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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. MVE

    MVE

    Aug 8, 2010
    In response to the OPs question:

    1 SVT into 1 810= Loud Enough

    ;)
     
  2. mrjim123

    mrjim123 Supporting Member

    May 17, 2008
    Indy
    +1.
     
  3. higain617

    higain617

    Sep 12, 2013
    WA
    600 watts RMS is objectively louder than 300 watts RMS.
     
  4. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    To simplify this, which specifically addresses the concept that most solid state heads ~double their output power when the load is halved rather than with a tube amp which maintains constant power regardless of load (via the output matching transformer).

    1. For a doubling of output power (no matter how it's accomplished), there will be a theoretical gain of ~3dB SPL

    2. For a doubling of identical speakers, at the same total input power, there will be a theoretical increase in SPL of ~3dB. There will be more effective gain in the lower frequencies which serves to extend the low frequency response (for several reasons).

    3. For a doubling of power and speakers, there will be a theoretical increase in SPL of ~6dB as well as a slight extension of lower bass.

    Remember, we are talking about dB expressed as power, not voltage.
     
    HolmeBass and packhowitzer like this.
  5. Double E

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

    Dec 24, 2005
    Cleveland, OH
    A mere 3dB according to the experts.
     
  6. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Which isn't so mere when discussing a logarithmic value...
     
    MarkA and HolmeBass like this.
  7. MobileHolmes

    MobileHolmes I used to be BassoP

    Nov 4, 2006
    Iowa
    2 amps running 2 cabs is probably going to be louder, although how much louder is tricky (Not twice as loud for example).

    1. Volume is logarithmic, so doubling the power doesn't double the volume
    2. There are potentially impedence issues. Guitar amps (more often than not) will have taps so that the run the same wattage into different loads. Bass amps (more often than not), don't have taps, so they run different wattages into different loads (I don't know about SVT IIs specifically). but for example, my 500 watt Head is 500 into 4 ohms, but only 350 or so into 8. So, if you hooked up 2 8 ohm cabs, you'd have 500 watts from one head, but you'd only have 700 watts total from two heads each running an 8 ohm load
    3. 810s are really loud on their own anyway. 2 of them is probably dangerous
     
  8. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    See post #44, I addressed all of these scenarios.

    The SVT-II uses a tube output stage and has output transformer taps for both 2 and 4 ohms, so the power will remain constant. In this case, 2 amps with 2 cabinets will be ~6dB louder than 1 cabinets with 1 amp, and 3dB louder than 2 cabinets with 1 amp.
     
    Lobster11 likes this.
  9. MobileHolmes

    MobileHolmes I used to be BassoP

    Nov 4, 2006
    Iowa
    My bad.
     
  10. MobileHolmes

    MobileHolmes I used to be BassoP

    Nov 4, 2006
    Iowa

    While you're here, I've always wondered, is it only tube amps with different taps? Is this why this is a standard guitar amp feature and a weird bass one?
     
    HolmeBass likes this.
  11. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Yes, in general (there are a couple of obscure exceptions in each camp however), tube amps require matching transformers to match the higher plate impedance to the lower voice coil impedance.
     
    MobileHolmes and packhowitzer like this.
  12. higain617

    higain617

    Sep 12, 2013
    WA
    I’m not saying there’s a point to running two SVT heads for most applications.
     
  13. nilorius

    nilorius

    Oct 27, 2016
    Riga - Latvia
    Think that better is one amp for two cabs.
     
  14. DrewinHouston

    DrewinHouston Not currently practicing Supporting Member

    Apr 20, 2009
    Houston Heights, Texas
    Disclosure: I am not a great bass player
    I think everyone is begging the question, which was: which is louder, 1 amp with 2 cabinets or 2 amps with 2 cabinets.
     
  15. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    It depends on the amp.

    With a solid state amp (like anything in the Subway series), the SPL will almost exactly the same. The Subway doubles it's rated power when halving the load impedance. Doubling speakers in parallel halves the load impedance.

    With a tube amp (like the SVT-II), the SPL will be ~3dB higher with 2 amps than with 1 amp due to the doubling of power with 2 amps compared with 1 amp. The only way to double the power with the SVT-II is to double the number of amps.
     
    DrewinHouston and Lobster11 like this.
  16. Amajew

    Amajew Supporting Member

    Jan 11, 2016
    Here's one scenario that I experience

    D800 head.
    2 barefaced four 10's

    One cab pushing 400w. Loud as f

    Two cabs pushing 400 a piece

    You are louder than two 412 wielding guitarists and a heavy handed drummer with plenty of room to spare.
     
    agedhorse likes this.
  17. It depends on whether you are trying to rattle the door man's nuts or not. That 3dB extra might might all the difference. Probably not.

    It will LOOK heaps louder just sitting there.

    Don't forget your earplugs and industrial muffs.
     
  18. Thundar

    Thundar Living in sin at the Holiday Inn

    Now THAT is a great name for a band!
     
    DrMole and lowplaces like this.
  19. You have to be careful with the units of measurement and what you are doubling. Loudness is in dB, it's all relative, and pretty much a happy fudge. Twice as loud is by definition +10dB.

    Tl,Dr: yes.
     
  20. The other end of the scale is where the big action happens.
    1W
    2w
    4W someone tell that guitar player to keep a lid on it.
    8w
    16W
    32w oh there's a bass player.
    64W that's better. But tell that guitar player to shut the hell up.
    124w now we're talking
    248w who's ya Daddy? Crikey, who gave Keifer one of those?
     
    ctmullins, Ryan L. and agedhorse like this.

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