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Please poke some holes in this concept before I waste time

Discussion in 'Amps and Cabs [BG]' started by basscooker, Jan 13, 2017.

  1. basscooker

    basscooker Commercial User

    Apr 11, 2010
    cincy ky
    Owner, ChopShopAmps
    Looking for knowledgeable designers input on a thought I had the other day.

    I imagined an 8x8 (or 8x10) three way cab. A pair of good robust subs in a ported enclosure, a bandpass 410, and a pair of mids. Three chambers, two port tuned.

    I'm figuring the sub chamber and 410 chamber tuned an octave apart, maybe 30 and 60 respectively. Using something like 70/3k as the filter points. (these numbers are just thrown out there). The 410 basically running full range, but high passed at about 70, low passed at around 3k, with a sub and mid drivers taking care of some content on either side of those two points.

    Okay, learning hat on. Poke some holes in my concept before I dive into searching drivers and modeling.

    A couple things I already know: Big and heavy. Could easily be a mud-maker in high volume situations, and the "sub" is overkill and unnecessary when FOH is present. It could be a power-suck, with low sensitivity subs eating up the majority of the amp's power.

    Responses to those: Wheels. Made for use when no FOH is present, two L-pads. Possibly a way to bypass the sub chamber, or give it an independent input. Details, details. First I need to hear if it's a case of physics not caring that my logic says it might work, lol.
  2. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    So much potential for (serious) phase response issues, in addition to the unsuitable nature of a bandpass enclosure for bass is just the beginning of the non-starter.
    MrCash, INTP, DChalo and 3 others like this.
  3. basscooker

    basscooker Commercial User

    Apr 11, 2010
    cincy ky
    Owner, ChopShopAmps
    And there.

    Thank you. If I can't come up with the reasons NOT to do something it drives me crazy. When (in this particular case) two days digging through threads, website after website and the cookbook I couldn't find the exact answer, I knew you'd come to the rescue. My sanity thanks you.

    / thread. ;)
    agedhorse likes this.
  4. A bit like asking chef to do it all with the carving knife. He ends up cutting his thumb off.
  5. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    What you are proposing reminds me of a Magnatone cabinet that Neil Young uses. They were built for trade shows, and music stores, not for retail sale.

    spankdaplank, deathness and Sartori like this.
  6. bolophonic


    Dec 10, 2009
    Durham, NC
    Don't forget to throw in some motorized louvers and a turbo-antenna on that thing.
  7. basscooker

    basscooker Commercial User

    Apr 11, 2010
    cincy ky
    Owner, ChopShopAmps
    Right. Well maybe I described it wrong. Two 8"subs. Four full range 8". Two 8" mids. Tune accordingly, find good filter points. So beyond those processes of tuning it and finding good frequencies to cross them over, phasing is something that can't be accounted for? I trust you're right, don't do it, but please elaborate. I'm having trouble with understanding how it would be different than three different cabs designed to work together as a 3 way system, but in a single box, tuned for an electric bass. It would require a two channel amp, I guess. Remember though, this thing never even made it to paper yet. Just a bunch of googlying and reading. On a phone. I need glasses now.
  8. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    The phase response of the "bandpass full range" (bandpass type boxes are anything but full range) will almost certainly very different than the other boxes, making a poor choice to combine with other boxes.

    This is a more complicated subject than you realize.
    tryinalearnDan likes this.
  9. Rick James

    Rick James Banned

    Feb 24, 2007
    New Jersey
    That arrangement ignores at least three basic rules of speaker design. First, the lower the frequency the more driver displacement you need. If you must use eight 8" then four of them should be subs, two midbasses, two midrange. Even better, six subs and two midrange, since 8" subs go high enough that they don't need midbasses. Second, the higher the frequency the smaller the cone size needs to be for dispersion. So instead of 8" midranges 6.5" would work better, and they must be vertically arrayed, or the dispersion will be halved. Third, you never have different drivers working in the same frequencies. Bag the full range drivers entirely, they've got no reason to be there. Last, why 8" subs? Instead of four 8" subs one 15" would would at least as well, probably better, and cost a lot less.
    Jules Meuffels likes this.
  10. basscooker

    basscooker Commercial User

    Apr 11, 2010
    cincy ky
    Owner, ChopShopAmps
    Purely an exercise in the journey to more complex bass cab designs. I greatly respect, all the knowledge and experience you guys bring to the table. My own doubts came into play immediately, but i couldn't find the right "no" in the mountains of pages i tore through. Thank you all again. Baby steps.
  11. Al Kraft

    Al Kraft Supporting Member

    May 2, 2016
    Northern Virginia
    Without being argumentative or asking you to give away trade secrets Andy, from a purely conceptual point of view how would this be tremendously different from two cabs on a stage, one being a sub-woofer and the other a high passed full range complementary cab? If it has to do with the drivers all being in the same cab and/or in close proximity and how the sound waves would propagate/interfere (phasing, combing, cabinet resonance, whatever,...) that would make sense to me.

    Thee are some rather full spectrum cabs out there that can already do almost sub lows to fairly high (relative to our ability to hear) frequencies, and they're in a single box. I can see it being a challenging problem - so are you saying that it is a lot more complex than would be worth the end result, or it's not likely that it could ever be pulled off with great results. Just curious to understand the science here a little better. Thanks! :)
    basscooker likes this.
  12. Grumry


    Jul 6, 2016
    I can picture it in my head but I pan out and it turns into the Dead's Wall.
    Sartori and DChalo like this.
  13. Peavey had a PA speaker system (3020HT) with the same sort of idea. Two massive cabs and a head. It sounded great, but it was an absolute nightmare to move around... I know. We rented the system for a gig—and the club was in the basement. Never again.

    But if you own a club and will never have to move it (or have roadies that you don't care about) go for it!

  14. seamonkey


    Aug 6, 2004
    "It's alive!"
    REV, L Anthony and agedhorse like this.
  15. BassUrges


    Mar 14, 2016
    I am in favor on the condition that you tri-amp it.
  16. pbassnut

    pbassnut Supporting Member

    Sep 27, 2004
    Falls Church, VA
    If you have money and time to burn and don't mind ending up with a white elephant that you either don't like or isn't quite what you expected (and would be difficult to sell in that case) ... sure, go for it. However, there are so many great options out there that you can actually try out to see if they work for you before taking the plunge. Keep it simple, get an Ampeg SVT and matching 8x10 and be done with it. ;^)
  17. Jules Meuffels

    Jules Meuffels Commercial User

    Apr 14, 2016
    The Netherlands
    Custom Shop Bass Cabinets
    2x8" or 2x10" wont give you the lows you're looking for (check the specs).
    The thing will be huge and heavy.
    2x8" will bundle the highs.
    It'll take you more than a year to design and build this thing, if you're looking for perfection and don't have all day, everyday.
    In the end very expensive... drivers, woodworking, filters, hardware, etc.
  18. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    A full range band-pass style speaker is anything but full range, nor does it have predictable response suitable for bass guitar. Besides, the phase response combined with the sub cabinet (there will be some significant overlap at the low end if the bandpass "full range" box is run full range) will result in significant phase interactions (peaks plus dips).

    There is a reason why you don't see many attempts at band pass boxes intended for high quality bass guitar.
    Al Kraft likes this.
  19. basscooker

    basscooker Commercial User

    Apr 11, 2010
    cincy ky
    Owner, ChopShopAmps
    Derailing my own thread for a second.
    Is there a design graveyard? Like a collection of "here's the idea, here's why it won't work" pages for folks without a familiarity with the history of the progression of speaker design?

    That would be handy.

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