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fEarful™ 12/6 & 15/6 enclosure designs - FREE!

Discussion in 'Amps and Cabs [BG]' started by greenboy, Jan 21, 2009.


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  1. davio

    davio

    Nov 2, 2006
    Boston, MA
    IIRC, gb bi-amps it (or is it the LSx1503 with the KL3015LF?...either way) and only puts in about 330W/side and reports to get plenty of hi-fi booty.

    I'm sure an El Whappo homebrew would be possible, but why when you can have a fEarful 15 and fEarful 12 stack and have the modular option for when you don't need so much overkill? Not to mention portability...

    As for the fEarful 12...do you imagine you'd bi-amp that too, gb?
     
  2. rumblinbass

    rumblinbass

    Aug 22, 2003
    Wimberley, TX
    330W per side?...is that for 2 fEarful 15's? I'm curious to find out what is used for the 6" mid-range driver? Something like a GK with a dedicated 50W?
    Or am I on the wrong track?

    Good point with the El Whappo home brew.

    I really like the idea of a fEarful15 and fEarful12 stack!:bassist::D
     
  3. davio

    davio

    Nov 2, 2006
    Boston, MA
    As I understood it, he's using one side of a power amp to put 330W into the 15 and the other side to put the same into the 6" (in actuality it's considerably less than 330W).
     
  4. rumblinbass

    rumblinbass

    Aug 22, 2003
    Wimberley, TX
    :eek:wow
     
  5. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Yo boyos! : }

    I've almost always gigged this driver combination using a V-Bass to drive a teensy tiny QSC DSP-4 for a 630 Hz active crossover (it can also provide other functions such as compression, limiting, EQ, etc etc). The DSP-4 feeds my 14-pound single-space Peavey DPC 1400X which has 330 watts or so at 8 ohms, per side, on tap. So during attacks on a loud gig my 3015LF will sometimes see 330 watts.

    [​IMG]
    [​IMG]

    Both power amp gain controls are set to the same detent about halfways up, so if a signal actually has enough content above 630 Hz, the 18 Sound 6ND410 could be hit by up to 330 watts as well. And it can easily take it in bursts - even 480 watt transients seem to be no problem. But realistically, even a mid-heavy signal has only maybe 1/3 as much energy above the crossover point as below it, so it's very seldom the 6ND410 would see even 120 watts. In fact I also have to pad the 18 Sound mid cone back 3 deciBels to match sensitivities between drivers so that means maybe 60 watts tops unless I'm layering V-Bass distorted guitar with V-Bass bass and they are both really maxed.

    A couple gigs I used the same strategy, but this time with a second 3015LF cab and a QSC PLX3402 - 1100 to 1250 watts potentially to the dual 3015LFs, and 700-800 watts potentially to the 6ND410. No problems whatsoever, other than I could only turn it up around halfways on a song or two near the end of the last set, and I did draw dirty looks from band members ; } EDIT: ...Actually the fEarful 15/6 can deal just fine all alone with a 800-watts per side amp, BTW - even with a huge squarewave synthbass layer ripping sky from 27 Hz and upwards.

    I'd do the same with a 3012LF/6ND410 fEarful as well - though I'd have to pad the midrange cone back another 2 or 3 dB to balance things. But actually, if I didn't have the little QSC DSP wonder to use as an SMS (Speaker Management System) I'd be more than comfortable with a passive crossover.

    [​IMG]
     
  6. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    As for "ripoff" Accugrooves, either fEarful 15/6 or fEarful 12/6 can be built with a tweeter, and there's no reason to think the Accugroove could keep up or sound as even ; }
     
  7. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Seems to me that earlier someone had asked about a 212 with both 3012HO and 3012LF woofers. And an ever-so-popular vehicle analogy came to mind after I had answered - you know: the kind where it makes some sense though there's no direct one-to-one correspondence between the two situations ; }

    Anyway. Say you have a 4-wheel drive. You put one size of wheels/tires on the front and another size on the rear. Everything's fine when conditions are easy. You can drive on roads and nothing's being stressed. But then you get into terrain and conditions where you actually NEED to use the potential of your vehicle.

