update on mystery diy speakers,

Discussion in 'Home Theater Projects' started by Mike SJ, May 17, 2004.

  1. Mike SJ

    Mike SJ Supporting Actor

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  2. Patrick Sun

    Patrick Sun Moderator
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    One more item, starting so many thread leads to a lack of continuity in discussion because even though you know what midrange driver you are talking about, someone coming into this thread has absolutely no idea what midrange you are talking about, and the urge to offer help quickly subsides.
     
  3. Mike SJ

    Mike SJ Supporting Actor

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  4. Shawn Keeler

    Shawn Keeler Stunt Coordinator

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    Any pics of these bad boys?
     
  5. Mike SJ

    Mike SJ Supporting Actor

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  6. RichardHOS

    RichardHOS Second Unit

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    I've never seen yellow carbon, so it's probably kevlar unless painted or otherwise coated.
     
  7. Mike SJ

    Mike SJ Supporting Actor

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  8. Mike SJ

    Mike SJ Supporting Actor

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  9. Aaron Gilbert

    Aaron Gilbert Second Unit

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    Ported box? That would not be my conclusion, given the limited specifications above. That's not to say you couldn't use a ported box, it just wouldn't be my first choice. With a Qts and Vas as high as you have, the resulting box will be HUGE, although it will be flat well into the 40's and maybe below. Granted, you could use a bit smaller box, but at the expense of accuracy (flat response and good transient response).

    I've always been curious on the response of those drivers, given their low price and shielded nature. The pincushion frame bugs me, but wouldn't be an issue for a situation behind a grill. 1.5" voice coil is unusually large for a 6.5", I wouldn't be surprised if it handles more than the 40w they say.

    With that high Qts and relatively low Fs, plus the cone and surround construction, it would make a great candidate for a car woofer in a large door or on a rear deck.


    Aaron Gilbert
     
  10. Mike SJ

    Mike SJ Supporting Actor

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  11. Patrick Sun

    Patrick Sun Moderator
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    5KHz is pretty high to cross a 6.5" midwoofer. I'd think that 3KHz or below is a better range to consider.
     
  12. Mike SJ

    Mike SJ Supporting Actor

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  13. Aaron Gilbert

    Aaron Gilbert Second Unit

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    I agree with Patrick, for an ideal speaker, 5kHz is a bit high to cross a 6.5" woofer, due to the greatly dropping off axis response above about 3k or slightly below. That said, I am a firm believer in trying unconventional and often too-simple-to-work type ideas. One of my recent pair of speakers uses a Dayton 6.5" woofer (Parts Express 295-306) running full range, combined with a Morel MDT-12 1" tweeter with a single capacitor for about a 3kHz high pass. I wasn't expecting it to sound that great, but amazingly, it blew away all my other speakers that had far more thought put into them. Partly I'm sure this is due to the fact that the woofer has a steep but smooth natural rolloff right around 3kHz.

    Regarding the fiberglass cones in question, without a frequency response graph, we can't really say what may or may not work. Fiberglass cones sometimes, but not always, have break up resonances and peaks in the upper frequencies, which should be avoided. We do know that The off-axis from 3k-5kHz may suffer a bit, but whether that's dramatic will depend on both the room and typical listening position. If it's a huge room and you always sit in the sweet spot, the effect may be negligible.


    Aaron Gilbert
     
  14. Aaron Gilbert

    Aaron Gilbert Second Unit

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    Oh by the way Mike, that 7 liter box is insanely small! That will give you a Qtc of 1.1, which produces a response with a peak of 2dB at 106Hz. I imagine it sounds pretty strong in the bass, eh? Transient response won't be that great, but on the upside, power handling is the highest you can get in a sealed box. [​IMG]


    Aaron Gilbert
     
  15. Mike SJ

    Mike SJ Supporting Actor

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  16. Aaron Gilbert

    Aaron Gilbert Second Unit

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    Just for the record, these woofers have a fiberglass cone, not Kevlar. Kevlar can be yellow as well, but it can also be black (the Adire Shiva cone has Kevlar in it, for instance).

    In any case, what's important is that you are happy with the sound. All the theory and ideal design choices don't really mean much once you are satisfied. Enjoy!


    Aaron Gilbert
     
  17. Mike SJ

    Mike SJ Supporting Actor

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  18. John Wes

    John Wes Stunt Coordinator

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    5k for the crossover? For a 2 way? I'm not an expert but isn't that a bit high if the specs on the tweeter are any good?
     
  19. Mike SJ

    Mike SJ Supporting Actor

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  20. John Wes

    John Wes Stunt Coordinator

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    Humm........again I'm not an expert but it seems a decient tweeter. At least for the money. Seas make excellent high end tweeters...That one seems to be a mid level tweeter. I suppose it could have been crossed over lower but again, I'm not an expert. [​IMG]
     

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