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Small sub: 2 6 1/2" drivers or 1 8"? Which one is better?

Discussion in 'Home Theater Projects' started by Javier_Huerta, Dec 12, 2005.

  1. Javier_Huerta

    Javier_Huerta Supporting Actor

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    Hi all!

    After finishing my IB sub, I'd like to build a small ported sub.

    I've been looking at the TB drivers:

    http://www.partsexpress.com/pe/pshow...number=264-854

    http://www.partsexpress.com/pe/pshow...number=264-832

    Due to s/h to Mexico, a pair of 6 1/2" are "only" $20 more expensive than the 8".

    I'm thinking about a 14" cube (or so), tuned at around 28 Hz with a 3" port (if memory serves me right) for the 8" driver. That gives me approximately 40L of volume.

    If I were to build a sub with the 6 1/2", I'd have to build a slightly deeper box for both drivers.

    I've been simulating both options extensively, and I find similar performance among both options, with a little less distortion from the 6 1/2" drivers.

    I'll be feeding them with the 300-794 plate amp.

    Would you build the 8" sub, or the pair of 6 1/2" one? why? Is there a disadvantage for either driver? They both seem great.
     
  2. Stephen Hopkins

    Stephen Hopkins HW Reviewer
    HW Reviewer

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    I was playing around w/ the idea of building a TB based bedroom HT and that 8" driver and it models pretty well in a ported enclosure similar to the one you've described. They do, however, lack excursion (like most any 8" driver will) and aren't going to be able to hit refference levels. I'd say the amp you've selected may be a bit too much power.

    Have you thought about a 10" driver? The Dayton High Output 10" (295-466) would work very well in the box you've described, with an F3 of 26hz and ruler flat frequency responce. A Dayton Titanic MKIII 10" in that box would have an F3 of 25hz w/ a slight bump (less than 1db) at around 32hz. Either could be ran with one of the lower powered 120w PE amps, but the Titanic could also handle the power of one of the 250w amps as well. If you went w/ the 120w amp and the Titanic MKIII 10" you'd be looking at a cost of only $40 more than the dual 6.5"s and a 250w amp and I believe you'd have MUCH better sub (going lower and louder) in the same box you've already decided on.
     
  3. Javier_Huerta

    Javier_Huerta Supporting Actor

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    Hi Stephen, thanks for your answer!

    I should have been more clear in my post... I already have the amp, and I'm looking for a driver. With S/H to Mexico, the prices are as follows...

    1) 8" TB sub: $110
    2) 2 6" TB subs: $140
    3) Titanic 10" sub: $240

    [​IMG] So, I guess I'll have to pass on the Titanic.

    Since I already have the amp, I just hope either one of the small subs can take the power. I'd assume the 2 6" subs would behave better, since they'd be receiving 180 watts of power (at 8 ohms). According to my calculations, the 8" would be hitting Xmax within the box I designed at 272W. I know the motor may not be able to take that much power, but since I'll be using it for music, I'm not very worried about it.
     
  4. Joey Skinner

    Joey Skinner Second Unit

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    I made a small ported sub for my computer with the TB 6.5" Neo and a 70w amp and it exceeded my expectations. Two of the 6.5"s will move more air than the 8" so for an extra 20-30 dollars I'd take the 6.5"s.
     
  5. Wayne Ernst

    Wayne Ernst Cinematographer

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    Javier,

    MCM also has an 8" high-excursion subwoofer. You might want to dig up a few datails on that sub, too. Last time I checked, it costs a bit less than the Tang Band 8" driver. Plus, the shipping might be less through MCM.
     
  6. Geoff L

    Geoff L Screenwriter

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    The long throw original released 8" MCM had problems. Not sure if they where/have been addressed or not. Cone sag from it's apparently poor/cheap designed suspension (even when used in a standard front face mount). Said to sound great for awhile and soon, very short time, it's no longer aligned properly in the gap and goes to crap.

    This is not to say it has not been addressed if still available. I do not know, but read about the problem extensivly. Sorry can't locate the link showing the testing of both the TB-8 and MCM-8 at this time.

    Given what you want, what you have amp wise, and what your looking for, I tend to agree the dual TB 6.5's in series might be the way to go. All those that have used the little TB W6 sub vented have been shocked at it's output. A pair would be rather impressive for a small sub and your power on tap would be in the ballpark.

    You might want to read this little diddy using the TB-6.5-->W6-1139 "SC" version. (Not sure if it's a typo or it's the first gen TB W6 driver). A few of his TSP's listed also are different than what PE shows, he may have measured the driver (no mention of it) or again it maybe a first gen W6...
    [​IMG]

    His rather cute 11" vented cube might give you an idea of what one it's capable of in the size cab he chose and the PE 70-watt plate amp he also used. Apparently built to match up well with some mini microbes he built. He had to make a trade off in port size which he explains, etc along with alot of other interesting stuff including graphs.

    http://www.rjbaudio.com/Cerberus/cerberus.html

    Cheers
    Geoff ¥
     
  7. Wayne Ernst

    Wayne Ernst Cinematographer

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    Geoff,

    Thanks for the information on the 8" MCM driver. The driver is still present on the MCM site and listed as being available. But, from your information, it seems like it could be a bit risky to go through the whole installation and then have it suffer in performance. I guess after the initial issues were reported with the driver, nobody felt it was worth the risk to see if the issues were resolved.

    Javier,

    I also wonder if you couldn't find a capable car audio sub that would model well for in-home use? The subs you listed were all models that were from the U.S., which quickly jumped in price when you added shipping and customs details for your country. Certainly, you might be able to find something decent locally that would yield the performance you're looking for?
     
  8. Javier_Huerta

    Javier_Huerta Supporting Actor

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    Hi Wayne,

    I can find many subs around here. Unfortunately, they are not very nice models. They certainly don't have as much Xmax or have as much quality as the PE drivers. [​IMG] I've learned that it's better to buy a more expensive model from the start - quality pays! [​IMG]

    I decided to get the dual 6.5" drivers. I think they model a bit better (especially because of the Levc). I have heard way too many good things about them.

    I'm now wondering whether I should build a downfiring subwoofer or a bipolar one. Any thoughts? Maybe a bipolar one would take care of baffle step diffraction and help a lot with placement... I'm not sure, I think I need to read a lot more on the subject.
     

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