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Crossover on my 18

Discussion in 'Amps and Cabs [BG]' started by Tualatin, Mar 18, 2006.


  1. Tualatin

    Tualatin

    Feb 7, 2005
    Atlanta
    I'm running an external power amp slaved out of my 400+, to my 18 sub (400+ into 6x10). I'm thinking of trying a crossover to dived the range up a bit. Since I'm playing in low A, I worry about my tens getting destroyed again. This is my theory: Keeping the 40hz eq relatively low to protect the tens, and a crossover in line to the poweramp so the 18 dosen't see anything over 100hz or so. There is more than enough power going to the 18, so even if the signal from the preamp is cut a bit there is still tons of headroom to work with.
    How does this sound, will an active crossover accomplish what I want it to do? Is it a bad idea to split the freq's in the cabs? Should I eat more bran to stay regular?
     
  2. The 0x

    The 0x

    Aug 24, 2003
    Timonium, MD
    I don't see any problem with this.
     
  3. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    It's a bad idea not to.
     
  4. I'd do it the other way around. I'd run the sub off the 400+ and the 6x10 off of the external power amp. That way you can use a crossover to protect the 6x10 cab from frequencies below 40HZ. Doing it the other way (running the 6x10 off the 400+ and turning down the bass) is only going to let you cut the low frequencies by about 12db total. Doing it my way will let you cut low frequencies to the 6x10 cab by 24db per octave which will give you much greater control.
     
  5. The 0x

    The 0x

    Aug 24, 2003
    Timonium, MD
    Maybe, but usually mids & highs sound better through a valve amp (especially when overdriven), while keeping the low lows clean.
     
  6. True enough, but simply turning down the tone knob on the 400+ is not going to cut the low frequencies to the 6x10 cab by much and keep in mind that when you turn down the tone knob to the 6x10 cab you're also rolling off the bass to the sub which sort of defeats it's purpose.
     
  7. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    I do agree with using the tube power section for the mids and highs. Tens aren't all that delicate, so rolling off EQ will likely be adequate for the job there. I wouldn't do so with a graphic, I'd use the bass shelving pot, if the pre has one, as that will cut from 150 Hz or so on down. But the issue of getting enough signal into the 18 remains. If the send to its amp could be taken pre EQ that would do the trick. If not an additional outboard EQ could be used to boost the LF signal.
     
  8. Tualatin

    Tualatin

    Feb 7, 2005
    Atlanta
    Right, I was thinking about that. It would have to be trial and error I quess. I'm assuming that with the 40z eq turned down a bit, it will cut enough of the harmfull lows to the 6x10. As long as it still exists in the signal, the crossover will still pick it out and the amp can still power it.

    I'm also assuming that you can't run a powered signal (e.g. off the output tap on the 400+) into a crossover then into the cab, right?
     
  9. Right, unless you want to turn your crossover into a very effecient, buy short-lived smoke generator. You'd need to run the crossover between the slave-out on the 400+ and the input of the poweramp.