Car Audio Bass Blocker DIY

Discussion in 'The Projects Forum' started by LED Man, Sep 14, 2009.

  1. LED Man

    Thread Starter Active Member

    Jan 15, 2008
    Hey Guys,

    I'm interested in building my own bass blockers for my car speakers instead of having to buy them. I figure since they are most likely simply high pass filters that I can just buy a small pcb, throw a resistor and capacitor and install it in line with the positive wire from each speaker. Obviously I would use separate filters for each speaker. Would this work? Thanks.
  2. LED Man

    Thread Starter Active Member

    Jan 15, 2008
    Anyone have any input on this? Thanks.
  3. Mu86neer


    May 1, 2009
    we would be grateful, if u just post a circuit diagram to drive the ideas ;)
  4. Audioguru


    Dec 20, 2007
    The Bass Blocker is just a capacitor in series with the speaker.
    Cheap two-way speakers use a single capacitor in series with the tweeter as a "crossover network".

    If you use a 267uF capacitor then a 4 ohm speaker will be down -3dB at 150Hz and down only -6dB at 75Hz which is not much of a reduction of level.
    A 267uF capacitor is not available but a 270uF one might be, but it will be electrolytic type that has a wide tolerance for its value. Then the cutoff frequency will not be accurate.
    Since the speaker resonates at about 75Hz then the capacitor is almost useless.

    The Bass Blocker is supposed to be for mid-range and tweeters but a 150Hz cutoff frequency is much too low.
  5. SgtWookie


    Jul 17, 2007
    Those electrolytic capacitors being used for the Bass Blockers are non-polarized electrolytics. If you used a single standard polarized electrolytic, it would rapidly get destroyed.

    However, you could use a couple of 560 electrolytics connected in series with their negative or positive leads connected together. Wouldn't be as good as a non-polarized electrolytic, but might be cheaper.

    Of course, the Bass Blockers are pretty inexpensive anyway.
  6. Steve C

    Active Member

    Nov 29, 2008
    sure does work.

    Dont need the resistor.

    plenty of internet applications to help pick capacitor value. Here is bing's first hit on crossover calculators

    Once you have a ballpark value you want, Fry's sells the parts for a few bucks, or you can buy them online. 50v suffices just fine.
  7. bountyhunter

    Well-Known Member

    Sep 7, 2009
    Some of the NPEs I have seen were two electrolytics in series with the cases back to back with the tube wrap around the whole thing with the leads out either end.