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DIY bass cab

Discussion in 'Amps and Cabs [BG]' started by jackn1202, Apr 15, 2018 at 3:30 PM.

  1. jackn1202


    Feb 14, 2018
    I'm on a tight budget here, but I had an idea that's either insane or brilliant. I was given a broken home theater subwoofer a little while back, and I wasn't really sure what to do with it. I messed with it enough to figure out that the speaker cone is good, but the rest of the electronics are pretty knackered. So here's my idea: can I take all the electronics out of the cab except the speaker cone, solder on an input jack, and use it as a bass cab? I'd buy (or build) a head for it, but this would help me cut back on costs. It's a big ol' boy, called a Miller & Kreisel V-125. That company went out of business years ago, but specs for it can still be found. Any input or tips are welcome.
  2. I think it's unlikely to work well with the speaker that's in it.
    spaz21387 and saabfender like this.
  3. I haven't googled specs but make it a small bass head or the speaker will likely be out of its depth with bass guitar. Probably not the best of tones either but Frankenrigs are fun anyway.
    spaz21387 likes this.
  4. I wouldn't make plans to play Bob's Bar'n'grill with it either.
    spaz21387 likes this.
  5. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Probably not going to like the sound of that speaker, VERY dark, 4 ohm (IIRC) and low efficiency (in the high 80's).

    Also, they typically rated using "peak power", so they would require de-rating the power handling by at least 50%.
  6. You want to play a bass, into only a sub-bass woofer?
    Would you play a bass into only a tweeter?
    Same difference.
    Use the right tools for the job.

    It may seem counter intuitive, but doing a DIY to save money, rarely ever works out to actually save money.
    In your case, you end up with a cab that sucks all the power from your amp, to move the speaker cone in a fairly non-audible fashion. Or at least in a manner that doesn't correlate well to the bass.

    Bass speaker/cab design is really a science. Guitars and subwoofers can both get away with sticking something in a box and throwing power at it. Amplifying the electric bass is much more of a balancing act.
    To do justice to the usable range of frequencies, the bass requires nearly a full fidelity system fine tuned for the special needs of the bass.

    As long as all of this is clear to you, and you know that it's just an experiment going in, one that might work, or might not, then that's fine. But if you plan on this being your main player, and it is important that it sound right, you are more likely to be disappointed than not.
  7. Coolhandjjl

    Coolhandjjl Supporting Member

    Oct 13, 2010
    If you're on a limited budget, look for a Peavey cab on CL. DIY cab builds are never the low cost option.
  8. Pug the Pig

    Pug the Pig SUSPENDED

    Mar 21, 2018
    I've built up cabs, but generally from stuff that started life as bass gear, like he says, look in the small ads..even if you get an empty cab, then a speaker from elsewhere....
    I have an old peavey pa cab that's very sturdy and a handy size into which I put one of those 15" aluminium cone (allegedly 600w) speakers, that works fine, and didn't cost much to assemble.
    1. You have been given a broken home theater sub-woofer, whose frequency response is probably < 1/5 of what bass guitar needs.
    2. You have no amp.
    3. You mentioned building an amplifier to save costs. It won't.
    These are indications of a very limited budget, but by someone who likes to mess with gear.

    If have any serious notions about playing bass guitar:
    1. What ever you buy at this point you will not keep.
    2. Save up, save time, and buy used.
    3. Buy something reliable, something pedestrian (inexpensive), something everybody buys and sells - perhaps something like a Peavey combo.
    If OTOH your preference runs to messing with gear, have at it. Add jacks and build amps.
    Coolhandjjl and mexicanyella like this.
  9. JimChjones


    Aug 6, 2017
    SE England
    Its kinda hard to argue with free, and its going to cost nearly nothing to try, but if Mr Horse thinks its going to be dark I'm sure he's right. The real killer is if its 4ohm as he describes. 8 ohm might make an extension cab for a 50ish 1*10 combo to add a little bit of extra thump (assuming the combo amp is rated for 4ohm and has an 8ohm driver), but otherwise...

    What I wouldn't do is buy or build a head for it, unless I was confident I could afford to buy another cabinet if/when the lashup sucked. Improvising stuff is kinda fun, but these days there's so much goodish secondhand kit available so cheaply that its almost impossible to construct something for less money than waiting a bit for a deal to turn up. Very easy for free enclosure to turn into rather expensive rig.
  10. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    The world is awash with decent used bass cabinets (if you don't mind heavier, larger cabinets) for pennies on the dollar. I don't understand messing with something like this to save money when you can get a better bass cabinet that will work for under a hundred dollars.
    Coolhandjjl and AstroSonic like this.
  11. Probably cost more than a used cab to just make that work well enough to enjoy.
  12. AstroSonic

    AstroSonic Supporting Member

    Dec 10, 2009
    rural New Mexico
    Buy something used that meets your needs. This HT sub would probably have decent low bass, but would lack upper mids and highs. It would also be around 10 db less sensitive than most bass cabs, so it would require around 10 times the power to reach the same volume level. A 500w head would behave like a 50w head into a standard bass cab. And it would run out of power handling well before it was loud enough to do much more than coffee house gigs.
    agedhorse and Old Garage-Bander like this.
  13. jackn1202


    Feb 14, 2018
    Alright, the wise gurus of TB have decided this idea is definitely a flop. Will not attempt. Rest easy my friends.

    And thanks for saving me a few hundred bucks.
    yodedude2 and AstroSonic like this.
  14. jackn1202


    Feb 14, 2018
    Theoretically, could I use the cab, but find a different, specifically bass cab designed speaker cone to put in it? I understand the speaker's no good, but maybe the cab would be alright... I dunno, lol I do kinda want something personalized and slightly DIY, even if just in appearance. I don't gig at all (I wish though, just don't know anybody :/) so it doesn't need to be amazing, but I do want it decent. If this is still stupid and I'm being hopeful, tell me so.
  15. One of the popular DIY for beginners, or even old hands, is premade sub box from Parts Express that coincidentally is tuned nicely for a few 10" bass speakers to work perfectly as a 110 coffeehouse cab. Something might work in yours with little modification but the ante is raised in construction requirements for a 15. It would be easy to get a buzzfest.

    Cat playhouse?
    jackn1202 likes this.
  16. AstroSonic

    AstroSonic Supporting Member

    Dec 10, 2009
    rural New Mexico
    It appears that you have a cab with close to 2.3 cf internal volume. This cab would work well with either the Eminence Deltalite 2512 II or the Eminence Basslite S2012. The 2512 costs more but has higher power handling and is a little more sensitive. The S2012 cost less and has more upper mids presence, but handles less power. Both would require a ported cab, so you would need to install a port of the correct diameter and length for 45-55 Hz tuning. You'll also want to install a jack plate with a female speakon or a 1/4 inch phone jack.
    jackn1202 likes this.
  17. jackn1202


    Feb 14, 2018
    What do you mean "ported cab"?
  18. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Isn't that cabinet particle board? Not a good choice for anything being moved more than once or twice.
  19. Ports let air in and out of the box and tune the space to work in bass reflex mode.