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Discussion Starter · #1 ·
So I've got a question for the gallery.

First my goals for these subs are NOT HT. I do however listen to some bass heavy stuff like dubstep and the like so I like bass, but I dont needo 120db bass down to 1hz :).

I was given 2 Infinity Kappa 120.3 Perfect subs. Now I know that I've seen a LOT of Infinity 1262 dual opposed builds lately.

The Kappas only need 350 wpc and are a DVC 4 ohm load. That means by itself I can either get a 8 or 2 ohm load. If I wire them together I can get a 4 or 1 ohm load.

Here is what I am wondering about. I REALLY like the concept of going with multiple subs placed around the room for a smooth response over the entire room. I also like sealed since the boxes are smaller and easier to put together. I'm wanting to try and pull off 4 total. Since I only have 2 Kappa 12" I was thinking about either buying 2 more (of the current Kappa 12" subs), so I match brand and T/S specs OR going with 2 1262's since I'm gonna guess they are a bit cheaper.

Now here is my question. If I build 4 sealed boxes how big a difference is it going to make for EQ purposes if I wire them into 2 pairs so I get a 4 ohm load total? Its MUCH easier to find a 600 wpc x 2 @ 4 ohm amp v a 350 wpc x 2 @ 8 ohms x 2 amps.

Will that work decent?
 

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Just for clarification, if you plan on wiring them into pairs then you will be setting the EQ as if you had two subs and not four. The subs in each of the pairs will need to be relatively close to each other as to act as a single sub in order for the EQ to be properly implemented. For example you can have one pair of subs in the front of the room and one pair in the back, but you cannot have one sub in each of the four walls in a rectangular room. If you want four subs to have smoother response then you will need four channels of amplification along with an EQ capable of handling four channels.

That being said, setting up proper EQ for two channels is relatively simple once you learn how to use REW. It can be done without it, but it will be tedious and take considerably longer all while being less accurate. I haven't tried EQing more than two channels yet so I don't yet know how much more difficult it would be, but with a good understanding of REW it shouldn't be that much more difficult.
 

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Do you think you need subs in four locations instead of just building a pair of DO subs and putting them in two locations? Any way to test and measure with subs you already have?

You could get two NU1000DSPs for $400 and have 4 channels of EQ. With only two channels, an NU3000DSP might only push 550-600W into the Kappas at 4 ohms on one channel. That might be good enough, and you could get a pair of 1260ws for the other two subs, and run that pair in parallel for a 2 ohm load and no shortage of power. If you want to guarantee you'll have all the power you need, the NU6000DSP would do that, or the NU46000 with an outboard DSP for four channels of amplification and EQ...
 

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Discussion Starter · #4 ·
Do you think you need subs in four locations instead of just building a pair of DO subs and putting them in two locations? Any way to test and measure with subs you already have?
Dont know if I need it. Probably dont and it would be overkill, but 4 small 1 cubic foot sealed boxes are easy to place. Even 2 are not that bad. No way to measure the Kappa's right now as they are in cardboard box and I haven't sourced any material for a box for the subs. The Elemental Designs A2-300 is what I am using now and will be dialing things in shortly with a new pre-amp thats coming.

I think 4 could be overkill and the cost associated with it will likely be more than I'm willing to do if I have to run each sub on its own channel (which is preferred anyway).

Was just thinking out loud.
 

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I have a pair of 1260ws in 1.4CF sealed boxes powered by an NU3000DSP in my bedroom, which is 11x14 or so, and that's all I need in that space. Music barely gets it ticking, even with a pretty full house curve on the subs. Movies can get it thumping pretty hard if I crank up the volume, but it's not a room where I'd try to come anywhere close to "reference" volume, even -10 is too loud in there. Most usage is at -30 to -25 on the AVR. The response rolls off pretty fast below 20 Hz, surprised that room gain doesn't keep that alive a little longer, but it doesn't bother me at all in the bedroom. The boxes do rock a little when played hard, that could be part of it, as they're only 12" deep on axis behind the driver, 18 by 18 tall/wide, and not too heavy, from 3/4" ply.

So you might just take a shot with what you've got. Or if you think the space is large enough to need a little more, just go straight for a pair of DO boxes to keep the amplification simple.
 
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