckle rap to the the unsupported middle of large panels. If it resonates excessively, I add a 2x2 cross brace, shimmed and glued into place as Bill recommends.

It is possible to make 3/4" MDF boxes that almost seem like they are made out of concrete without too much work. Cross bracing is often skimped on in commercial products because adding it is labor intensive.

Semi OT anecdote:

Over a decade ago I built a 12" DVC subwoofer that seemed good enough for the purpose at the time. About 2 years I repurposed it as a subwoofer for a SR system and for the first time really put the driver through its paces. I upped the amplifier power from 400 watts to 2,000 watts. In actual use the amp often ran just below clipping or maybe even into a little clipping. The room went from 12' x 15' with a 9 foot ceiling to 120' x 45' with a 27 foot ceiling. Surprisingly enough the driver held together. However the enclosure experienced highly visible and audible flexing when driven hard. I added surprisingly small amounts of front-to-back bracing and tamed it back down. It ran at the edge of its performance limits weekly for almost 2 years.

One day I walked in and saw that it had been replaced, which was fine with me because it had been on the edge all along. I was never given any budgetary support for adding it or upgrading it so it was out of my hands. Nobody complained because I kept it just below its dynamic range limits. The system that replaced it had 2 18" drivers and was far larger. There was a funny story about how the bass player that had been detailed to replace it hooked up the new speaker with the same power amp and crossover settings and promptly just about blew the music director out of his office about 100 feet and several masonry walls away. It was about 12 dB more efficient and had good dynamic range reserves.

Eventually I decided to see what happened to the old subwoofer. Even though the bass player denied it under direct questioning, physical examination showed that it had ceased producing acoustical output. However, the problem was just an open connection in the internal wiring. The slings and arrows of trying to solder 12 gauge wire in the field with a 25 watt soldering iron. This time I came prepared with a 60 watt iron. It is still in service in a smaller room with a 400 watt amplifier and has plenty of dynamic range.
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post #14 of 17 Old 06-04-2013, 05:15 AM
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Quote:
Originally Posted by cessna1466u View Post

I am concerned that I took up some of that cubic space by using the braces and the poly batting. Here are a few pictures, what do you think?
Batting doesn't take up space. Adding it lowers the cabinet tuning a bit, which will compensate for the volume occupied by the braces.
Quote:
It is possible to make 3/4" MDF boxes that almost seem like they are made out of concrete without too much work. Cross bracing is often skimped on in commercial products because adding it is labor intensive.
+1. Commercial cabs are made thick and heavy not because that's the best way to do it, but because that's the least expensive way to do it.

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post #15 of 17 Old 06-04-2013, 05:51 AM
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Interesting story arny, that was a fun read.

Quote:
I was not able to brace the front to back, there is just not enough room to get anything in there. The amplifier takes up a bunch of the back and the subwoofer the entire front almost. So I was able to get on from sided to side and 2 from top to bottom since I wanted one on each side of the port. Its probably not necessary but it makes me feel better.


It’s going to help but ideally (not going to happen because of your situation) it would be nice to see the bracing in the middle of the enclosure. No way to do that because of the port.. well there is a way but it gets more complicated. To ad bracing that has a cutout for the port is impossible now that the sub is built. You would be very surprised to know of the many turnkey subs that are offered with no bracing at all. Some of them are big name or past big name subs.


Nice job..

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post #16 of 17 Old 06-06-2013, 09:51 PM - Thread Starter
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So the glue has dried, the subwoofer is put back together and I finally got a chance to sit tonight and listen to it. WOW! I can actually hear the difference. I am not saying that it now sounds like I have 2 subwoofers or all of a sudden my Klipsch sounds like a $5000 subwoofer but it sounds really good. No vibrations, no rattling and the bass seems to be hitting a little harder instead of boomy. I tested it with the begining of one of the Star Wars movies I forget which one but its when the spaceships are landing right at the beggining. It was amazing, I will say do that I still hear what I would describe as port noise, but I think its just becasue so much air is passing through. Thanks to all for the help, this was a great upgrade. I really appreciate it.
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post #17 of 17 Old 06-08-2013, 10:05 AM
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Yes, that is the only reason you'd hear port noise. Grab another at some point down the road and you'll likely loose or cut most of that out.

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