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Headroom and pushing a cab too much?

Discussion in 'Amps and Cabs [BG]' started by uglycicles, Apr 26, 2004.


  1. uglycicles

    uglycicles Supporting Member

    Dec 10, 2003
    Southwest Chicago
    Sorry in advance for a possibly stupid question(s):

    I just picked up an Eden D-410XLT, and I'm powering it with an Ampeg SVT 4-PRO (mono bridged 1200 watts into 4 ohm 750 watt cab)

    My question is.....as far as turning up volume on the amp, where do stop before you start pushing the cabinet to a danger point? 12 o'clock? How do you know where your limit is?

    I played a gig this weekend and had it turned up to 10-11 o' clock - good sound, but I was scared to go any higher.

    Also, I have both passive preamp and active preamp basses - on the active with the -15dB pad engaged there was a pretty dramtic rolloff in sound (it was obviously working ;) ). What sort of problems am I opening up if I don't use the pad with the active?

    This is the first time I've had a rig with headroom, and I'm deathly afraid of ruining this nice cab.

    Thanks for your help. :)
     
  2. BruceWane

    BruceWane

    Oct 31, 2002
    Houston, TX
    Eh, perhaps you meant Ampeg SVT-4?

    Unless you're using a lot of compression, you're fine. Keep an ear out for clipping, and back off as soon as you hear any. You can safely run up to 2X your cabs rated power as long as you are careful to avoid clipping.
     
  3. uglycicles

    uglycicles Supporting Member

    Dec 10, 2003
    Southwest Chicago
    yes bruce, svt-4pro - sorry. thanks for the advice.
    any thoughts on the -15db pad?
     
  4. BruceWane

    BruceWane

    Oct 31, 2002
    Houston, TX
    You've got a clip light on the preamp section, don't you? As long as the bass isn't clipping the preamp, don't use the pad. Most active basses are not really any louder than passive basses if you use their eq correctly - i.e., as little as possible. I suppose there are some on-board active pre's that have a really hot output and thus would need a -15db pad, but all my active basses are fine without it.

    EQ on an active bass should be used in a manner that doesn't boost the overall signal. If your boosting lows by a quarter turn and boosting highs by an eighth, try leaving your lows flat and cutting highs by an eighth instead. The rule with ALL eq is - no gain, no pain. As long as you abide by this, you shouldn't need to pad the input
     
  5. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    Yep, the preamp clip light should flash sometimes, but not stay lit a lot. Then you are at a good level for least noise and least clipping.

    Master can then be turned to wherever floats your boat.

    Where the knob points has no particular meaning other than "higher is louder".

    The preamp lite warns you a bit before actual clipping, so you can push it some......
     
  6. uglycicles

    uglycicles Supporting Member

    Dec 10, 2003
    Southwest Chicago
    thanks to all - I appreciate it :)
     
  7. Mindabout

    Mindabout

    Apr 11, 2004
    Australia
    What is clipping? Is this what occurs when the headroom is all used up? Does it make an actual discernable sound?
     
  8. MattyN

    MattyN

    May 26, 2003
    Seattle, WA
    clipping is basically just distortion caused by overload.

    it sounds kind of like a radio signal that is breaking up because you're out of range... but way worse. you'll know it when you hear it.

    the term "clipping" refers to the truncation of an AC signal waveform.

    -M