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2 amps 2 cabs 1 amp 2 cabs

Discussion in 'Amps and Cabs [BG]' started by matzingerz, Sep 11, 2019.


  1. matzingerz

    matzingerz

    Dec 26, 2018
    Germany
    Hey People!
    Got a real newb question again. but is there a difference in precieved loudness or loudness in general if i hook up two of the same, lets say svt 2 pro amps, on two lets say svt 810 cabs (So 2 amps and 2 cabs) in comparison to one svt 2 pro on two svt 810.

    Thanks for your answers in advance
    Peace
     
  2. Warpeg

    Warpeg Supporting Member

    Jun 20, 2005
    Ohio
    Yes.
     
  3. Double E

    Double E I ain't got no time to play... Supporting Member

    Dec 24, 2005
    Cleveland, OH
    810 cabs are loud... the limiting factor is usually the power, so having twice the power will indeed yield more loudness. The same might not hold true for every other 2 amp 2 cab combination though.
     
    zon6c-f and lizardking837 like this.
  4. lizardking837

    lizardking837

    Jan 28, 2009
    Carrots
     
    TolerancEJ and alanolynn like this.
  5. ctmullins

    ctmullins fueled by beer and coconut Gold Supporting Member

    Apr 18, 2008
    MS Gulf Coast
    I'm highly opinionated and extremely self-assured
    Loudness is measured in deciBels, and is generated by speaker cones vibrating in boxes.

    Depending on how many cones are vibrating, how much they displace, and the characteristics of the box(es) they’re in, the set of drivers will be capable of a theoretical maximum amount of dB output.

    Getting the drivers to that point will require a certain amount of electrical energy, usually expressed in watts. The more efficient the driver(s), the fewer watts are needed to reach the same dB loudness.

    Delivering those watts is the job of the amplifier(s). If a single amplifier isn’t capable of delivering those watts, then splitting the job between two amps (each driving its own cab(s) ) will increase the dB output. But if a single amplifier is up to the task, then adding another amp buys you nothing (except the increased likelihood of damaging drivers).
     
    Honkey tonk, Charlzm and zon6c-f like this.
  6. sowilson

    sowilson

    Jul 5, 2013
    or if you love tube goodness how about four SVT CL (or VR) heads into two 8x10 cabs
     
    zon6c-f likes this.
  7. Double E

    Double E I ain't got no time to play... Supporting Member

    Dec 24, 2005
    Cleveland, OH
    A modern Ampeg SVT 810 is 800 watts... the SVT2PRO head is 300 watts... in the OP's scenario it's practically ideal to run both amps if the goal is to be as loud as possible.
     
    Erik Asma likes this.
  8. buldog5151bass

    buldog5151bass Kibble, milkbones, and P Basses. And redheads.

    Oct 22, 2003
    Connecticut
    As a general rule, more speaker area will increase volume more than more watts.
     
    Scottkarch and ctmullins like this.
  9. Coolhandjjl

    Coolhandjjl Supporting Member

    Oct 13, 2010
    Appleton
    Is anyone currently running such a rig? Gotta ask.......why?
    Adding the second head adds a theoretical 3dB, just a barely noticeable increase in perceived volume over the one head powering both cabs.

    And using even a 2nd 810 begs the same question. Unless you are playing huge ballrooms w/o PA support, why?
     
    Gearhead17 likes this.
  10. ctmullins

    ctmullins fueled by beer and coconut Gold Supporting Member

    Apr 18, 2008
    MS Gulf Coast
    I'm highly opinionated and extremely self-assured
    If only it were that simple.

    Wattage ratings on cabs are very nearly meaningless, as they don’t tell you about frequency response, they don’t tell you about efficiency (how many watts are actually producing sound versus how many watts are wasted as heat), and they don’t specify any sort of acceptable distortion level.

    And that’s just off the top of my head.

    If the concern is loudness, then the unit of analysis is deciBels, not watts.
     
    Frank77 likes this.
  11. Double E

    Double E I ain't got no time to play... Supporting Member

    Dec 24, 2005
    Cleveland, OH
    This is true, but this doesn't change the answer to the OP's question. doubling the power into two very power hungry cabs will definitely provide more useful headroom volume-wise than half the power into the same two cabs.
     
    smogg likes this.
  12. el murdoque

    el murdoque

    Mar 10, 2013
    Germany
    The SVT2 Pro, being a tube amp, will deliver 300 Watts regardless of the attached load.
    So in the scenario with one head and two cabs, the 300 Watts will be shared between the two cabinets while in the scenario with two heads each cab receives the full 300 Watts.

    So the scenario with two heads will be 3dB louder.

    Replace that amp with a SS head and the load difference will more or less balance that issue.
     
    Sparkl, basscooker and ctmullins like this.
  13. buldog5151bass

    buldog5151bass Kibble, milkbones, and P Basses. And redheads.

    Oct 22, 2003
    Connecticut
    Unless the power overwhelms the cab.
     
  14. Double E

    Double E I ain't got no time to play... Supporting Member

    Dec 24, 2005
    Cleveland, OH
    True again... but not a problem with the gear that the OP is referencing...
     
    smogg likes this.
  15. Coolhandjjl

    Coolhandjjl Supporting Member

    Oct 13, 2010
    Appleton
    I would help to know what the OPs goals are.

    If he wants a rig twice as loud, it's not as simple as adding a second head. You need to add 10dB to get twice as much perceived volume. Many ways to do that. I'll illustrate one way below:
    (Since we're talking tube heads, no need to worry about running at 4 ohms putting out more power than running at 8 ohms that SS heads do.)

    Base rig- SVT + 'Fridge. You're a rock god of bassdom

    SVT + 2 'Fridges = +3dB. An SVT will adequately power two 'Fridges.

    SVT + 2 'Fridges plus another SVT + 2 'Fridges = +6dB. That's a ton of gear and we haven't yet doubled the amount of perceived volume yet.

    Should we go on?
     
    Honkey tonk, five7, Dabndug and 5 others like this.
  16. Double E

    Double E I ain't got no time to play... Supporting Member

    Dec 24, 2005
    Cleveland, OH
    No, I don't think so... if the same power source, tubes or not, is connected to multiple drivers the wattage will be divided amongst them. If what you propose is true then how is it that each driver isn't getting it's own 300 watts?
     
  17. Four amps into two cabinets is a recipe for letting the magic smoke out! :(
     
    Bahjark likes this.
  18. Coolhandjjl

    Coolhandjjl Supporting Member

    Oct 13, 2010
    Appleton
    Doubling the amount of drivers (even with the amp putting out the exact same amount of power as before) yields a theoretical increase of 3dB. Simple physics at work here.

    We always use dBs when addressing loudness or perceived volume.
     
    Last edited: Sep 11, 2019
  19. Coolhandjjl

    Coolhandjjl Supporting Member

    Oct 13, 2010
    Appleton
    ‘Fridges can be split via a connection on the rear so one amp can drive the top four drivers and another amp can drive the bottom four drivers.

    And the SVT can drive 2ohm loads.

    So you could have 4 SVTs and 2 ‘Fridges for an increase of 6dB over our base rig of 1 SVT with 1 ‘Fridge.
     
    sowilson likes this.
  20. Double E

    Double E I ain't got no time to play... Supporting Member

    Dec 24, 2005
    Cleveland, OH
    The modern SVT 8x10 cab is basically two 400 watt 4x10's... no problem at all feeding each 8x10 with two 300 watt SVT2PRO amps.

    I am pretty sure that doubling power is what calculates to the rule-of-thumb 3db increase. Doubling the amount of drivers should make a much more substantial difference.
     
    mrjim123 likes this.

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