OK, so I don't get some thing...

Discussion in 'Amps and Cabs [BG]' started by Obsolex, Jul 7, 2003.

  1. Obsolex

    Obsolex Guest

    Nov 17, 2002
    Ok, i've read this many times, and just read it a minute or two ago. People say that you need at least 3-4 times the power of the guitar amp!!
    I mean, I remember when I was jamming with my "friends", and the guitarist had a Marshal half stack at 120 watts, and the drummer has a LOUD set. He used about 100 watts, and I used about 120-130 on an SWR Workingmans 15 combo amp.
    I just want to WHY you say to have 3-4 times the power... Headroom?
  2. wulf


    Apr 11, 2002
    Oxford, UK
    Headroom, so you can get a clean sound even at the peaks. If you want a distorted sound, a smaller amp turned up full might be what you're after... although you may end up sending it to an early grave!

    Also, low frequencies take more power to produce at a comparable volume.

  3. You lucky b*sta*d!!! You get by with 120 watts against a guitar stack???

    Seriously, I don't think the guitarist was using more than 10 watts if you could compete with your combo. BTW How do you know he was using 100 watts and you 120-130? There's no amp that tells you how many of its power it's using, unless you have a calibrated power level meter.

    I used to play in a band with 2 guitarists. One used a Koch powertone 120 watts head and 4x10 cab, and the other a full marshall stack with a 2x100 watts all tube power amp. The poor little bass amp was a Hartke 400 watt amp and a 4x10. NO way it could keep up. I had to EQ for an Eden midbass hump. My own stuff (1x15 and 2x10 on a 2x240 watts amp) was..... well.. able. Set flat.

    Ok end of rant ;)
  4. alexclaber

    alexclaber Commercial User

    Jun 19, 2001
    Brighton, UK
    Director - Barefaced Ltd
    Efficiency. A 4x12" guitar cab loaded with JBL E120 speakers has a sensitivity of 109db@1W1m. An Eden 410XLT (one of the most efficient bass cabs on the market) has a sensitivity of 106db@1W1m. Regardless of the fact that most bassists will boost the low bass to make up for the low-end roll-off of this cab, you'll still need twice as much power to be at the same volume as the guitar.

    Furthermore, due to human hearing being much more sensitive to midrange frequencies, even once you've got your bass to the same volume as the guitar (i.e. registering the same dB level) it won't sound as loud because the guitar is more midrangey.

    Note that most guitar speakers are of similarly high efficiency like the JBL E120 whilst most modern bass cabs are much less efficient than the 410XLT because they are smaller and have flatter frequency response. Consequently, the rule of thumb is changing from 2 times the power of the guitar to more like 10 times.

  5. mikemulcahy


    Jun 13, 2000
    The Abyss
    Read my profile, I aint scared of no guitar player.

    Bad grammar on purpose.

  6. :eek:

    No...you are not!:eek:

    Nice rig man...:)
  7. ZuluFunk

    ZuluFunk Supporting Member

    Apr 14, 2001
    Daredevil, the bassist with no fear!!!

    Me too. I haven't had any concerns once I went to a pre/p.a. rig. When I really need it, I add an extra 8ohm 112.
  8. Obsolex

    Obsolex Guest

    Nov 17, 2002
    I know the guitar was at 100 watts because his head puts out 100 watts, and it was on full. And i'm at an estimate of 120-130 because it was not on full, and was a little more than half way...
  9. Petebass


    Dec 22, 2002
    QLD Australia
    No offense man, but I don't believe you.......
  10. notduane


    Nov 24, 2000
    let's toss in this purty graph :)


    ( Fletcher-Munson curve )
  11. Lockout


    Dec 24, 2002
    Ok, could you explain to an idiot (me ;)) what exactly that chart means?

    Is it showing that as the frequency decreases, a higher intensity is needed to make the volume seem the same to our ears?
  12. notduane


    Nov 24, 2000
    pretty dang good for an "idiot" :)

    you're right on the money :D

    IOW, the ears response is NOT linear
  13. Lockout


    Dec 24, 2002
  14. steve-o

    steve-o Guest

    Apr 17, 2002
    do you know the commando heads by trace elliot?
    100 watts at 8 ohms..well i had that and an old crate sealed 410 cab..and i was able to keep up with anything around...including a double recti and mesa 412 cab...turned up...and a very loud drummer...

    i was very impressed...and it was only $99 new!! i was very suprised with the tone and everything..i love trace..

  15. snailplow

    snailplow Leon Phelps Wanna Be

    This particular post is perpetuating a common myth in how amps work.
    Most seem to think that the master volume gauges an amp's actual power output(i.e.: a 1000 watt amp with it's master knob turned half way up is producing 500 watts to the speaker(s)).
    This is not true.An amp produces it's maximum power at all times.The master volume control simply gauges how much of the signal is getting sent through the amp's power section.
  16. i think i am lucky.... our guitarist needs to turn up!! we use a 40watt combo for practice and church and i can get by with 75watt peavy......and i am told to turn down. but then again if we turn the guitar amp up to 4 we get ear bleeding levels in a basement..... but i guess im happy i dont get the guitarist who keeps turning up
  17. ZuluFunk

    ZuluFunk Supporting Member

    Apr 14, 2001
    More than lucky...blessed perhaps!
  18. well i dunno about when he comes back from flordia. he does high volume jamming 8-10 hours a day :eek: so im hoping he isn't deaf when he comes back so i wont have an out of controll guitarist.
  19. Petebass


    Dec 22, 2002
    QLD Australia
    Actually I must say I'm pretty lucky nowdays. None of the guitarists I play with are no where near as loud as those I've worked with in the past. It seems that buying a set of ear plugs set a message. Everyones seems to play softer now, thank God!
  20. snailplow

    snailplow Leon Phelps Wanna Be

    When my guitarist and I saw Tool live,they proved my arguement to him that you don't have to play as loud as Kiss does to come across as "Big" sounding(for lack of a better word).We walked out of the venue without our ears ringing.
    If I could have it my way,I'd find a drummer who uses the new version of Roland's V-drums so he/she could also turn down,while hitting as hard as he/she wants.
    My guitarist uses all solid state gear,so he gets all the gain he wants without being loud.Lower volumes at rehearsals help greatly when you're trying to make sure the band's vocal harmonies are right.