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DIY 2x15 guidance

Discussion in 'Amps and Cabs [BG]' started by Curtybob, Sep 7, 2008.

  1. Curtybob


    Jun 2, 2007
    Jackson, MO
    I'm seriously considering building a 215, and in doing some "research e-shopping", I ran across some Soundtech crossovers on Parts Express that seemed ok for what I want, but I wanted to know if anyone had any opinions on them.


    I've drawn up plans (even though maybe I am the only one who can make sense out of them), and I drew them around what I think I understand :)confused:) about the KappaLite 3015LF.

    Anyway, for the time being, I'll probably just run it with the 15's and no crossover or mid-driver. I'm sure that I'll need to add it, but I figured I could do that after a few weeks to make sure I like the way the cab sounded.

    Basically, the cab would wind up with about 11.235 cu.ft of internal volume after deducting the bracing (will be horrible overkill, but it will be stiff) and displacement of the speakers, and for what will be the seperate wooden compartment for the mid. I think I am aiming for a 43hz tuning (two 6" diameter x 2.93" ports at the bottom of the baffle).

    Anyway, back to the questions.... like I said, does anyone have any opinions on the Soundtech crossovers? My band has two older Sountech cabs that we've had great luck with. But I have no idea if it is just luck, or if they actually make decent stuff.

    And second, am I going wrong with the 3015LF? Is there another driver I should look into?
  2. that is gonna be one huge cab. just out of curiosity, what are your exterior dimensions? have you looked at the 3015 non-LF? you can get by with a smaller cab volume and out perform most other 15 or 215 cabs if done properly. it is possible to tune higher, too with the 3015s, 50-55hz. i put 2 3015s in an OLD peavey 215 cab, the short version, and they sound great. that was with about 2.6-ish cu.ft. per driver. they'd probably sit better in about 3.0-3.5, but work fine for me. my cab dimensions are approx. 42H x 25W x 13D. cant help on the crossovers or mid, sorry, no experience there, but i have read around here that if you really want that set up, you may be set with only one 3015LF. good luck!
  3. Curtybob


    Jun 2, 2007
    Jackson, MO
    I'm making it 48x24x24 finished exterior (corner cover to corner cover). Pretty much the same size as an 8x10, but deeper. I'm a commercial carpenter, so I'm probably killing it with the bracing.... but at least I know it won't flex.

    I'm sure it will probably be heavy, but the way my cabs get handled, it doesn't matter much. It'll probably spend most of the time in the practice space. And if it goes anywhere, it is getting the fridge-style towel rack handle, and some heavy duty fixed casters. Then, getting it into the pickup or on the trailer is fairly easy.

    But, the LF/non-LF thing that you mentioned is what I'm wondering about. I guess what I am after is versatility. I like (and expect to play) everything from Metal to dub. I just remembered seeing alot of people bragging on the 3015LF. But honestly, something with a bit more wallet-friendly price would be nice.
  4. doctec


    Mar 22, 2005
    Beaverton, Oregon
    I know you're asking specifically about crossovers, but when I saw the 3015LF reference, I felt compelled to chime in :)

    If you like the sound of 15's, the 3015LF is a great choice. A while back I built two TL-606 cabinets and loaded them with 3015LFs, with excellent results. I know several other folks on this list have done the same.

    The TL-606 is a proven design that's exceptionally easy to build at home. I like the flexibility of having two 1x15 cabs rather than a single 2x15 (been there - done that), but that's up to you. You could easily modify the published plans to build a 2x15 box.

    FWIW, I played an outdoor gig last night (kick drum in the PA, but not bass) with my current rig. I've got an X2 wireless and when I went out front while we were playing, I couldn't have been happier with my bass sound :) My current amp rig is an Alembic F1-X preamp running bi-amp mode into a PLX 3402 driving an Avatar B410 on the high end and a single TL-606 cab (3015LF) on lows crossed at about 80Hz. The second TL-606 would have been cool, but there wasn't room in the van :)

    Anyway, here's the link to the TL-606 (and other) plans for simple and effective speaker boxes:

    http://archives.telex.com/archives/EV/Builders Plans
  5. Curtybob


    Jun 2, 2007
    Jackson, MO
    Actually, I thought about building one of those as a backup plan of sorts. That way if I didn't like the big cab, I could do a quick swap and be back in the money.... so to speak. Then my drummer said that it might work well as a bass bin. So, I guess two backup plans are good. The wood costs aren't a problem, I usually have plenty of large scrap from building cabinets on-site (got 2 sheets of nice 13 ply right now), so except for invested time and tool wear, it won't cost much to make any cab I think will fit.

