Should I go ported or sealed? - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 6 Old 12-06-2019, 07:17 PM - Thread Starter
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Should I go ported or sealed?

Hey guys,

Im looking for some opinions on a subwoofer setup I am about to build to fit in a custom Entertainment Center that is nearing completion. Here's the deal:

I initially did the equipment purchasing and box design a year ago and based on my research in the forums and some info from LTD02, I decided to build a ported subwoofer box with a single UM18-22. I did the modeling in WinISD and thought I was settled on the design. The plan was/is to tune it to 19Hz, and run a filter from 10-80Hz, with two additional sealed subs housing one PA460 each filtered at 80-200Hz.

Fast forward a year and now that I have built the Entertainment Center and am ready to build the boxes (yes it took me an entire year, lol) I went back into WinISD to look at the files and starting playing around. Now I wonder if I would be better to go with two UM18-22s in a sealed configuration. The transition seems to be smoother to the PA460s in the graph although I lose a little bit around the port tune. Although at the maximum SPLs its modeling I don't know that it would matter.

I have attached some screenshots. The large wood veneered area in the bottom center will be the UM18 box. The two PA460 subs will be on the ends facing sideways. You'll notice the box is bigger in the sealed models because of not having a port. I have modeled the signal power at 75% of the woofers RMS rating.

Should I continue down the ported road and gain a little more low end at the port frequency, and deal with what I assume will be more possible tweaking/tuning with the mixture of ported and sealed, or should I add another UM18 and keep everything simple and sealed? I have already purchased a Crown XLS2502 (775Wx2 @4ohm s) that I can use to power the one ported UM18, the two sealed UM18s, or the PA460's. I still have to buy an additional amp. Also, any thoughts on the crossover points?

Thanks
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post #2 of 6 Old 12-07-2019, 05:30 AM
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you may wish to cross your pa460's a little lower. then combined with one big ported sub, which will maximize output around the tuning frequency, you get the most output without having to buy any more gear.







big ported tuned to around 16-18hz.

low pass 4th order around 50hz.

pa460's sealed. 3 cu ft each.

high passed at 25hz 6th order to pull phase into alignment.
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post #3 of 6 Old 12-07-2019, 08:07 AM - Thread Starter
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Quote:
Originally Posted by LTD02 View Post
you may wish to cross your pa460's a little lower. then combined with one big ported sub, which will maximize output around the tuning frequency, you get the most output without having to buy any more gear.







big ported tuned to around 16-18hz.

low pass 4th order around 50hz.

pa460's sealed. 3 cu ft each.

high passed at 25hz 6th order to pull phase into alignment.
Hi LTD02, thanks for the reply. I can't seem to come up with the same graphs that you do. I am attaching the changes you told me to make. What am I missing?

Also, would you still go this route over the all sealed option if money (additional equipment) was of no consequence?

Thanks
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post #4 of 6 Old 12-07-2019, 08:36 AM
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Ive only built 6 diy subs with 3 different builds so take this Advice for what you paid for it but... I really like the sealed sound better. It could have been due to a number of error factors but I’ve built 2 ported box builds, rebuilt one to sealed and then plugged off another and got a driver that fit the cuft for the sealed config. I like the sound way better on both. Like I said, a lot of factors could be the case for this...

Also, I love the smaller box requirement. I have some downfiring 13x13x13 cube 12” Dayton HO’s they look darn slick and sound amazing!

Edit: I probably should update my signature
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post #5 of 6 Old 12-07-2019, 04:27 PM
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I agree, you should tune the PA-460's closer to 40-50hz, 80hz is too high.

As for sealed/ported. If you goal is 1-10hz, then go sealed. Otherwise go ported.

If all you need is >15hz, then 2 or 4 UM-18's in 15hz ported boxes should be sufficient for most rooms/people.

If your goal is 1-10hz sealed, then you'd probably want to add as many sealed UM-18's as you can, possibly dual-opposed.
Infrasonics knows no bounds, you need to throw all the drivers you can afford to accommodate at the problem.
8 UM-18's would be a good-start if that is truly your goal.
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post #6 of 6 Old 12-14-2019, 07:27 PM
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Quote:
Originally Posted by TStubb View Post
Hi LTD02, thanks for the reply. I can't seem to come up with the same graphs that you do. I am attaching the changes you told me to make. What am I missing?

Also, would you still go this route over the all sealed option if money (additional equipment) was of no consequence?

Thanks
looks pretty good. looks like you may need to increase the level of the um18's or reduce the level of the pa460's.

i used 99 volts on the um18 which is the output level peak of behringer nx6000 or nx3000 bridged. then i adjusted the 460's to match.

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