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This is debateable, but mostly true and I would agree. However if the first three words of your sentence are removed it becomes un-true.
Maybe more important would be to define 'overall' ? And hence the reverse must be true...Driver for driver you can't submit a ported design that outperforms sealed.......overall of course!

Sonny...you already know my opinion...seal em up!!!!! Four individual boxes properly placed around the space for a smoother in room response. Have you gotten a chance to read any of Earl Geddes recent papers on the subject? Really interesting observations and results.
 

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Sorry Sonnie. My fault :doh:

Let's get back on track with Sonnie's build here and not turn this into another mind numbing sealed versus ported debate.
 

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So what are the options?

2 LLT
4 Sealed
4 IB

Correct? And this is all at one single location? If so, I choose IB, using the FI IB18's.

If IB is not an option, I like the 2, Q18 LLT idea.

As for the 4 sealed spread throughout the room, the picture on page 2 shows two subs (LLT's) up front already. If that's already there, I say duplicate those. If that's just a what-I-want-but-don't-currently-have type of picture, then I still say duplicate them (4 of the same subs) and will be all for either 4 LLT's or 4 sealed Mal-X's
 

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Discussion Starter #64
Yes... there are two AudioPulse Axis 15's in the from powered by a pair of EP2500's and tuned to 17Hz.

For this build the location, number of drivers and type of driver is already settled on.

  • 4 Exodus Maelstrom-X (short of Kevin telling me it will be over a month before restocking at the time I get ready for them).
  • EP2500
  • LLT
  • From 10-150ft^3
  • All in the rear riser.
The only decision left is what size enclosure and what tune to go with?

Here are some various models...

 

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Sonnie, as you already know, integrating subs in different locations is key; Setting the delay, EQ ect. Integrating different subs in different locations will be even harder, but by no means impossible. I think I've forgotten, but do you have a DCX-2496? With 6 subs and it's 6 outputs, along with EQ, delay, ect... it'll be well worth the money to get one!

Now, for my .02. Since you're going with 4 Mal-X's in an LLT, you will have PLENTY of output, especially with the Axis twins upfront. That said, I would go with the largest and lowest tuned option possible. Sure, it will decrease your output in the 15-45hz area, but you have FOUR 18's! That will not be a problem.

What it will gain you is more extension and also a little more protection due to the very low tuning. Because of that low low tuning (10-12hz) I don't see a need for a subsonic filter. You'd only start running into problems 1/2 octave below tuning, and how much content is there in the single digits and also, how much power will you be giving each driver? It's not like you'll be pusing 6-800w of power (per driver) during the WOTW scene right?
 

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Are you planning on using filters, cause it still looks like your models are using a highpass. Really not needed - non value added.

Were it me, assuming the driver's parameters haven't changed from the first iteration, I like the looks of four discrete subs, each ~17 cubes with an 8" diameter port that is ~36" long for ~13.8hz tuning. Yes, tons of displacement on hand in which case I'd usually suggest a lower tune, but considering your subs up front are tuned to 17hz, not much point in going too terribly lower with these.
 

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Discussion Starter #67
Sonnie, as you already know, integrating subs in different locations is key; Setting the delay, EQ ect. Integrating different subs in different locations will be even harder, but by no means impossible. I think I've forgotten, but do you have a DCX-2496? With 6 subs and it's 6 outputs, along with EQ, delay, ect... it'll be well worth the money to get one!

Now, for my .02. Since you're going with 4 Mal-X's in an LLT, you will have PLENTY of output, especially with the Axis twins upfront. That said, I would go with the largest and lowest tuned option possible. Sure, it will decrease your output in the 15-45hz area, but you have FOUR 18's! That will not be a problem.