    The speakers and hardware, however.... that's not stuff I have laying around (except a nice18" long, 1 3/8" stainless grab-bar that will make a killer handle).

    Anyway, I definitely appreciate the input. I have no clue what I am getting into with this stuff. I built my 6x10, but I just got lucky that it sounds halfway decent. Because I just started tossing it together and next thing you knew, it made noise. I don't think I'll get that lucky again. This time, I'm going at it with a plan... or two.
  6. gerryjazzman

    gerryjazzman Supporting Member

    Dec 31, 2006
    New Jersey
    The thing with the 3015LF is that it's more of a woofer than a "full range". It's a kickass driver though. I'm in the process of building a Bill Fitzmaurice Omni 15 Tallboy that uses one. But that's a three way design with midrange and tweeter. I think Greenboy's Fearful design (also a 3-way) uses one, and some are retrofitting them into the Carvin LS1503 (again a 3-way). You probably won't be happy with the sound (lots of bass but not so great on the mid to upper mids) unless you cross it over to a midrange probably somewhere between 700 Hz and 1Khz, certainly no higher than 1 kHz. You want to use a crossover but what kind of driver are you crossing over to? A 3015 would be better in this regard, or a Deltalite II-2515 letting you crossover somewhat higher, up to maybe 2Khz max.
  7. mrkreuzschlitz


    Jun 30, 2008
    Dacula, GA
    Wait, I'm not a genius at cab design, but what if you got one 3015 non-lf and threw it in the top of the cab, then the lf version in the bottom? Its just an idea.
  8. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Not a good one, I'm afraid. The 3015 will be farting out while the 3015LF is still coasting along at half capacity.

    The 3015LF is fine in 6 cu ft, and with its output capabilities no one needs more than one. But it's next to useless without a midrange driver to cover above 800 Hz or so.
  9. Curtybob


    Jun 2, 2007
    Jackson, MO
    Right on. So, the 3015LF is not what I'm looking for. That's cool. So, any other drivers that would get me up to acceptable range and still hold it down low? Or is the 3015 and 2515 where the pudding's probably gonna be? But yes, the plan is still to utilize a crossover and mid. I was thinking of a 5 or 6 inch driver, as I'm not a fan of the super zingy tweeter sound.

    And, I know it goes against the whole lightweight craze, but 2x15 and a big cab kinda appeals to me. I guess I just have a soft spot for the look of a nice 215.
  10. I built a pair of 1x15's around 5 years ago. STill use 'em.

    I used the Eminence B15's. They're only 300w - so they may do the job for you - unless you need more volume (or wanna get chucked out of pubs :meh:).
    I tuned mine at 40Hz - and whilst that's probably a bit low, I do play down tuned exclusively, so having the resonant frequency bloom at the 7th fret on the "A" string is a really useful design artifact.(but it's not an A for me, actually an F)
    I didn't design it with that in mind - just a lucky fluke!
  11. Vinyl is making a comeback, and so are 215s (maybe?) :)

    Running a mid should work great - the 3015LF are excellent drivers...your cab will def need lots of bracing because my carvin cab when loaded with these was shaking the drivers out of their baffles. I have to velcro my amp to the top of the cab.

    You can use an eminence crossover at 800hz. They are 8ohm crossovers - so one woofer/one mid will connect to one crossover.

    I got 2 crossovers for my cab and wired them in parallel from the jack. The cab has two mids. If you are using only one mid, then use a second crossover just as a low pass, or just let it run full range.

    You may want to consider an access hatch so you can change the xover bulbs if they fail (rather than having to remove a driver).

    Alternatively, build a little 'mid' box for on top...with xovers in, and run the lowpassed signal from an output on the little box to the big one. That way you can also run the big box full range with no crossovers. Thats an idea I had that might be quite practical (allows any cab to use for woofdom with the mids).

    Heres my customized carvin 215 after the bracing is in...you can see one of the crossovers...


  12. How hard are you going to hit the cabinet? If you are hitting with 1000 watts of compressed signal (like it if was a PA sub) 600 watts RMS may not be enough. I smoked the carvins original crossover after an hour of quite heavy use.

    External active x-over is another way to go, though unless you have an amp with xover built in would mean having a rack.

