Watts vs Decibels is it worth it?

Discussion in 'Amps and Cabs [BG]' started by Moordoom, Nov 24, 2016.

  1. pudgychef likes this.
  2. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    With the two 8 ohm cabs, your amp will be capable of producing 220W.
  3. StayLow


    Mar 14, 2008
    There's a world-famous metal band I've seen live many times (won't say which), with an amazing, skilled, musically educated bassist (diploma), fingers flying, and in their live mix unless the guitars are at rest you can't even tell if he's plugged in unless he's waaaay up the neck. Massive rig too, and I mean can't tell as a bassist standing 20 ft. in front of said rig. Literally I'd look at his amp to see if the pilot light was on. Can't make out most of the guitar chops either.

    One day I'm chatting with their drummer, highly lauded, accomplished and musically educated (diploma) so you'd think this issue or concept wouldn't be news but I mention it to him anyway. Politely. "What's the culture like in your band, what with all those stacks and shredding ... do y'all discuss EQ'ing for the common good?" He responds that only recently on the bus they've been discussing how to EQ for a better live mix after being told by enough people that there are issues which won't be resolved by adding amps & cabs. After more than a decade on tour and half a dozen studio albums.

    Point being, we all can benefit from outside input and self-reflection sometimes, and studying how we actually sound live vs. how the same EQ works at home or in the jam room or in front of your speaker stack. Whether it be the acoustic guitarist singer/songwriter EQ'ing so that the low end doesn't rumble in the room, they keys player working with you to keep the low end uncluttered, or the guitarists ...or maybe even the bassist.
  4. AaronVonRock


    Feb 22, 2013
    Come on. Name the band.
  5. ubernator


    Oct 30, 2004
    lost angels
    I'm sure I will catch flack for this, but crate amps and carvin cabs have to be about the lowest of the barrel when it comes to efficiency, especially at lower frequencies.

    ShadowImage likes this.
  6. Gizmot


    Mar 22, 2009
    Nashville area
    There are quite a few online SPL calculators you can use if you want to get scientific. What those do is look at the sensitivity of your speaker(s), add how much power you have and give you a figure. If you want to go even further there are inverse square law calculators that will give you output level at distances (SPL drops by 6 dB everytime you double the distance).
  7. The Eliminator... It's all you really need...

    Last edited: Nov 24, 2016
  8. ShadowImage

    ShadowImage Guest

    Jan 12, 2016
    His amp only has 220 watts at 4ohms which is... not much! More speakers does not equal more sound if your amp is not powerful enough to drive them. Each of his cabs are only getting 110 watts. Assuming the cabs are rated at 400+ watts each he is barely driving them. The amp is the problem here.
    HolmeBass likes this.
  9. pudgychef

    pudgychef In Memoriam

    Jan 22, 2005
    Chongqing, China

    are your mids quite scooped? (smiley face eq)
  10. Robert Sperling

    Robert Sperling Crazybassman72

    Jan 26, 2016
    Long Island, NY
    My answer to full stack guitar amps... An Ampeg SVT7Pro pushing the 810 Classic (or sometimes an old 1976ish
    Fender VT15 modified with 2 Carvin PS15's, reinforced and ported) AND a Carvin B2000 pushing
    2 Carvin BXR10.4's ....3,000 watts and 16x10's (or 8x10's and 2x15's) is pretty hard to get lost in the mix, or
    for a guitar rig to drown out!
  11. GMC


    Jan 1, 2006
    Wiltshire, UK
    Looking at wattage alone (especially manufactures claims) to measure perceived loudness is a bit like looking at a chaps height to see how he'd be in a fight.
    Most 500w combos are lying quite blatantly, the head is usually measured at 4 Ohms...and the combo is 8 Ohms. You have to add a 2nd cab to get the full power...and that's assuming the manufacturer wasn't over estimating the power output of the power amp section.
  12. A Carvin B2000 on those two Carvin 410s should get ya heard.
    Getting the gui**** to turn down and not be in the PA should help a lot.
    A more mid forward EQ will put more of the power you have into a
    more efficient freq range.
    Cirk likes this.
  13. Robert Sperling

    Robert Sperling Crazybassman72

    Jan 26, 2016
    Long Island, NY
    To op: I had originally the Carvin BR410 4ohm and an SWR 350XPro, so the single 410 was getting about 350watts
    from the SWR but, as you've noticed it's not really that loud. When I wanted to replace heads for something more
    powerful and add a 2nd 410 I was kind of stuck because the 2nd cabinet needed to be 4ohms as well, creating
    a 2ohm load. Not many amplifiers out there capable of carrying a 2ohm load. I decided on a 2nd BR410-4
    and the Carvin B2000. Let me tell ya, that combo was kickin...plenty of headroom. I just switched to the
    BXR10.4's because I want volume AND as much clarity as possible. I'm very happy with my Carvin rig!
  14. brianrost

    brianrost Gold Supporting Member

    Apr 26, 2000
    Boston, Taxachusetts
    Slow down guys...if you don't change the cabinet used, increasing wattage does increase loudness in a logarithmic fashion. Double power, add 3dB, ten times the power, add 10dB (twice as loud to the human ear).

