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Discussion Starter · #1 ·
I have a 15'' re xxx on the way. Talked to a tech and he recommends 4.5cf ported enclosure for ht use. He is supposed to send me some enclosure specs via email.


Looking for good output down to 20hz or a little lower. This will be my first ported enclosure.


Any other enclosure ideas?


Here are the specs on the driver.




15"

Electrical Q Value -Qes: 0.58

Mechanical Q Value -Qms: 3.62

Total Speaker Q Value -Qts: 0.501

Free Air Resonance -Fs: 19.10 Hz

Equivalent Compliance -Vas: 207.0 liters

One-Way, Linear Excursion -Xmax: 54 mm

Efficiency -SPL 1W/1m: 85.81 dB SPL

Effective Piston Area -Sd: 810 cm^2

DC Resistance -Re: 4.2 ohm

Nominal Impedance -Znom: Dual 2 ohm

Thermal Power Handling -Pe: 2000 W

Force Factor -Bl: 18.16
 

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You are talking about the split coil version right? Ummm 4.5cu ft ported for HT = Epic fail with this driver.
That's about right for a sealed cab for it. If looking for response to just 20hz range just skip ported altogether and go for 5 or 6 cu ft sealed with this driver. ported is a bit worthless for these unless you are tuning well below 20hz.


Try a 16cu ft (450L) net enclosure tuned to 13.5hz with an 8" x 40.5" heavily flared port. Buy a Crown CE4000 and bridge it into it. This will rock some HT bass.
 

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Discussion Starter · #4 ·
I don't want a box the size of a refrigerator.
What is some good modeling software that i can download?


5-6cf is about as large as i want to make the inclosure. I wan't good bass up to 80hz, as this is where it will be crossed over with my mains.


Do you lose some of the upper bass with super low tuning. I also wan't this to sound good on music as well.
 

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You can download WinISD or Unibox if you have excel or an emulator. If your box size is limited to 5 or 6 cu ft and you are concerned about SQ ust seal it and get a BIG amp. You don't lose your upper bass output by tuning low. Maybe 2 or 3db at the absolute most, but i don't consider that of much concern when you are picking up 15db at lower freq's. These subs need huge ports and low tuning + a lot of airspace to do their thing ported. They do really well sealed due to the massive displacement and they naturally get low.
 

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Discussion Starter · #7 ·
I have 4k watts on hand and an sms-1 for eq duties. I know you are experimenting with an 18'' xxx in a sealed box. How is that working out?





Quote:
Originally Posted by Ricci /forum/post/16908643


You can download WinISD or Unibox if you have excel or an emulator. If your box size is limited to 5 or 6 cu ft and you are concerned about SQ ust seal it and get a BIG amp. You don't lose your upper bass output by tuning low. Maybe 2 or 3db at the absolute most, but i don't consider that of much concern when you are picking up 15db at lower freq's. These subs need huge ports and low tuning + a lot of airspace to do their thing ported. They do really well sealed due to the massive displacement and they naturally get low.
 

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build a tall box with the port(s) running vertically.


such high output drivers are best suited to passive radiators but if you can only manage a port it has to be large.


you're not quite as screwed as you would be if you went with a 18" version but you are still going to need a rather unconventional enclosure to make it work right.


this driver likes very big enclosures.


a smaller enclosure would work in a sealed alignment but you would lose half the output.


don't build anything until you consult us on the port design you will be using. with so much airflow you will need to take steps to ensure it doesn't make farting sounds.
 

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Discussion Starter · #9 ·
I don't have the space for a big ported enclosure right now. All my gear is in a small room due to a divorce. I will have a nice sized dedicated room after i move again next year.


So i guess ported is out for know. How many cf will it take for a good sealed enclosure. I'm new at modeling subs at the moment.


I have plenty of power and eq.
 

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It's a little bit more than experimenting. I'll have 4 of them in 9cu ft each soon, but I've been running one sealed for well over a year and it's been to 2 SW GTG's and I've been running another one along with the first in a slightly smaller sealed box for a few months. Sealed isn't as dumb as the ported ones output but that thing is 25cu ft. I can fit 3 sealed ones in the same amount of space and they'll overpower it.


Anyway, play around with the simulations and see what you get. I'm not saying that you can't port one in 5.5cu ft but it won't be easy to get it to be balanced. I modeled one at 5.5 cu ft tuned to 22hz and it had more to go even at 4000w input, which is essentially leaving extension and output on the table. The response is a bit humped up around 30hz. The vent itself was an 8" x 55.5" long and it would still be overloaded and would have bad resonance issues. It also takes up about 1.65cu ft itself. I would not use any less than an 8" vent with that driver. Dual 18" PR's in 6cu ft may be worth a shot. The enclosure would be much smaller and you wouldn't have to worry about trying to fit a vent in there. Try modeling some of those up.


