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Tweeter power for bass cab

Discussion in 'Amps and Cabs [BG]' started by mariano90, Dec 29, 2017.

  1. mariano90


    Dec 29, 2017
    Hi everybody, I'm a newbie in this forum hope I'll be clear with my concern.
    The thing is I've recently bought a tc electronics bh800, an 800watts bass amp with no speakers and now I'm hoping to design one.
    My idea is to build a 2x10" plus a tweeter cab. Both 10" speakers are 350 watts each, so I guess those will fit perfectly for the 800 watts the amp gives. But I've no idea which tweeter I should use, for what I've seen the most common thing to choose is a 1" tweeter, but what power?
    This are the 10" speakers

    B&C Speakers

    Then b&c has only a 50watts 1" tweeter to offer, will that be enough?
    Can anybody please help this poor ignorant soul?
    Thanks in advance
  2. lz4005


    Oct 22, 2013
    The kind of tweeter you need depends on what frequency curve you're going for, what kind of crossover you're using, how much space you have in the cab, etc.
  3. Rick James

    Rick James

    Feb 24, 2007
    New Jersey
    You won't want to hear this, but if you have to ask such a basic question you shouldn't be thinking about designing your own cab. For instance, the woofers you want to use are a very poor choice for electric bass. There's a lot more to choosing a woofer than inches and watts. Use a tested and tried design, with the drivers recommended for it.
    Al Kraft, Lvjoebass, Gizmot and 5 others like this.
  4. mariano90


    Dec 29, 2017
    Hello Iz, thanks for replying. I like my sound to be quite vintage, more like a jazz player, i'm not much into bright sounds, i like it rather warm (hope that was a clear description). With this in mind, i don't have much use for a tweeter, but i want it to have a greater sound flexibility. So if you could help me once more, which crossover curve you recomend? The LF driver extends up to 4Khz, so maybe a crossover starting at this freq would be suitable?
  5. mariano90


    Dec 29, 2017
    Don't worry about me not wanting to hear something like that, on the contrary, it helps a lot. I choose those drivers taking also in consideratioin the 100db sensitivity and it's quality as well. Then I plan to use its
    Thiele-Small parameters as inputs to a software than'll give me an appropriate design for the cab, plus the tweeter information. What i do not know is if the allocation for the crossover board will disturb the cab design and its audio response
  6. Rick James

    Rick James

    Feb 24, 2007
    New Jersey
    Another example of why you shouldn't be designing you own cab. Those woofers extend to 4 khz, but only directly in front of them. The crossover frequency should be no higher than where the 30 degree off-axis response is no more than 6 db down from the axial response, otherwise you have drastic changes in tone as you move across the audience.
    That's backwards. You choose the driver based on how it models. That would tell you that this driver has 100 db sensitivity in the mids, but it has almost no low end at all. Also, designing a cab is a lot more than knowing the internal volume and making a box that size.
    FenderB likes this.
  7. basscooker

    basscooker Commercial User

    Apr 11, 2010
    cincy ky
    Owner, ChopShopAmps
    If you're only talking about a few cubic inches of volume it isn't a huge concern. Once you start getting port volume, bracing volume and other details adding up to like 0.2 or more (cubic feet), then you need to factor that in.

    How far down in dB is that 4k top end? If it's like -6dB I'd suggest setting the hpf lower. Are you building the crossover or buying? Many very successfully smooth crossovers are simply carefully chosen high pass filters, and the woofers are allowed to run "wide open" to roll off naturally.
  8. nbsipics

    nbsipics It's the Bass that makes them Dance Gold Supporting Member

    Apr 8, 2016
    Welcome to talk bass.

    Now: Put a value to your time. At only $10 an hour you will have maybe $300 in? Plus wood, drivers, etc.

    Save time and money and grief, and buy a Berg NV115. Done.
    Plastalmonus likes this.
  9. Coolhandjjl

    Coolhandjjl Supporting Member

    Oct 13, 2010
    Some designers spec a mid-range driver rather than a tweeter. As mentioned, all depends on what you want the top end reproduction limit to be, and where you want to cross-over.
  10. Inara

    Inara Fierce Fun Fretless Female Supporting Member

    Jun 12, 2017
    Seattle, WA USA
    If you'll look at those very Thiele-Small parameters you mention, you'll see that the xmax for your chosen driver is only 1.5mm. That's horrible for bass instrument amplification, just looking at that one parameter. In any conceivable bass cabinet design you'll hit the mechanical limits of the driver at far far lower wattage than the 350 watts thermal rating that seems so attractive. I'd be surprised if the drivers would handle 50 watts at bass guitar frequencies. At the very least you'll want 3 or 3.5mm, and I prefer over 4mm.
  11. EricssonB


    Apr 5, 2011
    CoSpgs, CO.
    Welcome to TB.