What it will gain you is more extension and also a little more protection due to the very low tuning. Because of that low low tuning (10-12hz) I don't see a need for a subsonic filter. You'd only start running into problems 1/2 octave below tuning, and how much content is there in the single digits and also, how much power will you be giving each driver? It's not like you'll be pusing 6-800w of power (per driver) during the WOTW scene right?
I had basically this same setup with my last HT room... two subs in front corners, two subs in the rear center... with main listening position equidistant from each. No phase problems, no delay problems, hardly any response problems. It was painless to setup, although it was not without LOTS of experimenting to make sure all worked well. I anticipate basically the same results with this setup, except a LOT more woofin' goin' on. :flex:

These will be getting more like about 450-475 max power each, so it should not be too serious of a risk.

Are you planning on using filters, cause it still looks like your models are using a highpass. Really not needed - non value added.

Were it me, assuming the driver's parameters haven't changed from the first iteration, I like the looks of four discrete subs, each ~17 cubes with an 8" diameter port that is ~36" long for ~13.8hz tuning. Yes, tons of displacement on hand in which case I'd usually suggest a lower tune, but considering your subs up front are tuned to 17hz, not much point in going too terribly lower with these.
Yeah... those are with 10Hz HPF's... just being cautious. I will probably still run one at 5Hz. The added value might be a slight decrease in distortion.

What would be the benefit of using four discrete subs vs. one enclosure with four subs, which will be much easier to build? They model the same.
 

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Discussion Starter #69
Location still won't be flexible with discrete subs. The location will still be in the riser, just each sub will be sealed off from the other instead of using one larger enclosure.

I will post a floor design of the riser framing once I get to the office. I designed it at the office and did not copy it to my home laptop.
 

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I like Steve's suggestion of 80ft total, 20ft per driver. Tune them to 13hz with a pair of 12" x 36" ports:scared:. :dumbcrazy:. Plug a port (basketball wrapped in a towel maybe?) and drop the tune to 9.1hz :hsd:.

Really anything around the 80ft-90ft size, with 12-14hz tuning is going to be a winner.
 

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Hey Sonnie, have you come across any information on dual bass arrays? Your design is pretty close to the premise. It seems to be a new concept across the pond gaining a lot of respect. What i gather is near equal forces facing eachother from the front and back of the room on the same plain. I've seen some posted FR graphs and they re the smoothest i've ever seen!
 

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Discussion Starter #73
I have not seen anything on it, however, I know that in my last room, having nearly the same in front and rear gave me the smoothest response I ever had without eq'ing.
 

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Sonnie said:
The location will still be in the riser, just each sub will be sealed off from the other instead of using one larger enclosure.
Ricci said:
20ft per driver. Tune them to 13hz with a pair of 12" x 36" ports
Should work nicely.

mayhem said:
Hey Sonnie, have you come across any information on dual bass arrays?
The biggest issue with this type of design is that you forfeit half of your total headroom. Fine if you are using somewhat inexpensive drivers, but if he is going with quad Maelstroms and wants to get the most out of them, I would avoid this implementation. Achieving a relatively flat FR isn't all that difficult.
 

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Steve...Could you expain the loss of headroom? Are we talking about phase cancellations or something else? Besides the low distortion of the Ported alignment and abundant output, what's left to achieve other than smooooth low FR?
 

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Are you set on the EP2500's? They now have an EP4000 that's not that much more expensive. Pre-order going on now here. I'm drooling over this amp and it's a great price.
 

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Discussion Starter #78
Getting a bit more done now. I have settled on 4 Q18's and a pair of EP2500's.

These are going to work out better since Scott can design them as needed. They will be single 2 ohm run parallel.



 

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Discussion Starter #79
Preventing cavities from resonating...

I have been thinking about this riser and the large cavity inside. Of course it will be an actual sub enclosure, but I cannot help but to wonder am I going to have a large resonating cavity of sorts.

Here are a couple of pics to help understand just how big the cavity is... of course it is in sections, but still a LOT of hollow space.





Anyone have any ideas of what I might be facing and any way of helping to assure I don't run into issues?

Thanks!
 

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Discussion Starter #80
Re: Preventing cavities from resonating...

To clarify... the bluish shaded area is already filled with sand and the pinkish area is already filled with cellulose insulation... THOSE areas are obviously not part of the sub enclosure.

 
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