1. Please take 30 seconds to register your free account to remove most ads, post topics, make friends, earn reward points at our store, and more!  

whats the formula for Bass to guitar power?

Discussion in 'Basses [BG]' started by jerryjg, Dec 17, 2006.


  1. jerryjg

    jerryjg

    Aug 20, 2006
    Say the guitar players got a Marshall 100 watt full stack(2 four X twelve cabinets). How much bass power and speaker output do i need to keep up at full volume? I mean both amp and speakers? Could i simply halve that Bass requirement for a half stack Marshall with a 100 watt head?
     
  2. Ten Four One

    Ten Four One

    Dec 5, 2006
    4 times. :)

    Birds are small and their voices carry. But it takes an elephant to make a bass note that will travel for miles over the plains.
     
  3. Ten Four One

    Ten Four One

    Dec 5, 2006
    You could probably get away with a 300-400 watt head with a 4x10 cab as long as your guitarist wasn't really cranking away, which he hopefully isn't unless he's playing with John Bonham.
     
  4. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    I'm in the ten times crowd, unless your guitar player has a sincere desire to sit in the mix, which he doesn't.
     
  5. Lucky Flameout

    Lucky Flameout Dark Stage Krawler

    Nov 20, 2005
    Falcon, Colorado
    My guitar player runs a Laney stack (a 100 watt head unit and two 4X12 cabinets).

    I had a matching Laney bass amp, and could not keep up with him, even in small clubs.
    My rig was a Laney Richter R4H, a 300 (some paperwork said 350) watt head unit, one 4X10 cab and one 1X15 cab.
    I was ALWAYS pushing that rig.

    I switched to a Carvin RL1018 rig, Red Line 1,000 watt head unit, one 4X10 cab and one 1X18 cab.
    I have no trouble now, plus I don't have to push the rig hard.

    Bottom line, 3 TO 1 wasn't enough.......;)
     
  6. Ten Four One

    Ten Four One

    Dec 5, 2006
    120 vs 300 isn't 3 to 1, it's more like 2.5 to 1. A 2nd cab is always a good idea, provided you've got room in your car for it.

    And those 18's are monsters. I had one for a while (an old music man cab), while it was relatively light, it was as large as a house.
     
  7. Lucky Flameout

    Lucky Flameout Dark Stage Krawler

    Nov 20, 2005
    Falcon, Colorado
    My motto should be: "It helps to have a truck, and a roadie.......".;)
     
  8. A9X

    A9X

    Dec 27, 2003
    Australia
    Yes, theoretically with everything else being equal, to go an octave lower requires 4x the power. However the ear's sensitivity is lower at lower frequencies requiring even more level to compensate for apparent (lack of) loudness. Speakers are almost always less efficient at lower frequencies too.
     
  9. Ten Four One

    Ten Four One

    Dec 5, 2006
    "However the ear's sensitivity is lower at lower frequencies requiring even more level to compensate for apparent (lack of) loudness."

    That's only below 80db or so.... ;-) If I remember correctly, that's when the fletcher munsen curve approaches flat.

    Yeah, it takes more power to move a speaker enough to generate a 15 foot sound wave.

    Another way to think of it is "how big is an acoustic guitar? a voilin? how big is an upright bass?" You could almost draw a pyramid around them and nail the size vs. tonal characteristics.
     
  10. Ten Four One

    Ten Four One

    Dec 5, 2006
    Anyway... I was always pretty good with a Hartke 4000 a 4x10 and a 1x15, and while my band was considered loud, we were hardly going to 11.
     
  11. A9X

    A9X

    Dec 27, 2003
    Australia
    http://www.silcom.com/~aludwig/images/Fletcher-Munson.jpg
     
  12. Ten Four One

    Ten Four One

    Dec 5, 2006
    GAH! I Don't know what I clicked but I lost my post.

    Anyway, to sum up.

    If you look at the line between 100Hz and 300Hz - let's call this 200Hz, at 50dB ("Quiet restaurant inside") we have equal sensitivity to it and 1000Hz.

    By 90dB ("Loud factory, heavy truck at 1 m (3 ft), kitchen blender") or 100dB ("inside discothèque") it's around 150Hz.

    So we're reasonably flat at reasonable volumes.

    If you're chasing the ~3 octaves between 20Hz and 150Hz, the subwoofer range, and at "inside discothèque" volumes, then you'll probably need a monster rig.
     
  13. A9X

    A9X

    Dec 27, 2003
    Australia
    Below 100Hz and above 90dB or so, I'm still seeing several dB required to maintain apparent flat response in the bottom octave.
     
  14. Ten Four One

    Ten Four One

    Dec 5, 2006
    Besides, this statement "However the ear's sensitivity is lower at lower frequencies requiring even more level to compensate for apparent (lack of) loudness." is somewhat misleading.

    At every volume we hear the appropriate amount of bass for that volume. Every speaker manufacturer in the world touts how "flat" their speakers are. They don't tout how they compensate for the fletcher munsen curve by artificially boosting bass, unless their consumer base is the lowest of the low (I'm talking Bose customers here).

    If you played louder than the rest of the band in attempt to compensate for the way we hear, you're going to sound too loud. The brain knows this characteristic of the ear, and trying to trick the brain this way is just foolish.
     
  15. Ten Four One

    Ten Four One

    Dec 5, 2006
    especially at louder volumes.

    Modern music is artificially hyped this way - the frowny face EQ that gets applied in mastering to make it seem louder & more exciting at lower volumes to make it more competitive on the radio, but at concert level attempting to trick the ear this way is just silly.
     
  16. Bass_Machine

    Bass_Machine

    Oct 29, 2004
    UK
    Bass > Guitar
     
  17. A9X

    A9X

    Dec 27, 2003
    Australia
    I'm basing my comments on my ability to measure and interpret results as well as experience. The FM curves are pretty good.
     
  18. Ten Four One

    Ten Four One

    Dec 5, 2006
    *shrug* I wouldn't fight a guy who told me to get a 1000 watt amp and a couple of 8x10's. Just as long as he was willing to carry them for me.
     
  19. A9X

    A9X

    Dec 27, 2003
    Australia
    No 8x10 I've ever seen has any decent LF response.
     
  20. If you can't hear yourself through his volume then he needs to turn down.

    If you can't hear yourself over non mic'd drums then you need a bigger amp. I'm assuming you have a big enough amp to quite easily keep up with drums though.

    Your amps only need to be set loud enough so you can hear what you are playing. Leave it to the PA and techy to sort out how loud it is to the audience.

    Part of being a good band member is understanding how loud you need to be. In an ideal sound check, everyone should be able to hear each other and no one should be so loud that you can't hear yourself or someone else.
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.