# CSS SDX10 X 4! What to build?



## jroc (Feb 1, 2010)

I have 4 - SDX10's that are currently in a single sealed box (separate air space) below my screen area in my h/t. 

My wife is not that happy with the size of it so here's a chance for me to improve on the design, and build something new.

I can either build 4 separate smaller boxes or go duals. Since I've already tried the sealed route, maybe I'd try ported, or maybe dual opposed?

I'm driving them all at 4 ohm bridged into a Yamaha P2500S (GREAT amp btw..)

Anyways I'm looking for some new ideas! I like the dual opposed idea, but not very familiar.

Thx!


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## GranteedEV (Aug 8, 2010)

I think four separate 1 cu ft sealed boxes will work best! If i were going vented i'd go with a 36" x 4" port which i doubt would fit in a small vented box.

How exactly did you get a nominal 4 ohm load? series-parallel? why not just run them in parallel stereo 2 ohm mode? What do you gain by bridging?

Is that amp even 2 ohm / 4 ohm bridged stable?


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## jroc (Feb 1, 2010)

I'm running the amp in 4 ohm bridged mode - I wired them series/parallel to 4 ohms. That amp is stable to 2 ohms producing 650W per side or 1300w bridged 4ohm. I have a y cable from my sub out on my receiver which goes to my Samson S-Convert box. I have another sub running to another amp so running the Yammy in bridged mode saves me from using another y adapter.

I agree that 4 individual boxes would give me the most flexibility in placement of the subs.I could run 2 per side under my L/R front speakers and see how that sounds. That's definitely one option.


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## mdrake (Jan 31, 2008)

Personally I think the 4 sealed enclosures is the way to go. :T I think it will give you the best room response if they are placed correctly. 

Matt


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## Binary (Nov 23, 2009)

4x small sealed, and invest in something like a SMS-1 or a DSpeaker. EQed subs are just plain better. Youve got plenty of power to eq some extension outta the 4 drivers. Smallest boxes, best compromise on sound quality, and even response from having 4 separates.


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## jroc (Feb 1, 2010)

Sounds good - should I am for a QTC of .7? or so?


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## GranteedEV (Aug 8, 2010)

jroc said:


> Sounds good - should I am for a QTC of .7? or so?


A qtc of .7 is really popular and you probably can't go wrong with it.

I personally like a qtc around .6 / a bessel alignment probably if you factor in stuffing ... it gives you less power handling (excursion is easier) but further reduces distortion like ringing etc... It also has a bit smoother extension.


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## Mike P. (Apr 6, 2007)

A 1 cu.ft. box would have a Q of .67 and four 13.5" cubes should be easy to integrate.


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## jroc (Feb 1, 2010)

Yes that would be great. Thanks for the help. How much polyfill should I loosely stuff? Half? Full?


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## Mike P. (Apr 6, 2007)

One pound per cubic foot of box volume will give you a 10% increase in box volume, not worth it for such a small cabinet in my opinion.


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## Binary (Nov 23, 2009)

generally speaking with fiber-fill, you can get about an extra 15-30% net enclosure volume if you stuff it with about 1 lb/cu ft. And i'd highly recommend it, 15% is enough to push you to that qtc of .7 which is what most people aim for these days. Trick the box! get the most out of every enclosure. i'd trade a few $ for a permanent performance increase.


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