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fEarful™ 12/6 & 15/6 enclosure designs - FREE! (Part II)

Discussion in 'Amps and Cabs [BG]' started by Kelly Lee, Apr 3, 2009.


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  1. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    I probably won't finish the fEaRBsub until I have real time and feel for it again. Anyway, it's for either ERB guys tuning lower than B0/A0, or for club PA subwoofer use. The 15/- is a better fit, and stacks to a good height.
     
  2. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Another consideration in doing 15/6 & 15/- is that you need to have low-pass on the 15/- box - yet another reason I am glad to be biamping. And you need to use a higher crossover point as I've said before, if you want the midrange to be protected when you are using serious power to drive the system. I do that easily with an active crossover but with passive, you need to plan ahead and go for at least an 800Hz 3rd order highpass if you are using some real power. 4th order would be better yet (two midranges would be better yet at some point).

    Generally it's a lot easier and safer to do this with biamping when you get into the 15/6 which has woofers a lot more sensitive than the 12/6 has.

    Be warned.
     
  3. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Forgot to mention the other possibility. Get a later Carvin RL115 box (has Speakons) or a Carvin BR115 box and put the 3015LF into that. Almost exactly the same internal volume and tuning as 15/6 - just a smidgeon smaller.
     
  4. knuckle_head

    knuckle_head Commercial User

    Jul 30, 2002
    Seattle
    Owner; Knuckle Guitar Works & Circle K Strings
    When you get steam back - curious as to what can be expected out of the sub.
     
  5. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Hey Skip,

    Same as the fEaRB minus the midrange and tweet, but cased in a modern direct radiator subwoofer form factor (small baffle, deep), stacks with fEaRB to about the same height as two 15/6, but deeper, as to get the bass extension ERB benefits from the additional internal space has to come from somewhere.

    I got to the point that outer dimensions and port was finalized but bracing design needs some real time to do it right.
     
  6. jnewmark

    jnewmark Just wanna play the groove. Supporting Member

    Aug 31, 2006
    Stax 1966
    Play guitar.
    If you were to use the BR115 as a stand alone, would you use the 3015LF or the 3015, with about 800 watts from the amp?
     
  7. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Not really a fEarful question... I wouldn't use the 3015LF as a standalone unless I wanted a real dubby sound. Which I can achieve with a 15/6 anyway, just by using my EQ, and still retain off-axis performance that aids in definition of sound.

    Personally I wouldn't use a 3015 in that large of box because the 3015 xmax is too easy to reach the end of in a larger internal space.

    EDIT: No reason to chase your own tail, really. The Carvin LS1503 net volume is at the upper end of what is superior for the [non-LF] 3105. Tuning is good for that too, though that could be adjusted downward if desired by adding a couple inches of shelf - which would also slightly detract from internal space of course.
     
  8. jnewmark

    jnewmark Just wanna play the groove. Supporting Member

    Aug 31, 2006
    Stax 1966
    Play guitar.
    Thanks. Did'nt mean to derail the thread, and thanks for the edit. :bassist:
     
  9. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    No de-rail, really ; } - and speaking of rails, anybody remember this?:

    [​IMG]

    So I'm contemplating building something like this top-box as a 4-space rackmount unit of the thinnest ply possible, with RACK EARS maybe, to go into a 6-space rack, and leaving room for two more spaces for power amp or whatever. So I get to browsing racks on eBay, when I happen upon this:

    4 Space 10" Deep ~LATCHLESS FLAT LIDS~ 1/4" Rack Case

    1-4latchless10deepfinished.

    Well, In could easily just let this BE the basis for the enclosure - just take the rails out and fill the holes, glue the slightly downsized front lid in from behind as baffle possibly, use the aluminum valence to mount a diamond extrusion grille, and seal the mid and tweet in with a glued panel about 4 inches back from the front with connector cup inset, - and then use the remaining ~ 6" with its back lid, as storage space for cables, straps, etc.

    Cheap, light, could be cool... I've bought a lot from Hybrid Cases in the past, so I'm real comfortable with the quality and pricing.
     
  10. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    BTW, I just snapped one of those up. Easy decision at that price, and since I'd considered doing the fEarful 15/6 in the past using ABS laminates and aluminum extrusions as part of the build. Reliable Hardware whom I've linked many times is one of several sources for this stuff. If it works on racks with decades of roughy use, it should be fine for enclosure exteriors.
     
