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Discussion Starter #1
Hi I am a first time builder and I am looking to build, after port, driver & brace loss, a 12.6 ft 3 LLT tuned to 15hz. After running what I think is the right numbers in WinIsd I end up with a port velocity around 47m/s. Is that a high number or an accepted number. I am going to run it off an EP-2500 and put in a number of 850 watts. One last thing is it better to use the SDX 15 or move up to an IXL 18.4. Not too much to pick from here in Canada.Thanks in advance!!!
 

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I just checked and the SDX-15 actually has more displacement the IXL because of the extra 8mm xmax. I like the looks of the SDX better and I own one so it gets my vote.
 

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Discussion Starter #4
Thanks for the reply. I was reading another post on a build of a Mach 5 in a 350l box at 15hz and a few of the posts on it were concerened about the port not being the diameter of the port away from the wall. This may cause an unefficient port. Would I run into this with a 8in port, or would have a bigger issue with the port turbulence with the 6in?
 

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An 8 " port would probably need a bend, as Mike p. said the port is 41.75" long. You could also do a slot port too, or my favorite option would be to spend a few more dollars and get 2 18" passive radiators from CSS. PR's don't have any of the problems as ports, the only downside is the cost. You can also make a smaller box for the same tune with PR's.
 

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An 8" port would need to be 41.75" long as Mike P. said, so it might need a bend, or you could use a slot port, or my favorite option is using 2 18" passive radiators from CSS. PR's don't have any of the flaws that ports have, the only downside is the extra cost. PR's can also tune lower in smaller boxes. Here is an example of a SDX-15 in 8 cubic feet with 2 PR's in blue and a SDX-15 in 12.6 cubic feet tunes to 15 Hz with a port in yellow:



Not a huge difference in the FR and both can handle an EP2500 bridged, plus the box is much more manageable.
 

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An 8 inch diameter port 41.75 inches long will keep the port air speed to a maximum of 28 m/s at 13.5 hz. Ideally the port should be one diameter away from any wall. If it were only 4 inches away from a wall, I personally don't think it would be a big deal. As with many other things, less then optimum conditions still provides good performance.
 

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Discussion Starter #8
I think I will upsize my port to a 8" one. Looks like this will be a good change over from the six. What length do you think I should have to get a 15HZ tune. With a box like this will there be any need for a subsonic filter. I was thinking of the Reckhorn B-1 to go with the Ep-2500.
 

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Discussion Starter #10
An 8 inch port would need to be 42 inches long. With a 1000 watts input you exceed Xmax at 13.5 hz. Try the sub with the EP2500 first and see if you need the Reckhorn B1. No sense buying it until you know you need it.

Good point mike, Good to see another Sask. boy, I'm from Swift Current.
 

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Discussion Starter #12
I sure would like to get started on the box soon. Called around the other day to see who will cut the wood I want, and found a place that will. I want to do as much of this as I can however I only have a small table saw and think the 24" cuts will be hard to do on it. Is it best to go with the 8" port, I was wanting to stay with the 6" but if it will cause to much port noise I will change my plans. I see the SDX-15 has two 2ohm vc's. Would you run the EP-2500 bridged @ 4ohms or one side to a single 2 ohm vc? Thanks,
 

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Discussion Starter #15
I ordered my sub on Sat. from CSS. Hope to get it later this week, plan on cutting up some MDF on friday and get working on it on the weekend!!!!!
 

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I recently bought a SDX-15 and am very pleased with its low end performance. I am pushing it with my Behringer EP2500. I think you will be delighted with the quality of the SDX series. My box is approximately a 27.5" cube with an 8"X5" square port. Not sure if that is the best tuning but it does work really well for low end. Good luck
 

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Discussion Starter #18
Thats good to hear that the SDX and the Ep-2500 work well together. Sub should be here today and goin to get MDF around 2:00 pm. Hope to make some headway this weekend!!!!!
 

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Good luck. Hopefully you have more tools than I did. I actually ended up paying a place $60 to make all my cuts. I am a college student and my selection of tools does not include a table saw. More like a circular saw and a drill. Have fun and I hope it works out well for ya.
 

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Discussion Starter #20
Well I got the box made up and had a chance to listen to the sub untill both vc's went. Not too sure why they went. I was running one vc(2 ohms) to the ep-2500 and the the sub quit working so I pulled it out and the vc had 0 resistance. So I checked the wiring and the amp. All looked good. Within about 15min of a movie the other went as well. Now I am out. Big box ,no sub till I can get another. The settings on the EP-2500 are 1 on, 2 off, 3 on, 4 off, 5 off, 6 off, 7 off, 8 on, 9 off, 10 on. Line in on Input 1, Sub connected to Output 1. Any help would be great. Dont want to get another and have the same happen...:explode:
 
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