  13. It will be a pretty big cab - stairs could be a pain, flat ground with a dolley should be fine.

    Its worth nothing as well that the 3015LF has so much travel that dialing in gobs of low end is quite possible....amp headroom allowing. I havn't been able to bottom out the 3015LF's.

    So a smaller cab with 3015LFs and some low end EQ may work just as well as a bigger cab with flat EQ.

  14. I'd go with two x 8" or three x 6". Those 15's will be moving some air through those ports. If your are set on two 6" then maybe try some precision ports.
  15. gerryjazzman

    gerryjazzman Supporting Member

    Dec 31, 2006
    New Jersey
    OR.... Maybe two 1x15 cabs, stackable each with a 3015LF and a midrange. Make them mirror images so you can stack them with the midranges in the middle, as close as possible so you have essentially a D'Appolito arrangement. If you only find you need one midrange you could stack them the other way with a midrange on top to get it more at ear level and turn off the bottom one. You'll be able to use 3015LFs in reasonable size 1x15 cabinets for transportability, and have the ability to scale your setup (1 or 2).
  16. Curtybob


    Jun 2, 2007
    Jackson, MO
    Alright. Change in plans... sorta. I'm gonna keep pretty much the same cab design, but replace the 3015LF's with the 3015 non-LF's. Unless I'm missing something, it can be a direct swap... cab tuning and all. I still have to figure out what frequency to crossover at (maybe I don't have to with the 3015?), and then what mid driver would suit this box. I like the thought of using a 6" rather than a horn.... but I guess we'll see.
  17. greenboy


    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    I've just skimmed, but even for 3015LF drivers, you don't need more than around 3.8 cf NET ( a lot of people underestimate, however, how much internal volume is subtracted by drivers, bracing, and sufficient porting, and forget to do their measurement inside the cab which allows for panel thickness and grille setback) even with a low B or A. And for 3015 non-LF, that's TOO MUCH. You are just making a lot of weight and bulk, and for the 3015 it'll actually detract from cab performance.

    You don't HAVE to cross over. With any woofer. You do it because you think you can get a better tonal footprint, and better performance... Usually overlooked here, the improvement in dispersion/polar/off-axis response in the midrange alone is worth the effort, especially on smaller stages where the stage mix may be forming the FOH mix as well.

    By far the best 6" driver for this is the 18 Sound 6ND410. More sensitive/louder, least jagged frequency response, great power handling, superior off-axis performance... even a lot of slap players would never miss a tweeter if this bad mutha was doing everything north of 500-800 Hz. If you aren't in the US, Beyma makes the 605ND, another neo driver that isn't maybe quite as good but costs less in many countries.

    There are cheaper mids, but one of these will make 'em seem like chopped liver, and it weighs around half of what most of them weigh (2.75 pounds for the 18 Sound), and does twice as much. Since so much of the bass tone, detail, and articulation is in the midrange, it's a BARGAIN to get performance like this!
  18. qts


    May 15, 2006
    Hi there,
    I know that you guys are worship this driver as the winner because of several reasons, weight, sensitivity, small cabsize, etc.
    Personally, i will use this driver if i only need a maximum power between say ~300- 450watts on stage, as a backline monitor.
    I know, this driver is the only one in the Eminence series who can take a full 450 without exeeding Xmax.

    My question to you is; If i need just say about 200watts
    [max], which 15" driver would you recommend?
    What about the D15LF, CB15,K15LF
  19. greenboy


    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    I really don't care about the wattage a head or separates rack is rated at (not that the number means you are always using that amount of amp output ANYWAY). I want the driver I think is best for the cab design I've chosen. The newer Em neo stuff seems to have advanced in all the right ways and it works well at any wattage within reason.

    It's a matter of time before other product niches are filled with the same R&D - the 12" versions that should be out by next year are likely to be big improvements for their categories as well.
  20. Curtybob


    Jun 2, 2007
    Jackson, MO
    Awesome. I can knock the internal down a bit. What I really wanted was a cab that's comparable in size to an 8x10. Partly to get the mid up closer to where it will do me some good, and partly for the visual aspect. Sure... overkill. I'm okay with having more than I need. Even if it's WAAAAAY more than I need.

    I tried to cover everything as far as internal volume went. I can't swear that I didn't make any mistakes, but I think I am very close for the bracing, ports, and speakers. I was kinda thinking I could fine tune when the cab is done, and I can get real-life measurements on everything.

    For the 18 Sound 6"... will one keep up with two 3015's? From what I think I understand it should, but better safe than sorry with a $135 driver.

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