If you run it sealed just go with 5 cu ft and you should be fine with up to 3200w input all the way down into the single digits.


What amp you runnin?
 

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Discussion Starter · #11 ·
Amp is a qsc rmx 4050hd. 4k watts bridged into 4 ohms.




Quote:
Originally Posted by Ricci /forum/post/16909335


It's a little bit more than experimenting. I'll have 4 of them in 9cu ft each soon, but I've been running one sealed for well over a year and it's been to 2 SW GTG's and I've been running another one along with the first in a slightly smaller sealed box for a few months. Sealed isn't as dumb as the ported ones output but that thing is 25cu ft. I can fit 3 sealed ones in the same amount of space and they'll overpower it.


Anyway, play around with the simulations and see what you get. I'm not saying that you can't port one in 5.5cu ft but it won't be easy to get it to be balanced. I modeled one at 5.5 cu ft tuned to 22hz and it had more to go even at 4000w input, which is essentially leaving extension and output on the table. The response is a bit humped up around 30hz. The vent itself was an 8" x 55.5" long and it would still be overloaded and would have bad resonance issues. It also takes up about 1.65cu ft itself. I would not use any less than an 8" vent with that driver. Dual 18" PR's in 6cu ft may be worth a shot. The enclosure would be much smaller and you wouldn't have to worry about trying to fit a vent in there. Try modeling some of those up.


If you run it sealed just go with 5 cu ft and you should be fine with up to 3200w input all the way down into the single digits.


What amp you runnin?
 

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Quote:
Originally Posted by jeff76 /forum/post/16909444


Amp is a qsc rmx 4050hd. 4k watts bridged into 4 ohms.

Eeeeewwww.... That's what I'm talking about.
Heck you could add another 15 later on with that bad boy.


I did a little PR modeling and it doesn't look too bad. Could you swing about 8.5cu ft with 2 18" PR's? That'll be tuned near to 15.5hz and the response looks good. The driver will still be below xmax in the passband down to 14hz even with the full 4kw ( you'll probably smoke a coil if you sustain that kind of power for too long though, but I've been ok so far. It'll be great for peaks.) The PR's don't fare so well though with 83mm of one way excursion at tune at that power level. Might be concerned with that if you push it too hard and the content hits just right. If you knock the power back to a more realistic 1000w the PR's excursion is in check at the tune.
 

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Discussion Starter · #14 ·
I did some measuring. I have about 5.5cf or 150 litres to work with. This will just be a temp. box till i move into a bigger place. I modeled a 150l, 200l, and 250l box on win isd.


There wasn't much difference between the 3. If i was doing everything correctly.
 

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Discussion Starter · #16 ·
I'm going sealed for know but thinking about a ported box in the future after i relocate. It got me thinking though. The ported box is so damn big i will have minimal placement choices even after i move.


I could build two sealed enclosures in roughly half the space of one ported box. This would give me more flexibility and definitly more output than a single ported enclosure.


Yes it will be more expensive but i already have the amps. I'll just have to buy another driver.
 

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Quote:
Originally Posted by jeff76 /forum/post/16911217


I'm going sealed for know but thinking about a ported box in the future after i relocate. It got me thinking though. The ported box is so damn big i will have minimal placement choices even after i move.


I could build two sealed enclosures in roughly half the space of one ported box. This would give me more flexibility and definitly more output than a single ported enclosure.


Yes it will be more expensive but i already have the amps. I'll just have to buy another driver.

yes getting same output from smaller boxes takes $$$ ( and EQ ).


you can become even more space efficient by switching from XXX drivers to LMS drivers again for extra $$$.
 

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Quote:
Originally Posted by vasyachkin /forum/post/16912344


yes getting same output from smaller boxes takes $$$ ( and EQ ).


you can become even more space efficient by switching from XXX drivers to LMS drivers again for extra $$$.

This is where I'm at. multiple sealed takes a lot of more money than just slapping any 2 big 18's in ported missile silos, but I think that the end result will be better and more flexible. I still like the XXX better than the LMS for HT duty (better natural extension, more powerful lows, more rugged) LMS is the better performing driver all around though (smaller box, better top end, higher thermal power handling). Too bad the 09's will likely be $1500ea.
 

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Discussion Starter · #19 ·
I originally wanted to go with a pair of lms 15's. But they are not available right now. I got a great deal on a used xxx 15'' so i decided to try it. If im happy with it i will shop for another used one in the future.


The lms may be better overall but they are $$$ and you can't find them on the used market. I should have the driver next week. I'll put some pics up when i receive it. Box will be solid but nothing fancy, as it well be experimental.
 
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