# Want to build new SDX 15 boxes need ideas



## Spudrunner (Oct 3, 2008)

So i have 2 SDX 15's now in sealed boxes for my home theater running off a EP2500.I am wanting to get more output from the subs if i can by changing the boxes to ported.The internal size of the boxes are 39''wide,14.750''deep,24.750''tall.So they are around 8 cubic feet with bracing.Here are some pics.I don't know if it is possible to add ports to the existing boxes or should i just build new ones.Thanks for any help.


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## lsiberian (Mar 24, 2009)

Your best bet is gonna be to rebuild the boxes. 

You need a 3 x 14 x 30" port to get a low enough port air velocity with your sub. It would be a very tough to do it right with current boxes.


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## Spudrunner (Oct 3, 2008)

So round ports would be out of the question?


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## tundraSQ (Mar 17, 2007)

lsiberian said:


> Your best bet is gonna be to rebuild the boxes.
> 
> You need a 3 x 14 x 30" port to get a low enough port air velocity with your sub. It would be a very tough to do it right with current boxes.


i was thinking something like this would work........but i agree...rebuilding in the long run would be easier and cleaner.


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## Spudrunner (Oct 3, 2008)

The only way i could reuse the boxes is if i could do round ports.To much bracing and everything is glued and biscuited.What kind of improvements can i expect with the ported box over the sealed box?


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## tundraSQ (Mar 17, 2007)

How much power are you giving these? Are you maxed out on excursion and output? Ported will be a noticeable increase in output obviously, but a pair of sealed 15's should be able to rock that room. 

Maybe upgrade to a pair of mal 18's....that would allow you to just cut new openings, and you should be able to sell the 15's.


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## Spudrunner (Oct 3, 2008)

I think the Behringer ep2500 puts out 600 watts per side.As far as selling the 15's getting something else,there is no budget for that right now.Just purchased some new Klipsch RB81 and a RC 64.Also have in the works a used Rotel 1066 or 1068 processor.So no extra now for new subs.Just have some cash for new boxes.


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## tundraSQ (Mar 17, 2007)

Spudrunner said:


> I think the Behringer ep2500 puts out 600 watts per side.As far as selling the 15's getting something else,there is no budget for that right now.Just purchased some new Klipsch RB81 and a RC 64.Also have in the works a used Rotel 1066 or 1068 processor.So no extra now for new subs.Just have some cash for new boxes.


save up for a second ep2500...or find a way to double that power.


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## Mike P. (Apr 6, 2007)

Your wood work is gorgeous!



> So round ports would be out of the question?


No. Each sub is getting 650 watts from the EP2500, if you tune the box to 20 hz and use a Hi-Pass filter at 13 hz, the maximum port air speed would be 30 m/s, not a problem for a 6" diameter flared port 20 " long.





























http://www.parts-express.com/pe/showdetl.cfm?Partnumber=268-354

Here's the difference in output comparing sealed to ported. You would be gaining 5-7 db.









Mounting the port on the front of the cabinet would require the use of an elbow due to the lack of front to back depth. The cheapest solution is to use a 6" diameter schedule 40 PVC elbow. The total length of tube and elbow needs to be 20" as measured through the center. The elbows are fairly heavy and would need to be supported by a block of wood between the elbow and the bottom of the cabinet. You can see an example of 4" PVC elbows that I used in one of my builds.

http://www.hometheatershack.com/for...rojects/8554-mach-5-audio-ixl-18-4-build.html

On the 4" elbows that I used the port tube was a smidgen loose in the elbow, I put one wrap of black electrical tape around the tube before inserting it into the elbow. Then I hot glued around the perimeter of the connection. I have been torturing these subs for two and a half years now with no problems.


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## Spudrunner (Oct 3, 2008)

Thanks for the wood working compliments.
That graph was what i was wanting to see.I am for sure going to do a ported box.So a 20'' long 6'' port is what i need for the size box i have now?Flared port.


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## Mike P. (Apr 6, 2007)

Yes, add a 6" diameter flared port to the box you have now and you're done.


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## Spudrunner (Oct 3, 2008)

I wonder if there is any suppliers of them 6'' flared ports in Canada?I will have to do a search.Thanks alot for the info.If i would have known how much more out put the ported box would give i would have built them first.


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## Spudrunner (Oct 3, 2008)

That was easy.Creative sells them ports.


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## Spudrunner (Oct 3, 2008)

What would be a good hi pass filter to get?


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## Mike P. (Apr 6, 2007)

> If i would have known how much more out put the ported box would give i would have built them first.


You should find a source for the schedule 40 PVC elbows before you do anything. I'm not sure what the price is or the availability.

Modifying what you have should be fairly easy since your bracing runs front to back. Just keep the intake flared end 6" away from the back cabinet wall.


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## Spudrunner (Oct 3, 2008)

Phoned the local hardware store today and they have stock on the elbows.Will pick them up later this week and hope fully order the 6" flared ports to.


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## favelle (Jan 19, 2009)

Wow, the output difference on that ported is just crazy. It like "free" power!


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## Mike P. (Apr 6, 2007)

> What would be a good hi pass filter to get?


The Reckhorn B2 from CSS



> Wow, the output difference on that ported is just crazy. It like "free" power!


A rule of thumb is it takes 2 sealed subs to match the low end out put of one ported sub. All my subs arer ported, I love bass!


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## Spudrunner (Oct 3, 2008)

The more i think about porting my boxes the more excited i get about it.Bass is goooooooooooooooooooood.:TI need to get more bass as well because i getting rid of my old tower speakers that had 10" subs and 200 watt amps built into each cabinet.Don't think i can do it for a couple of weeks though cause it looks like i am buying a used Rotel surround processor.Gonna get rid of my old HK 320.Hope fully my new Klipsch speakers will be here this week end as well.


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## scotthulbs (Jan 11, 2009)

Update?


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## Spudrunner (Oct 3, 2008)

Nothing to update yet.I haven't had a chance to get the ports yet.Some other things came up.I did get my new Klipsch speakers and a Rotel processor though.With that new processor it has changed the way the subs sound.It is alot better but i am still going to port the boxes.


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## scotthulbs (Jan 11, 2009)

Looking really good! How you liking the Klipsch fronts. I have been talking myself out of upgrading to the same center for quite a while. I know if I pull the trigger on the center, I will end up with matching towers and surrounds.


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## Spudrunner (Oct 3, 2008)

I am for sure enjoying them but not as much as i should be but just because i have been busy lately.If you do get the center you will for sure be buying the fronts as well.I also really want to get the surrounds but funds right now are not letting me.


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