4 speakers. standard amp. High pass filter "front", low pass filter "rear"?

Discussion in 'General Car Audio Discussions' started by mcfontio, Mar 13, 2012.

  1. mcfontio

    mcfontio New Member

    Howdy y'all. I'm coming over here from a live sound forum but need some ideas for a car audio setup I'm putting onto a pedal powered car.
    I have a standard 4 channel (2 front 2 rear) CD/aux in in-dash amp and 4 speakers. 2 of them have what looks like a HF driver built in and the other two are a pair of bose speakers. Because I want to spend as little on this project as possible I want to do this:

    1: Have the 2 speakers with the HF driver running on the "front" side of the amp with a passive high pass filter.

    and

    2: the 2 bose speakers running on the "back" channel with a low pass filter with an enclosure so I can take advantage of any coupling benefits from that. I'd like to see these speakers pushing nothing higher than say... 100hz.

    This whole thing is going to be powered by a single car battery on cruiser rides so I do not want to get any more amps involved. I also don't know the exact specs of this amp but imagine that it wont handle the impedance of just crossing over a single channel (say "front") into all four speakers. This could turn rather complicated if I want a smooth transition between the high and low frequencies because I believe the passive filters need to be built according to the speakers exact specs.

    I could just effen hook it up and forget about having the speakers crossed over, but if crossing over is key for a PA system, it's certainly desirable for car audio as well, even if I'm working with small speakers. Anyone know of any good sites with information that might be useful?

    Thanks
     
    Last edited: Mar 13, 2012
  2. mcfontio

    mcfontio New Member

    Oops... wrong forum section... And because I do not have permission to send messages, can a moderator move this??? :D
     
  3. Ranger SVO

    Ranger SVO Full Member

    OK Its been moved

    You didnt say what size the front speakers are. Anyway, if you want the sound to blend, I would recommend that you do not use a High Pass filter on the front speakers. If its a small speaker, 3-1/2 or 4-inch, then use a single capacitor. A 199uf or a 165uf non polar should block enough lower fequencies. The roll off would be shallow enough so the bass should sound like its coming from the front speakers.

    Again you told me nothing about the bose speakers. But it may not matter, without specs (thiele /small) enclosure design would be a guess. With your 100Hz frequency in mind, I would hope the woofer is atleast an 8-inch speaker.
     
  4. mcfontio

    mcfontio New Member

    Thanks for some help. And moving it.

    The front speakers are about 6" by 4". So with that cap, those speakers will sill be producing the lower frequencies? Hummm. I really just wanted to hobble together a 'crossover' somehow to ease the sound the speakers need to make. Now I'm thinking about just leaving the "front" speakers alone and using a low pass on the two bose speakers. And the bose speakers are 5" speakers. My little JBL near field monitors go to about 50hz and they're only 5". They're pretty damn impressive for a 5" speaker. I'm not looking for a ton of sound either. Just some added lower frequencies. Do you think those bose speakers have the lower frequencies attenuated out? I'd like them pushing nothing above 100hz. That should free up their ability to produce those sounds.... right? I know bose isn't exactly the best name in speakers... the "ooohh, aahhh" factor seems to be their focus.

    I'm going to collect some data from these speakers and the amp for my next post. There's no information on the actual speaker.