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question about performance...

Discussion in 'Amps and Cabs [BG]' started by dukey donkey, Aug 25, 2012.


  1. if I got 2 cabs rated at 45Hz - 5000Hz and a sensitivity: 96 db
    would they perform well for a bass stack? they are 400 watts rms... 8 ohm cabs... just wondering, because it seems the range would be sufficient, but is 96 db sensitivity a good thing? can someone explain how all of that business works anyway?
     
  2. Stick_Player

    Stick_Player Banned

    Nov 13, 2009
    Somewhere on the Alaska Panhandle (Juneau)
    Endorser: Plants vs. Zombies Pea Shooters
    I believe the formula is ONE Watt produces a 1000Hz. tone (maybe a sine wave?) at one meter from the cabinet.

    This won't tell you the dB of a 40Hz. tone. It's probably considerably less.

    There is a formula for wattage increase to dB increase.

    I'll defer to the acoustical scientists on TB.
     
  3. christw

    christw Get low!

    May 11, 2008
    Dayton OH
    I want to be Tesla (tinkerer at Dayton Amp Co)
    No acoustic scientist here but let me chime in a little bit.

    That's representative of the average efficiency of your cabinets throughout a certain frequency band. The numbers given are usually representative of the top and bottom -6dB points, the frequencies where it's noticeably rolled off in volume. In your case it's that "96 dB @ 1w/1m" sensitivity spec. Bass cabs generally range from 90-107 dB when measured at 1w of power and a distance of 1m but it can be over very different frequency ranges from some very diverse designs making for very different individual voicing. From the sounds of the numbers, the cabs will be able to handle most decent amps but aren't incredibly efficient (loud per watt of input). I like tube amps, so I always shoot for efficient cabinets (higher sensitivity) to get the most volume from my lower powered amps.

    On a related note, it takes ten times the wattage (if the speakers can handle it) to be twice as loud. It's usually easier to add another identical cabinet to get a noticable +3dB of increased loudness with no weird issues going on but you're already there at a total of 99 dB 1w/1m. There are plenty of affordable cabs that can outpace those but really, there's nothing wrong with what you've got.

    My personal vote is to go for Bag End or Genz Benz cabs if you're comfortable going to the used market. Both make cabs that are incredibly loud and sound great. The 2x10 / 4x10 BE stack I had was one of my favorites next to my Genz Benz 610 XB2 I had. Either would blow your ears off with just a 100w amp. :D
     
  4. Same cabs or mixed cabs? Let's leave that issssssssue aside, can we?

    96 dB avergage sensitivity isn't very flash. The 45Hz point is probably -10dB, ie goneburger.
     
  5. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    If 96dB/1W/1M is the average efficiency, that's in the ballpark. As far as the low end goes, that can be (typically) either a -10dB or -3dB number, those are the two standards that are most commonly used. Both numbers would give you an idea how fast the rolloff occurs. If it's a -3dB number, I think that's pretty darn good. If it's the -10dB number, it's (maybe) a bit less than average but not all that bad either.

    Using 2 cabinets together will improve the low end extension, and increase the <200Hz efficiency as well. All in all it may be worth giving them a listen.
     
  6. the specs I gave was for 1 cab, I want to run a pair of them off of my head... I've got a kustom deep end 300w... the cabs are 412's..
     
  7. craig.p

    craig.p

    Sep 28, 2008
    New Hampshire
    X Hz to Y Hz is meaningless absent the -3dB and -10dB rolloff points. Whenever they're not provided, I always assume X and Y are -10dB points or worse. If you can't get the true response specs from the manufacturer, you can probably assume 45 Hz is at least 10 dB down because those are the games the SpecMeisters from Marketing play these days. And so, assume flat to 70-80, -3 dB at 60. Set your high-pass filter to 70 or 80 to avoid/delay overexcursion. If no high-pass filter, be extremely careful with bass boost and volume, watch for cone hop, etc. etc. etc.
     
  8. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    What kind of 412 is it?
     
  9. well... I'm actually looking at the seismic 412 cabs.. I'm thinking of ordering the stack since its only 400 bucks for the pair.. not out much if I don't care for em... I can resell them for almost that. I know they're mdf but I'm gentle with my stuff so no biggie. They're really guitar cabs, but I can't see them being too much worse than the 412 I'm running now which is loaded with 8ohm 50w radio shack speakers (to my dismay, since I thought it was all original... its an old GK cab I bought used)
     
  10. +1

    There are only so many 412's out there designed for bass.
     
  11. answered a minute ahead.

    Guitar 4x12 typically don't have very good lows for bass.
     
  12. craig.p

    craig.p

    Sep 28, 2008
    New Hampshire
    Wouldn't it make more sense to load the GK cab with proper drivers than buy a couple of cabs that won't sound anywhere near as good and will be worth almost nothing at resale time -- if you can unload them at all?
     
  13. No. It won't save any money, and loading a guitar cab with bass drivers has no guarantee to sound good.

    He should buy one decent used bass cab.
     
  14. I'm still not convinced my gk cab is a guitar cabinet... the design just doesn't make sense for a guitar cab... its 810 sized and crossfiring...
     
  15. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    I'm going to suggest that with this information, you would be a lot happier in the long run buying cabinets designed for bass.

    One of the problems with guitar drivers is that many (if not most) guitar speakers are designed with very little voice coil overhang, meaning that they do not have much linear excursion (and little to no Xmax). This means that you will experience a rapid rise in unpleasant distortion as soon as you start driving it even a little bit hard. It also turns out that Xmech (the limit before damage occurs) is also very small on most of these drivers, and if the cabinet is open back or semi-open there will be little mechanical control of the drivers thus all of the above really comes into play.

    Also, beware of MDF, it absorbs moisture and the expansion/contraction of the material can make the joints and vinyl seams really unstable.

    With all the good used gear on the market, if you don't mind heavy, there are plenty of great deals to be had.
     
  16. craig.p

    craig.p

    Sep 28, 2008
    New Hampshire
    Nowhere did DD say his GK cab is a guitar cab. At least I can't find it.
     
  17. He has old GK cab with radio shack drivers, looking to upgrade. The 4x12 guitar cabs are not the way to do it.
     
  18. It was speculation from a previous thread. I dont believe the OP really knows much about his current cab.
     
  19. craig.p

    craig.p

    Sep 28, 2008
    New Hampshire
    Then we need pics from DD!

    Pics, man! Pics!

    :D
     
  20. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    well... I'm actually looking at the seismic 412 cabs... They're really guitar cabs, but I can't see them being too much worse than the 412 I'm running now which is loaded with 8ohm 50w radio shack speakers
     

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