  11. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    jnewmark,

    I should probably amend my comments on the Carvin RL/BR115 box as a suitable housing for the [non-LF] 3015. If you saw a few inches of shelf depth out of there it gets better.
     
  12. GregBlach

    GregBlach

    Mar 5, 2009
    Denmark
    Build update:

    Managed to put carpet on the 12/- today. For reference I am 182cm tall:

    [​IMG]
     
  13. lo-freq

    lo-freq aka UFO

    Jan 19, 2003
    DFW, Texas
    Sweet!!!
     
  14. vlad335

    vlad335 Supporting Member

    Apr 14, 2003
    Latrobe, PA
    After reading thru the previous thread I must have missed something... I was under the impression that 2 3015LF's were somewhat of a match for 1 6ND410.
    Let me see. A pair of 3015LF's in parallel would be 103.5db while the mid is 102 correct? That is at 1watt/meter. I have 700-800watts at my disposal for the woofers and 200 or so watts for the mid right now. I will be biamping and have a pretty good DSP. Would this not work?
     
  15. lo-freq

    lo-freq aka UFO

    Jan 19, 2003
    DFW, Texas
    Bi-amping: it should not be a problem to get whatever balance you desire, especially with a good DSP used properly.
     
  16. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    I never said that it won't work. I said that a single 6ND410 limits how hard the system can be driven before the two 3105LF are driven to full xmax. How much earlier? That's dependent on crossover frequency and slope, frequency distribution of input signal, and how much output you actually desire above the crossover frequency.

    And to have a nice overall transition and off-axis response below the crossover point, one can only cross over so high... Above a certain point the 3105LF are beaming too much - there's that swiftly ascending peak you see on the 3015LF datasheet that peaks at somewhere around 1200 Hz. You want steep enough lowpass section and low enough crossover point to minimize the effect of that peak's output.

    Finding a nice midrange driver that can even keep up with one high-output driver like the 3015LF is tough enough... until you put the 6ND410 into a horn loaded situation you aren't likely to see a single-driver solution that can keep up with two 3015LF driven to the max if a "flat" output is desired.

    Fortunately, that's a pretty extreme case. I had good luck with some pretty extreme levels - more than I could stand and definitely louder than the very loud two-distorted guitars and a Bonham powerhouse style drummer with huge kit. I was using a PLX 3402 that could potentially supply the 3015LFs with more than 1100-1200 watt crests, and a 750 Hz 4th-order LR crossover.

    With a good horn coming in above the midrange cone, you wouldn't even be able to stand being anywhere near the results ; }
     
  17. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Greg,

    It'll be a pleasure to see your bassface when the drivers are installed ; }
     
  18. Count Bassie

    Count Bassie Supporting Member

    Jun 10, 2006
    Smithfield, RI
    Elementary crossovers-101 student chiming in here with a redundancy- just for my own clarification:

    So you want the crossover to efficiently redistribute the incoming signal from the woofer to the mid-driver at a frequency well before the usefulness of the 3015LF approaches compromise; speaking as far as a general-use bass cab is concerned, right?

    EDIT: After a detailed discussion on all this, I often feel as if there's another 10 feet down to the bottom of this technical barrel! After reading my post again though, I see I've pretty much outlined the purpose of a crossover! So never mind, and thank you!

    I'm much better with a Skilsaw...
     
  19. Swift713

    Swift713

    Dec 4, 2006
    Florence, Ma
    My crossover finally arrived and I'm debating where to mount it. I could hang it off the bracing, screw it to the back panel, or maybe the back of the mid chamber. I think the back of the mid chamber would be hard to access if it needed any service in the future. It just about fills a section of the back panel between the braces but this would displace/preclude the foam there. I'm also wondering if I should put foam on the back of the baffle and mid chamber. Any words of wisdom?
     
  20. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    I think I suggested the side panel, on the same side a tweeter would go, above the upper girdle. EDIT: Depending on size it could also do as well behind the midrange chamber on that side wall.

    For damping, I probably wouldn't bother with the full baffle, just the top of the shelf, and the bottom of the midrange chamber.
     



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