Altec 811B Horn + Big Woofer DIY System

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

  1. Hrodulf

    Hrodulf Friend

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    Why would an inherently unlinear (inductive) passive element sound better than a resistor based voltage divider?
     
  2. dmckean44

    dmckean44 In a Sherwood S6040CP relationship

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    I'm not really sure of the reasons (maybe someone else here knows better), but in my experience building speaker crossovers, autotransformers have a much more dynamic and clear sound than resistive attenuators.
     
  3. Priidik

    Priidik Friend

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    An audio transformer is not significantly nonlinear in audio range.
    Matter of perspective I suppose. For lots of folks devices with signal transformers are 'effect blocks'.

    When the subject is dialing down woofer, then the transformer would act like decent voltage source, while L-pad won't (poor damping and resulting screw up in driver Qts). For mid or tweeter I suppose maintaining correct Qts still matters, only the acoustic impact is less severe.
    For @spwath I recommend matching drivers for sensitivity as good as possible, with woofer having the least sensitivity in compromise. I bet the xo transformers are not cheap and no matter how good, they degrade the signal.
     
  4. purr1n

    purr1n Finding his inner redneck

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    Still need to ship you horns. Have not forgotten.
     
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  5. Thad E Ginathom

    Thad E Ginathom Friend

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    OH... MY... GOD...

    Please... one for the speaker-porn thread. They don't gut much more porno (whilst still repembling normal speakers) than that

    :punk:
     
  6. spwath

    spwath Pubeless Playboy

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    Ok, i found some woofers. I am getting a pair of JBL 2226h's (inside a pair of JBL PA speakers) for $250.
    Now I need to start thinking about the crossovers.
    Also, I should figure out how much power these can handle, and design an appropriate crossover.
    How do I know how much power the speakers can take if the tweeter is 100w max, and woofer is 600w max?
    And I dont know where to start with crossovers, there are so many different types, not sure what is better. Probably going to cross over around 600hz, at least somewhere between 500-800 hz.
     
  7. philipmorgan

    philipmorgan Member of the month

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    These are going in a dorm room or similar size room, right?
     
  8. spwath

    spwath Pubeless Playboy

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    Yeah, we have a living room thing in our on campus apartment. Im not saying we will ever be using close to max power capacity, but in the future, if things are different, or if I suddenly need to blast music outside or whatever, just would be nice to know.
     
  9. spwath

    spwath Pubeless Playboy

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    I also wonder about the possibility of making corner cabinets? That was a popular thing in the 1960s it seemed. Seems like that would nicely fit in the room. Pros/cons of corner speakers?
     
  10. Cspirou

    Cspirou They call me Sparky

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    If tweeter can take 100w and woofer 600w then it adds up to a max of 700w for the drivers. However adding a crossover can affect this quite a bit. The crossover might dissapate a lot of energy and you might need more power. Or depending on the driver sensitivity you might be limited by the horn and can only do 200w. Won't know until the final crossover is assembled.
     
  11. spwath

    spwath Pubeless Playboy

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    They both have aproximatly the same sensitivity. Woofer is 97db, tweeter, kinda hard to tell with the horn and such, but around there.
    I dont know where to start with crossover design though.
     
  12. philipmorgan

    philipmorgan Member of the month

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    I can only think of cons: 1) actually building the damn things 2) reduced versatility in terms of placement
     
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  13. Thad E Ginathom

    Thad E Ginathom Friend

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    You can put it anywhere that the rectangle in which it would fit would go. But I guess that is wasting space that could have been filled with more speaker cabinet. Is more always better? Or is maths and proportion more important than size?
     
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  14. spwath

    spwath Pubeless Playboy

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    I'll probably just use the existing jbl pa cabinets, remove the horn, and glue/screw a piece of wood over the horn hole. Then I'll just mount the altec horns on top.
    These things are going to be like 100+ pounds each though. 2226h woofers alone are 20+ pounds, add in the wood cabinet, the metal horn, and the large and heavy compression driver.
     
  15. Cspirou

    Cspirou They call me Sparky

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    I've you're going to mount the Altec horn on top then just leave the original JBL horn in there and disconnect it internally. Cabinets are designed for a certain volume and the horn likely displaces quite a bit. That's not to say it won't work with the horn removed, just that you should try both.
     
  16. spwath

    spwath Pubeless Playboy

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    I'll do some calculations and maybe change the ports a bit
     
  17. spwath

    spwath Pubeless Playboy

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    Looks like I'll be using the 811s, as Marv actually had 811s not 511s. So crossing over at 800hz, will be easier on the compression drivers anyway.
     
  18. philipmorgan

    philipmorgan Member of the month

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    This is not something I've verified personally, but several folks over at diyaudio claim that the frequency range specs for pro audio horn drivers are specced at max power. That means that if you're using them in a domestic setting at (considerably) lower power levels, you can go lower than the specced frequency range. FWIW.
     
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  19. dmckean44

    dmckean44 In a Sherwood S6040CP relationship

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    I wish Spwath had an active crossover of some type to play with so he could experiment.
     
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  20. spwath

    spwath Pubeless Playboy

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    Me too. But that sounds expensive.
     

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