i think im biased

Discussion in 'Home Theater Projects' started by JoeGibs, Aug 31, 2005.

  1. JoeGibs

    JoeGibs Stunt Coordinator

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    [​IMG]

    this'll be the first home theater setup i do, and i'm doing it all DIY. the only thing in that pile that isnt going into it is the 10" titanic, that'll be going in my car. i'll be sure to post pictures once i built the enclosures and get it all up and running.
     
  2. rob-h

    rob-h Second Unit

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    I think you have a lot of work before you can enjoy being biased[​IMG] Have fun and get to work!!
     
  3. SteveCallas

    SteveCallas Second Unit

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    I've entertained the notion of building my own mains, but I don't know crap about crossovers. I realize they are just as important as the drivers you choose, and they are something you don't want to screw up. Are the crossovers from parts express any good, or are they more suited to the low end? If you had a premade crossover like those, would you have to build your speakers around them?
     
  4. Joe L.

    Joe L. Stunt Coordinator

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    Steve,

    To do the job right, the crossover must be designed with the specific drivers, their individual frequency responses, impedances, resonances, relative efficiencies, and the specific enclosure dimensions in mind. It is hard to tell from JoeGib's picture if his crossovers are off-the-shelf, but if they are, odds are they might not do the drivers justice. In fact, the odds of an off-the-shelf crossover being perfect for any DIY effort is almost non-existent.

    Yes, the off-the-shelf crossover will work to some degree, but the results will not be anywhere near optimal. I mean, even the cheapest speakers with a single capacitor in line with the tweeter as their "crossover" will make sounds and play music, but none will be suitable for the true audiophile.

    Instead, if you are not up to designing the crossover yourself, follow the plans of a DIY'er who was up to the task and who has put in the effort of designing the crossover. There are quite a few kits and plans on the web. They will specify the drivers, the crossover components and schematic, and the enclosure dimensions. Do a bit of research and you will see which ones are worth duplicating. In many cases, the crossover components will cost as much as the drivers. They really are that important in the way the speakers will sound.

    Joe L.
     
  5. SteveCallas

    SteveCallas Second Unit

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    As much trouble, labor, and headaches as a premade, proven plan for DIY speakers would save me, I would only go DIY for mains if I pursued this project I have had in my head. It would be very smiliar to this:

    [​IMG]

    The "innovative" design feature I wanted to employ would be to have each driver isolated in its own sonotube, with the volume maximized for its specific response. The tubes would fit into the main cabinet by fitting snugly into braces with holes a little larger than the diameter of the tubes that would be lined with weatherstrip. This way, I would get the best performance possible out of each driver, and I would have basically no internal resonances. The speakers would have to be pretty deep, but they would be as thin as the widest driver.

    I would position the tweeter slightly off center to the inside and have one woofer on top and one on bottom, so if I made a center channel, it would be identical to the mains except on its side, and I would avoid that tweeter reponse problem that occurs in the D'apollo design, or whatever it is called. I believe Wilson or some other high end speaker maker uses exactly the design I am picturing.

    Without knowing too much about building speakers, I was thinking of going with the vifa ring tweeter, 2 4" or 5" mid ranges, and 2 10" woofers.

    The problem is I don't know crap about building loudspeakers. I don't know about impedance matching or crossover circuits. I just build a sonosub that totally exceeded my expectations, but I know loudspeakers are WAY more complicated.

    I will be buying some new speakers soon - either Ascends, Paradigm Studios, or Boston Acoustics, but I am just now starting to look into this and do some learning. Maybe after a year or so I will have picked up enough info to take it more seriously. But the crossover aspect just baffles me - I understand what it does, but I don't know how it goes about doing it.
     

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