    So you shift into 4WD. Here's where you realize that the two sizes weren't such a good idea. You feel the binding and the stress on the drivetrain as one set of wheels/tires attempts to keep up with the other and can't. You've got different amounts of distance each set wants to travel at a given RPM. Things are bucking and grinding and something's got to give.

    In the case of the two woofers, that 3012HO is the weak link in the drive train. It's not going to be able to deal with the demands that the 3012LF can easily meet.
     
  8. bongomania

    bongomania Gold Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    GB, have you had any thoughts yet about a double-fE 12? I.e. 2x12's and 2x6's in a vertically-aligned cab?
     
  9. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Actually I was thinking about it last night. But I'm wondering if I am motivated enough to learn a new software to make it easier. I can do the designs and calcs on paper in no time, but it takes a lot of time doing the finalized plans considering I probably won't ever use most of what I've come up with.

    In the case of a fEarful™ 212/6 (I'd just use ONE 18 Sound 6ND410 instead of TWO Alpha-6A and feel great about it), for my own needs I'd just as soon have a 3015LF version and a 3012LF version instead - for when I actually need to go to LUDICROUS SPEED. The modularity is higher and so is the output.

    [​IMG]
     
  10. davio

    davio

    Nov 2, 2006
    Boston, MA
    Yo GB! Any word on the finalized design?
     
  11. Colonel_Claypoo

    Colonel_Claypoo Steve Harris nut

    Oct 24, 2007
    Germany
    +1 can't wait.
     
  12. Mixi

    Mixi

    Apr 9, 2007
    Hi!

    Im building fEarful 15"/6" using 3015F and 18 Sound 6ND410. Right now im slighly having problems with designin passive crossover. I would like to use passive crossover to save some money and instead of buying stereo amp, active crossover I could use something like little mark II and save in weight and money.

    Ive tried to read a lot of information about designin passive crossovers but the problem is that I dont have all the eqvuipment needed to mesure speakers resistance at different frequencies.

    So what crossover point would you choose and which order? And also would someone have a change to measure speakers resistances at those frequencies?

    Thanks!

    Mikko
     
  13. greenboy

    greenboy

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

    For the actual impedance figures you'd want to use for the crossover calculator, just look at the driver datasheets for each driver. On the 18 Sound 6ND410 there's a graph labeled FREE AIR IMPEDANCE MAGNITUDE CURVE, and on the 3015LF sheet the light grey curve on the main graph represents this.

    Once you choose a low pass crossover point for the woofer (say 710 Hz) then you see that the grey line is at just above 9 ohms for the 3015LF.

    Then say you want an overlap to make up for the 6ND410's dropoff in a sealed box as it gets into lower frequencies. Say you choose 630 Hz as the high pass point (both those figures have worked very welll for me as an overlap). The other graph on the 18 Sound sheet shows that at 630 Hz the impedance is about 7.7 ohms.

    So, woofer lowpass is 710 Hz at 9.3 ohms, midrange cone is 630 Hz at 7.7 ohms. But what slope?

    I do this with an electronic crossover so I don't worry about passive parts count - I just choose a steep Linkwitz-Riley 4th-order (24 dB per octave) slope. LR crossovers sum the two drivers flat unlike Butterworth (BW) which tend toward a 3 dB hump in the crossover region (sometimes you can use this to your advantage but not here really). LR also exhibits less lobing which I won't get into here but it's beneficial.

    But LR24 takes a lot of components in passive implementation so you may want to consider LR12 (2nd order) instead. That'll give a little less protection to the mid cone but unless you are running incredible wattage that 18 Sound can take it. So don't worry here. The imaging of a shallower slope where both drivers are reproducing isn't much of a problem because the woofer and midrange cone are roughly vertical to each other, so LR12 should be fine here.

    If you decide you are hearing too much or too little in the crossover region the easy fix is just to move the overlap of the midrange high pass a little lower if you want more "honk", say to 560 Hz. Or correspondingly, if you want a little less honk, move the woofer lowpass down to 630 Hz or so.

