Are these speakers comparable + help identify my exact model (Dr Bass vs FearFUL faceoff!)

Discussion in 'Amps and Cabs [BG]' started by arca_tern, May 6, 2019.

  1. Hey all.
    Have a Dr Bass DRB115 that's heavy (58lbs) but loud enough and sounds good.
    Was wanting to go to something lighter and smaller without losing volume (and perhaps gaining some)
    I found a used Greenboy Fearful 12/6: 36 lbs, has the alpha6 mid driver, no tweeter. Heard nothing but good about these, and the size, weight, price are right.

    I wanted to compare the woofers specs of the two but trouble narrowing down which one is my mine in the DRB. It's 4ohm and is an Eminence Kappa, but says nothing beyond that on the speaker body. Was hard to take a decent photo but found one on the 'net <----<< link

    If it's the kappa 15c (which looks different but is the only 15 4ohm I could find on eminence's site) then I think the relevant specs are:

    Kappa 15c 15inch 4ohm (link)
    Power rating: 450 watts RMS
    Usable Frequency Range 63 Hz - 2.8 kHz
    Sensitivity* 98.1 dB
    Peak Diaphragm Displacement Volume (Vd) 206 cc

    (Of course, those specs for the 15inch may be out to lunch if it's a totally different speaker that what's in my cab)

    Kappalite 3012LF 12inch 8ohm (link)
    Power rating: 450 watts RMS
    Usable Frequency Range 46 Hz - 2 kHz
    Sensitivity* 95.5 dB
    Peak Diaphragm Displacement Volume (Vd) 496 cc

    I'm surprised that the kappalite's sensitivity is only 95.5 dB. Aren't these supposed to put out huge sound? Or is that party due to the greenboy cab design and the dedicated mid?

    At the end of the day I know they'll be different sounding cabs, but wondering if the 12 inch kappalite will be able to have the same volume at the lower spl but higher displacement. Also the wattage they are being fed will be different at the different ohm ratings: the head being used will either be my d800 (800w @ 4 ohm/400 @ 80hm) or a Berg Forte for reference.

    What does the peanut gallery have to say?
    Will the Greenboy be as loud (or more) in a smaller form factor and weight? Anyone able to identify the kappa any better?
  2. Foz


    Jul 26, 2008
    Jax FL USA
    The LF's lower sensitivity arises because it is tested at lower frequencies [usable bandwidth is 46 Hz - 2 kHz versus 63 Hz - 2.8 kHz*] - it's a typical trade off for woofers as making very large wavelengths is generally less efficient mechanically than making short waves= all things being more or less equal when you go for more ability at the low end of the bandwidth your efficiency is reduced.

    *sensitivity is measured in the links you posted as "The average output across the usable frequency range when applying 1W/1m into the nominal impedance. i.e: 2.83V/8Ω...]
    arca_tern likes this.
  3. mmbongo

    mmbongo I have too many basses. Supporting Member

    You kinda answered the question with the Vd spec...the 3012LF moves over TWICE as much air as the 15. That's one reason why so many cab makers use it these days.
    arca_tern likes this.
  4. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    There will be so much power compression on the 4 ohm driver above ~400 watts that imo both drivers need to be compared at ~400 watts. Much of your Sibway's additional power into the single 4 ohm driver is doing nothing except accelerating damage to the driver.

    This helps narrow the gap between the two cabinets considerably.
    Doug Parent and arca_tern like this.
  5. And I

    And I

    Feb 19, 2009
    Witchtown, MA
    the fEARful cabs do sound great and can get as loud as you need them to be for almost all situations. the lower sensitivity rating means they need more power to get there.
    arca_tern likes this.
  6. mmbongo

    mmbongo I have too many basses. Supporting Member

    Also don't know what your budget is, but you should check out the Mesa Subway 115. Very small, very light, and will get your sensitivity back up (98.5db) while still moving tons of air and having a clear mid voicing.
    arca_tern likes this.
  7. It really depends on your EQ demands. I don't think the 15 will keep pace as you crank up with lows. It will get to its xmax with relatively little power and then make a hash of the rest.

    So the question is really how badly have you been abusing the 15 already? Gut feeling is if you haven't been cranking it you would get MOAR from the FF by giving it more loud knob to take advantage of clean power handling.

    By the looks of the Kappa chart you would need a wide high mid EQ chop to the FF to get it to mimic the Kappa + Tweeter cab.
    arca_tern likes this.
  8. Right. Because it can go lower (which takes more power to produce sound) it is rated as less efficient.

    That was sort of my question: does a less sensitive cab that moves more air work out as equivalent? In this case sounds like it does?

    Roger that.

    Yeah I haven’t been abusing it for sure. Been using my ears and never cranking it too hard.
    But what I’m hearing is the greenboy will have more range and match if not exceed my current can (depending on eq)
  9. if you move more air that is more loud, not equivalent. Pushing more power into a more efficient speaker runs away with loudness at low power but piling on the power does not.
    arca_tern likes this.
  10. That makes sense to me. Thanks!
  11. Foz


    Jul 26, 2008
    Jax FL USA
    It is not an apples to apples comparison... The LF version is measured about 1/3rd of an octave lower than its counterpart. If you drive the LF's counterpart with a similar lower bandwidth, at some power level which safe for the LF, the C woofer will get all splodey = zero efficiency. If you limit your input signal to 60-ish Hz or higher per the C version usable bandwidth spec [a HPF will do this and lots of folks use em] then the LF is a less efficient choice, however if you want to have output below 60-ish the LF's counterpart aint tall enough to ride the ride. The ability to yield a strong response very low in the band is something many GB cab users like - if that is your cup of tea is matter for you to decide.