What to do with four 15" RSS390HF subs and 2 Crown XLS1000

2441 Views 12 Replies 2 Participants Last post by Mike P., Apr 16, 2014

Bullitt5094

Discussion Starter · Apr 15, 2014 (Edited)

As the title says, I'm wide open on recommendations on what to do with four 15" RSS390HF subs and 2 Crown XLS1000s. This will be for my HT plus I would like some clean output to minimally augment the very low end of my B&W 804s for music. But mainly these are for LFE output since the B&Ws need very little help for Stereo. I also have a FBQ-2496 Feedback Destroyer if I need to do a High Pass for a ported design or equalization above and beyond what my Denon AVR-4520 is capable of.

I would like a maximum of two boxes, each box having an exterior dimension of no more than 24"x24"x36" give or take a few inches. Not opposed to any configuration suggestions. Basically wide open for ideas from the community.

The room is configured with bass traps and acoustic treatment. Approx room dimensions are 20 deep, 15 wide and 9ft ceiling.

My first inclination is two Dual Opposed Sealed boxes as big as I can make them, but again, I am wide-open minded at this point and kind of excited as to what the suggestions will be.

onder:

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Mike P.

· #2 · Apr 15, 2014

This is the estimated SPL of a single dual sealed cabinet compared to single dual ported cabinet in the size you stated.

Just making sure these are HF drivers and not the HO drivers, correct?

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Bullitt5094

Discussion Starter · #3 · Apr 15, 2014

First, yes, these are HF not HO subs.

So there are two plusses with the dual-sealed configuration. First, it's output is better in the sub-20hz range, which is what we all look for. Also, I won't have stupid cone movement below the tuning of the port so I won't need to implement a high pass filter. Am I reading between the lines correctly?

Is there any advantage with going with a ported enclosure with my configuration and size limitation.

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Mike P.

· #4 · Apr 15, 2014

Above 15 hz the ported is superior in output, below 15 hz there isn't much happening in movies. What is the lowest frequency the FBQ-2496 Feedback Destroyer can st a HPF at?

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Bullitt5094

Discussion Starter · #5 · Apr 15, 2014 (Edited)

20Hz. Not good. And it's a parametric equalizer, not a HP filter, apparently. I thought it had a HP function too, but it doesn't. I also have the Denon 4520 but I really don't see a way to set a hard, high slope HP in it either unless the Audigy does it automatically.

What filter/hardware would you suggest I use with the Dual Ported configuration? The Crown has a HP filter but it's minimum is 40hz. I assume I need a pretty sharp filter set around 15 hz for that configuration?

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Mike P.

· #6 · Apr 15, 2014

Ill model it again tonight when I get off work and we'll see what you need.

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Mike P.

· #7 · Apr 16, 2014

Modeling with a HPF at 20 hz looks the same as the graph in the post above. Ported would have a 4 to 5 db advantage over sealed.

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Bullitt5094

Discussion Starter · #8 · Apr 16, 2014

Thanks. I'll mull over the results and decide which way I want to take it.

If I do two of the dual opposed, is there a disadvantage mounting the speakers on the big sides of the box instead of the "ends" of the box? I.E. having the drivers mounted on two opposite 24" x 36" sides instead of the 24" x 24" ends?
Another question... if properly braced internally, will the sealed enclosure be OK made out of 3/4" MDF as opposed to hardwood ply?
Lastly, with the ported enclosure, is there any sonic or SPL advantage using a baffle port vs a tube port?

If this is too much of a brain drain I'm sure all these answers are in these threads somewhere if I search hard enough. Some quick replys would really save some time if you could take a few minutes to clue me in from your experience.

Thanks!!

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Mike P.

· #9 · Apr 16, 2014

If I do two of the dual opposed, is there a disadvantage mounting the speakers on the big sides of the box instead of the "ends" of the box? I.E. having the drivers mounted on two opposite 24" x 36" sides instead of the 24" x 24" ends?

As long as the rear sub is away from the back wall there will be no problem.

Another question... if properly braced internally, will the sealed enclosure be OK made out of 3/4" MDF as opposed to hardwood ply?

If properly braced 3/4 is fine.

Lastly, with the ported enclosure, is there any sonic or SPL advantage using a baffle port vs a tube port?

There is no difference as long as the port air speed is within acceptable limits.

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Bullitt5094

Discussion Starter · #10 · Apr 16, 2014

3/4" MDF is OK. I don't need to use Ply?

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Mike P.

· #11 · Apr 16, 2014

MDF is fine. If you use plywood it has to be the void free type.

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Bullitt5094

Discussion Starter · #12 · Apr 16, 2014

I much prefer MDF. Thanks again. I REALLY appreciate your help and advice. Whatever I start building I'll post on the forum as a build thread.

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Mike P.

· #13 · Apr 16, 2014

Looking forward to it. :T

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