Crossover for 8 Ohm Cab OK for new 4 Ohm load?

Discussion in 'Amps [BG]' started by DrewFolkadelics, Oct 17, 2013.


  1. DrewFolkadelics

    DrewFolkadelics

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    Hello TB!

    I've searched and searched to find an answer to this question, but I can't seem to find a definitive answer.

    Basically I have an SVT210HE (originally 8 ohm) empty cabinet w/ original horn and L-Pad/Jack that I put 2 Eminence BP102's into (each 8 ohms). I'm going to wire parallel for a usable 4 ohm load, but I'm just wondering if I can just use the same crossover/horn or if I'm better off just disconnecting it altogether before potentially frying anything in there.

    Please excuse my ignorance and thanks in advance for any insight!
     
  2. B-string

    B-string Gold Supporting Member

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    The crossover is just for the horn which is still 8 ohms. Wire and go, the crossover won't care what the woofers are.
     
  3. NYCbassist

    NYCbassist Supporting Member

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    The Crossover should match the resistance of the drivers. Frequency response will be affected reducing the highs. It may still be usable but it's hit or miss unless you really study and apply the science behind it. If your Crossover has inductors controlling the Highs allowed into the Woofer than it will obviously affect more than just the tweeter.
     
  4. B-string

    B-string Gold Supporting Member

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    I really doubt there is any pass filter on the woofers. It is a mass produced standard production cab for Bass guitar use.
     
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  6. DrewFolkadelics

    DrewFolkadelics

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    Still confused (but very thankful for the advice). Inside it has a bulb and some intricate looking electronics.

    I just want to be sure that I won't hurt anything, even if it sounds bad. I am willing to give it a go just to test.
     
  7. B-string

    B-string Gold Supporting Member

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    The bulbs are protection for the crossover/tweeter horn. You won't hurt anything by trying.
     
  8. NYCbassist

    NYCbassist Supporting Member

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  9. DrewFolkadelics

    DrewFolkadelics

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    Thank you both for the advice! Will report back...
     
  10. NYCbassist

    NYCbassist Supporting Member

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    No sweat. I keep my horns turned off anyway.
     
  11. 1958Bassman

    1958Bassman

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    An electrical conductor's resistance will increase when its temperature increases and in the case of the bulb, it acts to reduce the current/voltage to the horn. If the voice coil has to do this on its own, you'll run into 'thermal compression', which is a term you may have seen. If you haven't seen it, you will. Heat kills everything, eventually, and voice coils are included. A bulb is a cheap, reliable device for keeping drivers from dying.
     
  12. Bassamatic

    Bassamatic keepin' the beat since the 60's

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    It really depends on whether it is a real crossover, or just a HF blocker to protect the horns.

    If it is a real 2-way crossover, the frequencies sent to the woofer will be off considerably as the caps and inductors are tuned for 8 Ohms impedance. You can't hurt anything, but it might not sound very good - it could be off by an octave in either direction. Try it and be sure that the total power is about the same as the cabinet was originally spec'd for - crossovers have limits to what they can handle.

    The light bulb acts as a current limiter that will lower the level sent to the horns when the current gets too high - loud peaks, etc.
     
  13. DrewFolkadelics

    DrewFolkadelics

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    So far sounds great and functions perfectly! Thanks for all the input everyone! I will reply back if anything explodes :)
     
  14. B-string

    B-string Gold Supporting Member

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