    Yeah though, I've had it in mind many times to build cabs or whatever, and I always concluded that designing specifications isn't something I have the time or resources to pursue. I am a DIYer most of the time, but almost everything I end up doing is 90% plagiarized, 5% modified and 5% improvised-once-I-realized-I-messed-something-up.

    For instance, I have a project on the books to build a new enclosure for my car's subs. Do I need 2x12" subs in my car? No. Do I miss having a trunk in my SUV? Every. Single. Day.

    ...but I also got them and a 1600W amp for a really good deal and I'd be happier with that second sub under my computer desk. Design two enclosures? No -- people have been designing and redesigning cabinets professionally and I would rather copy a tried-and-tested design and be done with it.

    Edit: this conversation has been floating around TB for like forever.
    Last edited: Dec 29, 2017
  12. mariano90


    Dec 29, 2017
    Ok everybody, I've got the point. Thanks a lot, i'll try to find some useful plans or see if i can buy a cab. If anybody has or knows where i can find plans to build a cab for an 800watts amp please let me know
  13. telecopy


    Dec 6, 2009
    Personally I would just get the TC cab(s) designed for their amp and save yourself the headache and expense of making a cab. I had big aspirations of doing this at times and I'm glad I just purchased properly engineered and constructed bass cabs.
  14. Kmonk


    Oct 18, 2012
    South Shore, Massachusetts
    Endorsing Artist: Fender, Spector, Ampeg, Curt Mangan, Nordstrand Pickups, Korg , Conquest Sound
    I'm surprised nobody else has mentioned this but the first thing you have to do is check the impedance that your amp can handle. Then you can choose which speakers to buy and how to wire the cab. Personally, I would just but a 2x10 cab.
  15. Delete the tweeter. Problem solved.
  16. FenderB


    Mar 28, 2016
    Findlay, Ohio
    Rick you seem to have this stuff down pat so why don't you help him?
  17. Rick James

    Rick James

    Feb 24, 2007
    New Jersey
    To be a good speaker designer you need to understand the theory, you need to be a structural engineer, and you need to be an expert woodworker. I'm OK with the theory, but I'm not a structural engineer, and my expertise in woodworking only extends to being able to follow plans, not to create them. That's why my cabs are BFM designs. Since the OP doesn't understand the theory and probably isn't a structural engineer either telling him that he shouldn't try to design his own cab is helping him.
  18. singlemalt

    singlemalt Supporting Member

    Dec 15, 2007
    White Salmon, WA
    Go over to Greenboy’s website, check out the free, detailed plans for building a fEarful cab.
    greenboy™ enclosures - Index page
    Pick a plan, build a sure thing, proven cabinet. Maybe make a small donation to support the website and say “thanks!”

    If you like DIY, but don’t want to just throw cash after guesswork and speculation, fEarful is the ticket.

    There’s an encylopedic thread on Greenboys’s cabs going back almost a decade, right here on TB.

    But you could download the plans and build a cab faster than plowing through the history.

    My “bang for the buck “ fEarful is the 12/6 cube with the alpha 6 mid, no tweet, and simple CBG crossover.

    I’d been messing around with building cabs for a while, and I was pretty stoked with my TL-606’s and 3015’s. The fEarfuls took me to another level.

    Building fEarfuls are a great way to scratch the DIY itch, and build top quality cabs for a reasonable price. Have fun!
    Last edited: Dec 29, 2017
  19. GrapeBass


    Jun 10, 2004
    Graphic designer: Yorkville Sound
    Honestly, I don’t understand the need for a tweeter on a bass cab ever, especially in a band situation. I’ve never used a cab that ever needed extended highs, ever.

    And if you do want to use a hf driver (tweeter) make sure you use a proper crossover and compression driver not a piezo.
    alesreaper9, Amory2113 and Korladis like this.
  20. Hounddog409


    Oct 27, 2015
    I think you are in over your head.

    You have to design the cab to match the speakers... cab volumn, ports etc, crossover, etc.

    You will be better served buying cabs. There are screaming deals on the used market.
    Gizmot likes this.

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