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Am I crazy or is something wrong...

Discussion in 'Amps and Cabs [BG]' started by ardorx, Aug 28, 2005.

  1. ardorx


    Sep 23, 2004
    Sugar Land, TX
    I have an Ampeg 410HEN cab and i'm powering it with a QSC RMX 1450 with a Sansamp RBI. Lastnight i had a gig and I had to turn the power amp and the pre almost all the way up to hear myself over everything. Is that normal or might something be wrong? Please let me know. thanks.
  2. ardorx


    Sep 23, 2004
    Sugar Land, TX
  3. 8mmOD


    Mar 20, 2005
    I endorse & use Tech 21 pedals, Eminence loaded cabs, EMG pickups, Jim Dunlop picks & Ernie Ball Strings, BC Rich Basses.
    i probably won't have an answer for you, but is that the first time you ever used that setup or did it work before last night?
  4. seanm

    seanm I'd kill for a Nobel Peace Prize! Supporting Member

    Feb 19, 2004
    Ottawa, Canada
    Did you bridge the power amp into the Ampeg? Is the cab 4 or 8 ohms?
  5. ardorx


    Sep 23, 2004
    Sugar Land, TX
    No, I didn't bridge it, and it's 8 ohms.
  6. JayAmel

    JayAmel Moderator Staff Member Supporting Member

    Mar 3, 2002
    Carcassonne, France
    Well, if you didn't bridge the power amp, then the power sent to this 8 ohm cab is 280 W at a maximum, according to QSC RMX-1450 specs .

    Even worse, if you have to crank it up all the way, you may cause severe damage to the speakers by generating some kind of "buzzing" distorsion.

    I'd suggest that you bridge the amp. You will then be able to send 900 W to your cab. Though, IMO you should care to adjust power amp level halfway, which should be more than enough in most cases, unless your guitarist plays through a wall of Triple Rectifiers...

    Hope this helps,
  7. popinfresh


    Dec 23, 2004
    Melbourne, Aus
    What EQ do you use on stage?

    Also, was it a first gig, or bigger than usual? No offence to the 'Peg fans out there.. But I ALWAYS get lost in the mix when using ampeg cabs.
  8. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    You can power it with a million watts and it won't matter. Check out the thread on power compression. Anything over 1/2 of the cabinet's rating just gets burned off as heat. Being a 4x10 and assuming you have it on the floor the likely problem is that the midrange frequencies critical to your being able to hear what you are playing, which are extremely directional in a 4x10, aren't reaching your ears. Tilt the cabinet back.
  9. KJung

    KJung Supporting Member

    +1 on the bridging into 8ohms... and also check to make sure you do not have too 'scooped' of an EQ curve on your preamp.

    Tilting back a 410 to hear better? If you have the EQ set 'correctly', you should have no problem hearing the 410, and you probably need all the floor coupling you can get, since it sounds like you are playing at pretty high volumes.
  10. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    You don't lose coupling by tilting the cab. Even if you went so far as to lie it on its back it would still be radiating into half space as far as the bass frequencies are concerned. The problem lies in the midrange,and it has nothing to do with EQ. A 4x10 cab is a wavelength high from about 500 Hz, above which dispersion on the vertical plane gets very narrow. With the cab pointing straight if you stand too close you won't be able to hear the midrange because your ears aren't within the midrange beamwidth. The non-directional bass frequencies may be there, but the ear is less sensitive to bass frequencies than midrange by as much as a 10:1 ratio. If the loudest sources of midrange frequencies that he's hearing on stage are coming from instruments other than his own he'll hear them, not himself. Tilting the cab back a few degrees is the easiest way to prevent that.
  11. ardorx


    Sep 23, 2004
    Sugar Land, TX
    i appreciate this.
  12. In addition to what's already been mentioned, is it possible ear fatigue may be playing a role here? Does this happen all night long, or more toward the end of the night?
  13. KJung

    KJung Supporting Member

    Makes sense... I never had this problem with a 410, but maybe I'm too old and not playing loud enough anymore!!!! :cool:
  14. Fred312b

    Fred312b Proof that gear doesn't make you a better player Supporting Member

    Apr 23, 2002
    Chicago, IL
    I just think he's crazy :smug:
  15. 4Mal

    4Mal Supporting Member

    Jun 2, 2002
    Columbia River Gorge
    1. Yes you're crazy, but not for the reason you think...

    2. The RBI has a notoriously low output. The QSC might not be seeing enough signal to drive it to it's rated capacity.

    3. If the 4x10 is on the floor, and you're standing close in, the majority of the sound is blowing out past your knees. An amp stand would be a real help here. I run my 2x10 on a tilt back stand and have no complaints.
  16. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Or the guys you're playing with aren't so loud that they won't let you hear yourself.