continuing quest for the best sub design for me - push pull design?

Discussion in 'Home Theater Projects' started by Geno, Jun 12, 2003.

  1. Geno

    Geno Supporting Actor

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    I am still looking all over for the best way to enclose my 2 10" woofers. I know I know, if I had specs on them I could just feed them into a program or post them here.... well I dont have any specs and retesting them wont happen for a while. Although I will definately get the real specs before I commit to a design. My ? is, if I am trying put 2 drivers into one box, is the push pull idea something to consider or are there better 2 driver sub designs. I am going for a better musical sub over a better HT sub.
    Theseare high excursion drivers, I just dont know how high [​IMG]

    please help me
     
  2. if we are just looking at alignments as far as "which is better" and completely disregard driver specs.

    Push Pull=lowest distortion
    Isobaric= smallest box
    Horn loaded= easiest to drive
    Proted/PR=best extension
    Dipole=smoothest room intereaction

    why mention all these? well...lets suppose that your sub has 5mm xmax and a sealed F3 (Q=0.707) of 80hz. well..this would SUCK as a sub......but it migh model extremely nicely as a horn. ... etc.

    Dipoles are usually regarded as having the best sound, but they chew up GOBS of excursion if you are driving them low..plus, they REQUIRE active circuitry.

    To really make a good call, I think we need specs. ...sorry/
     
  3. TimForman

    TimForman Supporting Actor

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    Someone else had a post similar to this. They remarked that there are some retail subs that use two smaller front firing drivers in tandem to generate volume displacement equivalent to one large driver. I don't know if this is a car audio or home audio application. Might be something to investigate.
     
  4. Greg Monfort

    Greg Monfort Supporting Actor

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    Hmm, compression horns ultimately have the lowest distortion, and high displacement IBs and TLs can come 'close enough'. A push-pull bipolar TL is IMO theoretically the best tradeoff between distortion and semi-manageable cab size if the system Fb is >20Hz. Below 20Hz, bipolar PRs rule IMO. In reality though I've found that a bipolar layout with the mags touching works better than push-pull, but it can make for an extremely WAF unacceptable cab and placement issues can be tough to overcome also if it has a very high aspect ratio.

    Since the 10" aren't likely to be suitable for infrasonic duty, and with no specs available, a mag touching bipolar TL appears to be the no-brainer to me. Indeed, due to the latitude stuffing allows WRT tuning, using averaged 10" specs for whatever they were originally designed for (sub/PA/whatever), a decent (though I seriously doubt optimum) performing cab can be realized.

    GM
     
  5. TimForman

    TimForman Supporting Actor

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    This post got me thinking. I built a Shiva tube about 175 liter vented and was disappointed with the muddy sound and amount of vibration generated by the tube itself. When Greg reminded me of the TL subs I remembered this link .
    I removed the end cap with the vent, set the formerly horizontal sub upright and stuffed about 6 lbs of poly-fil into the tube. VIOLA! The sound is so much better now. This is what I was shooting for! I really like the TL design idea for it's simplicity, small footprint and great sound.
     
  6. Geno

    Geno Supporting Actor

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    Greg, Just so I understand correctly, a mag touching TL would resemble a scaled down version of this, just with the woofers opposite each other and having the same polarity??

    http://www.passdiy.com/speakers.htm
     
  7. Greg Monfort

    Greg Monfort Supporting Actor

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    Hey Tim, I'd completely forgotten that Dave had that Shiva tube project or I would've linked it. Thanks for reminding me and glad my response had a positive result. [​IMG]

    Geno, kinda-sorta. It would be rectangular in design all the way since smoother response comes from positioning the drivers somewhere away from the end of the pipe based on several factors. You could use a tube on either side of a driver box of course, but it seems like wasted extra effort to me.

    GM
     

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