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Discussion Starter · #1 ·
Hoping those of you who have booted winISD more than once would give me a quick nod yes on this.

I'm a 2 channel listener, all kinds of content; but most critical with music. Since I currently run Zaph 5.3MTM's which are a bit light on bass, I wanted to build a pair of subs. Based on a combination of budget, space, and the desire to cross relatively high (200Hz?) with the LR's; it seemed like 2x RSS390HF's in DIYSG Kuda 15 ported boxes would be a good choice.

I believe I've modeled this correctly in WinISD; about -3db at a 23Hz tune and -6 db at 20Hz:
3157222[/ATTACH]File"]Kuda M15.wpr
3157222

So a couple of questions:
  1. Any recommendations on crossover point given the 5.3MTM response
  2. Currently my HK3490 has sub out, but no in receiver crossover settings (IE send frequencies below X to sub out). If I planned to purchase an XLS1502 for these; any recommendations on how I might set this up? I guess I wouldn't be able to set a high pass on my LR's unless I bought some sort of digital crossover before my amp?
  3. I recognize both the cabinet and driver are unavailable presently. I was originally just pleased with the <$400 ea for the driver and box. I can wait; but perhaps others would make suggestions. I'd prefer a 'musical' sub over max SPL for what that's worth.
Thank you, I've enjoyed reading this forum for years. Its time for me to build again.
 

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The dsp in the XLS 1502 is pretty worthless, the hpf only goes down to 30hz, so You'll need a dsp like a miniDSP-HD , or Dayton Audio DSP-408 to set your hpf and lpf , room corrections, for the subwoofers. Considered a Behringer NX3000D, it cost about $390 and has a pretty good dsp in it. Does your HK3490 have a hpf for your main speakers to at least filter out the bass below 80hz ?
 

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Discussion Starter · #3 ·
Alright I'll take a second look at amps. The hk3490 does not have any crossover capability. So I will need to set a crossover up before the amp and feed analog to each amp.
 

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I would suggest buying a DSP / Crossover versus changing amps. Amps come and go, the DSP could last you a very long time, and give you a broad choice of amplifiers to use versus always being locked into amps with DSP. If you choose the Mini-DSP 2x4HD there are other cool things that they support beyond the basics.
One example
 

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Discussion Starter · #5 ·
Is there a go to amp if the minidsp will be handling all the dsp work? I guess the Beringer non dsp amps to save a couple bucks.
 

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what do you mean by, "go to amp"?
 

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Discussion Starter · #7 ·
When I browse AVS, I usually see either Behringer or Crown sub amps. I think if I am using Minidsp for crossover work, I will probably pick a crown amp so I can skip doing a fan mod.
 

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If you really want to do it correctly, I'd suggest a fully programmable crossover, MiniDSP I expect would be fine, and then a separate power amplifier for both the main speakers and the subwoofers, so that you an apply filtering to both the mains and the subwoofers. If you don't do both, you don't have a crossover, you have a subwoofer running up on top of the main speakers, and some people might be okay with that, depending on how they luck out, but it can also yield terrible results, 'fixing' some things and creating other problems.

The response of your mains that you posted looks like a ported design, in which case I would suggest, at least as a starting point, a crossover in the 120 Hz range (get it away from the port output to simplify so that you're not dealing with the port's phase characteristics, or the likely driver resonance either, with a 4th order Linkwitz Riley filter on both sides, and adjust time alignment in your DSP if you've got it, so that at your main listening position, equidistant to both left/right speakers, and using a tone generator at the crossover point, such that the subwoofer level by itself is equal, and the main speakers by themselves are equal, (Turn on only one amp at a time when measuring this), when you invert the polarity of the subwoofer, you get the greatest null, or the most cancellation, or the least output. The starting point of the delay should be roughly the difference in feet, such that the delay is applied to the closer channels, in the amount that is the difference of distance. If you have an amplifier with DSP, there will be additional delay imparted most likely.

When you restore correct polarity, the combined response should be about 6 dB higher than the low pass or the high pass sides of the filter individually.

It is an imperfect quick and dirty starting point. Play with crossover points, delay, crossover shapes, etc., ad nauseum until it sounds great.

Oh, BTW, you're going to want REW and a UMIK or something equivalent to place your sub(s), just in case nobody else already mentioned it, but I'd guess they already have.
 

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There's the Crown XLI-1500. It's rated at 450 watts rms per channel at 4 ohms. Just so you know it's not rated for 2 ohms per channel, only 4 ohms. Also, it's not rated for 4 ohms bridged, only 8 ohms at 900 watts rms. It's a class A/B, not class D, so it's going to draw more power than a class D power amp. If you need/want the flexibility to 2 ohms in 2 channel, and 4 ohms bridged, then the Crown XLS-1502 is a good option.
Btw, I run two bridged 1502's myself, and I've never had any issues with either one.
 
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