XO Questions (and stuff)

Discussion in 'DIY Speakers and Subwoofers' started by mfaughn, Mar 4, 2013.

  1. After patiently waiting for the DNA-360 drivers to be in stock I finally have a pair, as well as SEOS 12 waveguides. Now to work out the woofer side of things. I tried them out by setting them atop a pair of bass bins from a set of Frazier Dixielanders, bi-amping with an active XO. These bass bins are interesting but have some fairly significant shortcomings to my ear. At any rate, this gave me a clue as to what I can expect and I am really looking forward to what they'll sound like with a better bottom. So, about that bottom.

    Boxes: I have on hand a couple of pairs of boxes that bear consideration. One set is from some Pioneer CS-63. They are pretty big, I think around 3.2cf, and built of really nice, thick plywood (that looks to be fairly void-free). They are really solid boxes but need new veneer. They are cut for 15" woofers now. I also have a pair of solid maple cabs that I picked up. Well, not totally solid since I'll need to make a new baffle board and rear panel for them. Anyway, they're pretty nice, although they are kinda short and deep. They are closer to 4cf. I could always build new boxes if there is a really good reason to do so. I'm fine with big boxes. My current mains are Snell A/iii...i.e. refrigerators with veneer and grill cloth.

    Drivers: I have a pair of DC300-8's that I got on freecycle. I've considered various options, either 12" or 15" and it seems like the Eminence 2512-II is a good bet. I'd like to have something fairly high efficiency so that if I ever do use them with a single amp I can still use something fairly low powered. It would be nice to get by without subs for a little while but eventually I'll build some. I don't really give a hoot about movie bass. I'm interested in music bass...though I am a bit of a basshead. Actually, I do have a sub now that can fill in until I can build what I want (leaning towards a pair of these). Anyanyanyanyaaannnnywayyy...Just wondering what other folks might think of dropping into cabs in the size range I mentioned above (and why)?

    The real questions:
    • For the published XO designs, lets take the one that works with the 2512 for instance. Does cab size of tuning matter a lot? My meager understanding is that the XO is controlling the slope and point of crossover and perhaps the phase, while the cabinet size and tuning is concerned with the other end of the woofer's FR curve for the most part. Am I mostly right, mostly wrong, or what? I'd love a good, readable reference on this that was accessible to a non-expert.
    • Is there any reason not to go with a mini-DSP for crossover given that I'm perfectly happy with bi-amping?
    Auxillary question:
    • Once a good solution is found with a miniDSP, can that be reasonably translated into a passive crossover that would facilitate using a single amp?
    OK, thanks for reading this far folks. Thanks even more for any thoughts you might share.
  2. mfaugn,

    The box type or tuning doesn't affect the crossover (unless you are doing BSC in the crossover, then baffle size and distances from walls and floors get into it).

    No reasodn not to use Minidsp as long as you have preamp outputs on your receiver or an audio preamp /control unit. And spare power amplifiers.

    But the Minidsp design you come up with won't likely be much help for doing a passive crossover. Active crossover doesn't care about driver impedance curves or sensitivities. And with dsp types fine eq and delay adjustment become trivial; both are very difficult with passive crossover.
  3. Thanks very much Mr. Waslo :) . Will proceed with miniDSP. Sounds like it will make it easier to fool around with different drivers.

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