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350 watt Bass Blockers??

Discussion in 'Amps and Cabs [BG]' started by robd, Apr 23, 2004.

  1. Anyone know of a product kind of like the bass blockers you put in car stereo's (passive high pass filter) but that will handle higher wattage??

    What I want to do is....

    I'm playing thru a 350 watt amp into 2 cabs. 1, 1x15 and 1, 2x10. When I put enough bass into the signal to make the B string really boom thru the 15, it has too much low end for the 2x10's. I really don't want to go the bi-amp/crossover route, so I figured if I could find a passive bassblocker that I could put before the 2x10's to cut out everything below say 50-80k, that might work.

    I found some passive high pass filters at Partsexpress ( http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=266-154 ) but they said they would only handle 250 watts

    Anybody ever heard of such a thing?

    Would this work or is this a dumb idea??


  2. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Since you're running your 15 full range, the caibinets will share the amps power geting...say 175 Watts each.

    The only thing that I don't like about the crossover that you showed us is that the inductor has an iron core. Crossover builders use iron core inductors to save money on parts as less copper is required for the same inductance in an iron core inductor than in an air core unit.

    If you push the crossover hard enough to saturate the inductor's core, the signal hitting your 2x10 wll be distorted. An air core inductor would be a better choice.

    I believe that Parts Express includes a chart in their catalog to help you choose components whe building your own crossover.

    I believe that bass blockers are just a capacitor with a resistor (of some known value) across it (probably a high resistance relative to the system impedance).
  3. Ericman197


    Feb 23, 2004
    If you know a bit about electronics and wiring, you could wire several of such devices together. One alone might be good for 250 watts, but two in parallel could handle 500 watts.
  4. Where I probably know enough to wire 2 in parallel I looked at PE's crossover builders chart and went cross-eyed. I had no clue of what they were talking about except now that you mention it I do remember reading the part that said to use air core inductors.

    I would really prefer to buy one rather (or 2 and wire them together) and spend my time playing bass rather then learning how to design and build crossovers. Unless someone knows of a complete idiots guide (with pictures) to building one of these things.

    Any other suggestions?

    Also can anyone confirm that 2 of these in parallel would be good for 500 watts. (nothing personal Ericman) And wouldn't wiring 2 together change their impedance?? Would I have to wire 2 - 4 ohms together in parallel to equal a single 8 ohm filter??

    Any other suggestions welcome, thanks for those so far.
  5. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    I don't know that you'd double the power capability by connecting two in parallel, but you would cut the crossover freqency in half at a given impedance... You're doubling the capacitance (caps in parallel add) which would cut the crossover frequency by a factor of 2.

    This device is a 12db/octave high-pass filter. It consists of a cap in series between line and load and an inductor in parallel with the load.

    The power limitations on a cap come from its voltage rating (I believe). When you connect two of these filters in parallel, the caps are connected in parallel so each one sees the same voltage that it would when used singly. Since the voltage rating doesn't go up (as it would if the caps were connected in series (probably with a high resistance voltage divider network across them to make sure that each cap sees half voltage)) I'm not confident that the power rating of the crossover would increase.

    However, if the power rating was limited by the wire size of the inductor and not the voltage rating of the cap, then I could agree that the power rating would increase.

    As I originally wrote, each cabinet would see half the total power that the amp is putting out anyway and at 175 watts per cabinet (half of 350) its below the 250 watt rating of the crossover.

    This make sense to anyone?