    To the EQ sugestion: if you are out of headroom already an EQ boost is going to make things worse by reducing headroom. Judicious EQ cuts however can increase headroom, like reducing the bottom octave.

    The response of the Carvin 4-10 is what most people would call "scooped", reduced response in parts of the mids to make the lows and highs stnd out more. While that can sound great with lots of power it can get you buried behind instruments with lots of mids, like electric guitars.

    To the OP: My rule of thumb has beenif I'm not loud enough, I need and amp with at least 4x the wattge...in your case something that can out out about 1000 watts. That is a lot of power...maybe your band is just too loud. Buy earplugs! ;)
  15. 40Hz

    40Hz Supporting Member

    Short answer - no.

    The human ear rapidly desensitizes as volume increases. So louder beyond a certain point becomes nothing but noise.

    Chasing watts or decibles is a waste of time, money and effort. You need to get a balanced FOH mix, as others have mentioned, in order to play loud music. Not a bigger louder amp.
    Cirk likes this.
  16. The answer is.... your lead guy needs a new amp ;)

    Seriously, 100W is way more guitar than is necessary for any venue I frequent... Most guitarists I play with use less than half that, typically even down in the 20-30 range.
  17. Allow me to make some slight adjustments...

    "...watts to decibels"
    When you speak of decibels in absolute terms you need to include what the db is referencing.
    That would be the the letter(s) following the db. Example... dbm the m means relative to one milliwatt. For dbw the w means relative to one watt. You only use db by itself when comparing two similar things. "Amplifier A is 10 db more than amplifier B."

    It also appears that when you used the cited calculator, you used the dbm numbers but called them dbw.
    If you go back and plug in the same numbers you get:

    200w = 23dbw
    500w = 27dbw
    1000w =30dbw

    We've all heard it here a thousand times, people stating that double the power is an increase of 3db.
    As you can see here going from 500 to 1000 watts is double the power or a 3 db increase.
    Likewise if you plug 100 watts into the calculator it verifies that 1000 watts is 10db higher than 100 watts.
    That may account for a couple of other folks who said your numbers were incorrect.
    agedhorse likes this.
  18. ficelles


    Feb 28, 2010
    Devon, England
    That's true, but dB unqualified is generally taken to mean sound pressure level in air (unweighted) referencing 0.02 mPa which is the limit of sensitivity of human hearing.

    Incidentally (for those that don't already know) the unit of measurement is actually the Bel scale, a logarithmic ratio scale named after Alexander Graham Bell, and the deci part comes from the need to divide the original unit by 10 to make the quantities more usable in modern science. Which is why the d is correctly lower case and the B is correctly upper case. I now pass on the hat of pedantry to someone else...
    HolmeBass likes this.
  19. hbarcat

    hbarcat Supporting Member

    Aug 24, 2006
    Rochelle, Illinois
    In my very experienced opinion as a performer and as a sound tech, your problems are not with your equipment but with how you are using it. You need to go back to basics.

    Start with your stage sound. No member of the band should be any louder than necessary to hear yourselves at a reasonable volume with each instrument at the same moderate level. The drummer shouldn't need to hit very hard. Each instrument should adjust their volume to be no louder than the drums.

    Your 220 watt head and twin 4x10's are more than enough for stage volume and you should be easily heard anywhere on stage. If your guitar player has a 100 watt head then he should have his volume set very low so as not to drown out the others. Set the vocal monitors appropriately to match everything else.

    If you have a SPL meter, you should read the drums at about 100dB @ 10 ft. Bring every other instrument in isolation, including vocals, to match the 100dB. The entire band playing together should be about 105db constant, with peaks no more than 110dB. This won't be loud enough to fill anything but the smallest coffee house, but that's not the goal here. Your stage volume is just for the band to hear clearly without being too loud.

    The PA is for filling the venue for your audience and it's really treated as a separate entity from your stage sound. DI your bass amp, and mic the guitar, vocals (obviously) and the kick and snare drum (if you want). Let the 1000 watts from your PA amp do the work.

    Not sure why you aren't currently running the bass through the PA. If you're afraid of blowing your PA speakers with low frequencies, then you should look to upgrade the PA's low frequency capability instead of wasting your time trying to use your bass amp and cab to carry the whole room.
    Kubicki Fan, Cirk and JohnMCA72 like this.
  20. All the math in this discussion is fun. But...

    A 220 watt solid state Crate to carry a 300 person room? Nope.
    ShadowImage likes this.
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