Altec 811B Horn + Big Woofer DIY System

Discussion in 'DIY' started by spwath, Jan 8, 2018.

  1. Cspirou

    Cspirou They call me Sparky

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    Not super expensive, but not the cheapest either. MiniDSP doesn't cost too much as well as the Behringer DCX2496.

    But you will need two stereo amps.
     
  2. dmckean44

    dmckean44 In a Sherwood S6040CP relationship

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    It looks like the used Behringers are under $200. Trying to build a passive through trial error could get expensive too, I would think.
     
  3. spwath

    spwath Hijinks master cum laudle

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    So I could get the mini dsp 2x4 and it would work for that? As long as I have 2 amps that is.
     
  4. Cspirou

    Cspirou They call me Sparky

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    Yep. I think you can get it without a case for under $100
     
  5. spwath

    spwath Hijinks master cum laudle

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    Only thing I'm hesitant about is puting some cheap d/a and a/d converters in the signal path like the mini dsp would do. Are all advice crossovers digital?
     
  6. Thad E Ginathom

    Thad E Ginathom Friend

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    Are all variable/tunable crossovers active?

    I wish I knew... I visited a guy about five years ago with super ex-cinema-driver set up in a fairly big dedicated listening room (with the DIY workshop around the back :) ). At first, I wasn't that impressed with what I was hearing. He jumped up and moved some sliders on a box: tuned the whole system to my ears and taste in a jiffy!

    Trouble is, I never did get my head around his setup, and I certainly don't have a name for that box. It certainly didn't look digital, nor did it look expensive. It had that Radioshack look. All I am fairly sure of is that it was a crossover (or two... or was it both channels in one box)

    What could it have been!

    Anyway, I was just astonished at the flexibility. And the skill, actually. He was in music production business, and, no doubt, knew his frequencies. Maybe I could have done it by trial and error, eventually.
     
  7. Cspirou

    Cspirou They call me Sparky

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    The digital ones give you far more options in terms of configuration and experimentation. ASP is good when you know your crossover points but unless you get the really expensive ones, you aren't going to get too configurable.

    There's a bunch of options though with the MiniDSP universe. You can get an add-on board which allows digital input. You can also get the MiniDSP HD which has digital input and a SHARC proceessor. Or for full digital in/digital out you can get the nanoDIGI with 4 x SPDIF outputs and you can use your own DACs. You will need at least two DACs.

    Edit:

    Over at diyaudio, Nelson Pass is going to come out with an active crossover that won't need super rare JFETs.
     
  8. spwath

    spwath Hijinks master cum laudle

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    Hmm, ok. I'll probably just go with the 2x4 because it's cheap, and I probably won't even notice a difference with the better ones.
     
  9. spwath

    spwath Hijinks master cum laudle

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    Actually I have an old Yamaha dsp thing that might be an active crossover. I'll have to check...
     
  10. spwath

    spwath Hijinks master cum laudle

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    Got the JBLs. Guy threw in cables and a JBL E140 for free, and a Crown Power Base 2 amp for $50 extra. $300 total for both speakers and the amp.

    Pretty big...
    [​IMG]
     
  11. Cspirou

    Cspirou They call me Sparky

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    Rugged with grills too. You can take those outdoors for parties
     
  12. spwath

    spwath Hijinks master cum laudle

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    So i showed up at this guys house, in his garage was a Tesla Model S, and a Porsche 911. Also had a pickup truck. Pretty nice place....
     
  13. spwath

    spwath Hijinks master cum laudle

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    Yeah. Nice rugged build, grills will prevent stupid people from sticking fingers through woofer. I'm hoping my 811 horns will fit where the existing horns are, or at least with a little modification.
     
  14. spwath

    spwath Hijinks master cum laudle

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    So, now for amplification. Bi amping is what ill do. I'm thinking for my use at home, Jonokuchi for the tweeters, and I might buy one of those aliexpress JL hoods for the lows. Now for college, might be better to have something easier for my roomates and such to use/leave on 24/7, so I might use the aliexpress JL hood for the highs, and the Crown Power Base 2 I got with them for the lows.

    That sound good? Any issues with that? Or should I sell the crown power base 2 and get something different, maybe another JL hood?
     
  15. Cspirou

    Cspirou They call me Sparky

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    Are you going to use the pioneer DSP for volume control? Because you are going to need a preamp for sure
     
  16. spwath

    spwath Hijinks master cum laudle

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    Yes. That or my Onkyo receiver has that function too
     
  17. spwath

    spwath Hijinks master cum laudle

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    Though I would prefer to use the pioneer, simpler and smaller, plus... Motorized volume knob.
     
  18. philipmorgan

    philipmorgan Member of the month

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    I'd look at solid state for the lows (your Crown Power Base 2 seems good for now) and tube for the highs, so basically stick with what you've got. I have a JLH69 and amps like that aren't known for grip or slam in the lows. I think of them as better used for mid/high duty, but your existing tube amp might be just as good or better there.
     
  19. spwath

    spwath Hijinks master cum laudle

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    Sounds like a plan, and doesn't require me to buy anything else! That's the best plan.
     
  20. Jim Hodgson

    Jim Hodgson New

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    Having been down this road (starting with Altec 811 horns like spwath), I found it very helpful to draw on the collective experience of today’s Altec DIY crowd — which is larger than one might imagine. In particular, there seems to be a pretty specific recipe for assembling Altec parts harvested from the company’s vintage commercial speakers:
    • 12” Altec 414 woofer
    • Modern repro Altec 614 BR cabinets (which are ~3 cu. ft.)
    • 1” Altec compression driver like 802, 804, or 806
    • Altec 32 horn
    A search should turn up many examples of — and also some close variations on — this recipe. I can attest to the fact that it makes for a very manageable hybrid horn system that’s nicely suited to a typical domestic environment.

    In my case, I settled on this proven bass configuration and enjoyed the fact that it’s amenable to a wide range of crossover points and even to running full-range (which is a peculiarity of this particular 12” driver). After experimenting with some different high frequency horns and drivers, I mated my Altec 804 CDs to 650Hz round Tractrix Edgarhorns, which I preferred to any of the Altec horns. I also liked 2” JBL 2441s on 2397 Smith horns ... and that’s something that I could see revisiting.

    Whatever the specific equipment woes, there are a few principles that I took away from my meanderings as being broadly applicable:

    1. Deciding on the usable frequency range of a horn is much more complicated than learning its published specs — relying, for example, on the claim that the Altec 811 is usable down to 800Hz. This may be accurate for some purpose or another (probably sound reinforcement in the case of the 811), but any real conclusion is bound to be both (i) specific to such additional parameters as driver construction and chosen crossover; and (ii) personal with respect to one’s goals for distortion, frequency response, phase, dispersion, imaging, etc.

    2. A simple crossover, and even a good implementation of basic “tweeter protection” in the form of an excellent cap, is often enough, here — and can be wonderful.

    3. When mixing directly radiated bass and horn loaded treble, it pays to avoid crossing, especially abruptly, in the vocal range — with fundamentals in the roughly 80Hz - 1050Hz range and important low order harmonics up to 2000Hz or 3000Hz. That’s a tall order, though, and I guess we just do our best.

    4. Bi-amping such hybrids can be a slick way to go — with, for example, a Class A solid state amp (think First Watt) on bottom and a flea powered SET amp (think DHTs like 45 and 2a3) on top.

    Anyway! As I continue with my own experiments, I wish you a lot of luck with your project...
     

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