    It may take a couple additional components to tune the circuit to your ear as described in that last paragraph, but first accustomize to the initial design. Listen, play, and use the head's EQ before turning into a "component tweakaholic."

    Best of luck, man!
     
    Triad likes this.
  14. Mixi

    Mixi

    Apr 9, 2007
    Thanks greenboy! That helps a lot!

    Edit: When using this calculator http://www.diyaudioandvideo.com/Calculator/XOver/ and calculating low pass filter for woofer should I say that tweeter Impedance is about 7.7 ohms @ 710hz (as FREE AIR IMPEDANCE MAGNITUDE CURVE shows) and when calculating high pass filter for midrange cone is woofer's impedance about 9.6ohm @ 630hz (as gray curve on to main graph represents?)

    And btw Im not sure that do I understand the graph right but 3015lf's impedance @ 630hz looks more like 11ohms to me?
     
  15. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Oh, BTW: I actively pad the 6ND410 back 3 dB when used with a single 3015LF. That's a real balanced voicing for the cab. So you want to do the same with fixed resistors in the circuit. If you want a brighter default voicing you might want to pad only 2 dB, but really the 3 dB pad in conjunction with the Markbass EQ facilities might be better for getting "your sound" if it is brighter or darker...
     
  16. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    This combination of drivers might sound great with just the Eminence PXB2:500 too.

    [​IMG]

    I've tried mine with the stock crossover from the Carvin LS1503 which is similar and it sounds great. The 18 Sound 6ND410 in a sealed box is remarkably forgiving (and the 3015LF is very amenable to any EQing).
     
  17. Kindness

    Kindness

    Oct 1, 2003
    Chicago
    As you may remember, I've been using an Eminence PXB2:800 for the time being before I start playing with crossover components myself. I've found it to be a really great match, especially in light of how well both drivers do with EQ.
     
  18. Interceptor

    Interceptor Supporting Member

    Mar 29, 2005
    Madison, WI
    I'm in the final planning stages before grabbing the wife's SUV and going on a run to the local wood peddler. 15 + 6 for me. I'm hoping for a 55 pound build, which is a size cabinet I can move. That would drop the cabinet gig load either in half (two EV cabs at 56 pounds each) or by around 40 pounds over my EBS 611. That and the 15 + 6 ought to crush either of them in stage volume. Worth the effort!

    One of the last parts I'm mulling is passive or active crossover. I've got the amp covered to go active (QSC PLX1602) a preamp I like and rolling up an active crossover wouldn't take me more than an evening or two. Then there is the thought of using a passive; it would allow me to take advantage of one of those really light weight heads. And backup amplification.

    OK, what am I missing?

    Either way, I'll publish here what ever I design.
     
  19. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    And if you are playing a lot of smaller, clumsily-shaped stages like I do, the way better dispersion characteristics will make stage mixes a lot more pleasurable for you, and nicer for your bandmates because they'll get some note defintion and richness, but not the harshness that pisses 'em off.

    Cool - when competent DIY stuff is shared all can benefit, even if they don't build it!

    Myself, I'll probably roll a passive with bypass, but with biamping I can get a sound quality that's stellar and I'm already set up for it. I like the way you can hammer the woofer to the limit and get that rich harmonic distortion in the lower areas, but the midrange and treble continue to have pristine clarity and accuracy. The real-world headroom is unbelievable!
     
  20. greenboy

    greenboy

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

    I keep staggering back and forth on finalized size and shape. It's tough because if it were going into my rig it'd be easy to make the choice.

    But it probably isn't. So I'm trying to figure out the best way to serve a lot of potential users. I have these conflicting user profiles of guys who want the box small as possible without tossing away the advantages of the driver, players who would want to stack a couple - some of those using only one midrange cone and leave the other box just a woofer, players who might be thinking subwoofer, players who would like only one box and would like it to be tall enough not to always need tilting or putting it up on a stand, etc. I've got iterations of several of each. I've even considered a tiltback though I said I wouldn't.

    Arrrrggh!

    Oh, well. It'll be awhile before the driver is readily available.
     



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