Simple Crossover Construction

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RuSsMaN
RuSsMaN Posts: 17,987
edited April 2003 in Speakers
Does anyone have a 'quick reference' guide for capacitors to be used as a high pass (1st order) for 8 ohm drivers?

For instance, cap value = xxxxHz @ 8ohm?

Cheers,
Russ
Check your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service.
Post edited by RuSsMaN on
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  • HBombToo
    HBombToo Posts: 5,256
    edited April 2003
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    do ya have a frequency in mind? I'll do some calcs befor I leave work...


    stike the previous
    check this out

    http://www.ptme.com/et/audio/reference/crossovers_passive/crossover6db.htm
    ***WAREMTAE***
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  • TonyPTX
    TonyPTX Posts: 545
    edited April 2003
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    Good info Bomb...I've been looking into installing some Vifa ring tweeters into an older set of JBL speakers that I have (the orginal tweeters have been sacrificed to the angry speaker gods a long time ago.) Problem that I see is that the Vifa is a nominal 4 ohm tweet, but the rest of the cabinet is designed for 8 ohms.
    Damn....8 lines...I've gotta put my sig on a diet now....
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  • HBombToo
    HBombToo Posts: 5,256
    edited April 2003
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    Originally posted by TonyPTX
    Problem that I see is that the Vifa is a nominal 4 ohm tweet, but the rest of the cabinet is designed for 8 ohms.

    I'm not following here... howsa bout some detail?
    ***WAREMTAE***
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  • RuSsMaN
    RuSsMaN Posts: 17,987
    edited April 2003
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    Are you drunk already Hbomb? He wants to replace an 8ohm tweeter in an old JBL cab, with a 4ohm Vifa.

    So basically, what can he do (resistor wise?) to get the other speakers to 4ohm?

    The wifes grandma HATES her little KLH ceiling mounted speakers, so I figured I'd throw together some big, cheap 3-ways. All 8 ohm drivers, all around 90db eff. I have a 12" Pioneer woof, 23-1500Hz (I will just run it fullrange), a Sony 5.25" mid, 90-6000Hz (I will use a 220uf cap to pass it at 90Hz or so), and a Motorola Piezo, 3500-22000Hz (I have some 4.7uf caps to pass it around 4500).

    Anyway, thats the plan, pics to come. Once all is said and done, I'll have maybe $20 in the pair.

    Cheers,
    Rooster

    Ps, cool link btw, JUST what I was looking for.
    Check your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service.
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  • HBombToo
    HBombToo Posts: 5,256
    edited April 2003
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    check this link out!!! Major Cool Factor.

    http://www.mhsoft.nl/spk_calc.asp#crossover

    Oh, in that case all that would need done would be to put an 8Ohm resistor in parallel with the tweet and it would become 4. Now the trick here would be to find the combination of resistors that can hit 8Ohms and handle the power.

    Whatch out for piezo's...
    ***WAREMTAE***
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  • RuSsMaN
    RuSsMaN Posts: 17,987
    edited April 2003
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    I'm not worried about the Piezo's, she's 86 years old, with a 50w Pioneer, listening to old Victrola LP's.

    DUDE, its a FOUR OHM tweeter, going in an 8ohm speaker cab. Are we following each other? He either needs to get the cab to 4ohm, or get the *new* Vifa tweet to 8ohm.

    Cheers,
    Rooster

    2 bass ales down, 3 shots of Canadian whiskey.
    Check your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service.
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  • rs159
    rs159 Posts: 1,027
    edited April 2003
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    Take two Vifas and wire them in series. :)

    Don't know what that would do for imaging, though.
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  • RuSsMaN
    RuSsMaN Posts: 17,987
    edited April 2003
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    Don't think that had not crossed my mind. He could even wire one in or out of phase, rear-firing.

    Cheers,
    Rooster
    Check your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service.
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  • rs159
    rs159 Posts: 1,027
    edited April 2003
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    Sounds too much like the "b" manufacturer to me.
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  • RuSsMaN
    RuSsMaN Posts: 17,987
    edited April 2003
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    C'mon now, a lot of good di/bi pole mains out there.

    I never said 'direct-reflecting', that's my story, and I'm sticking to it.

    Cheers,
    Rooster
    Check your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service.
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  • rs159
    rs159 Posts: 1,027
    edited April 2003
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    Originally posted by RuSsMaN
    C'mon now, a lot of good di/bi pole mains out there. ...Cheers,
    Rooster

    I know, I guess I should'v used one of these: ;)
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  • VR3
    VR3 Posts: 28,052
    edited April 2003
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    Def Tech's Kick arse man!

    Edit: This is relevant due to the fact they mentioned BiPolar Towers!
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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  • RuSsMaN
    RuSsMaN Posts: 17,987
    edited April 2003
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    Stick to your opinion (ie DefTech di-pole configs), loose the effin emoticons, no one cares to see that crap. Not in this thread, let's keep it network related.

    An effin smily, mixing on 2 turntables with headphones on, what does it have to with ANYTHING mentioned here? Make it relevant, or don't make it all, and I say that with all due respect.

    Any thoughts on caps/ 1st order crossovers? Or perhaps how to integrate a 4ohm tweet in an 8ohm speaker?

    Cheers,
    Rooster
    Check your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service.
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  • VR3
    VR3 Posts: 28,052
    edited April 2003
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    Di-Pole what? Def Tech's are BiPole towers. I commented that there are good BiPole speakers out there.
    Smilies are cool man, but Ill keep them out of the forum except for off topic! Goodbye! Run em in series as said above.....
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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  • RuSsMaN
    RuSsMaN Posts: 17,987
    edited April 2003
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    Can you tell me the difference in di/bi pole? Without looking it up?

    For that matter, the difference in series and parallel?

    Cheers,
    Rooster
    Check your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service.
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  • VR3
    VR3 Posts: 28,052
    edited April 2003
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    Im not sure ex-zachery on the series and paralell, but I think bi-pole is a more direct sound, while dipole is a more offset sound.....not 100% sure. Bipole's would be good for back surround, and the dipole's would be good for side surrounds. I think.....:confused:
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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  • rs159
    rs159 Posts: 1,027
    edited April 2003
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    Dipoles have their front and back waves out of phase and with bipoles they are in phase. That would explain what you said "more direct sound". Because the sound is out of phase it makes it harder to localize the actual speaker in a dipole system. That effect is only relevant if your ears are perpendicular to the main axis of sound being created by the two radiating sides of the speakers. If you use dipoles (e.g. electrostats or *gasp* bose speakers) for mains the only non localized effects will come from the extra reflected sounds. ¿Comprendes?

    Series and parallel are wiring techniques. If you want a long **** explanation then click here
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  • VR3
    VR3 Posts: 28,052
    edited April 2003
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    me comprehend, like I said, bipole.....direct sound......dipole...not direct....see......simple....
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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  • rs159
    rs159 Posts: 1,027
    edited April 2003
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    Ok then, so what's the impedance of a subwoofer if you wire three 6ohm drivers in parallell?
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  • VR3
    VR3 Posts: 28,052
    edited April 2003
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    I didn't read the link but my guess it 16 ohms! *lol* I dunno, I'm just not interested to learn stuff I do not plan to do or buy. I don't plan to buy Di/Bipole speakers, and I don't plan to run series or paralell. When I decide to buy Di/Bipole speakers I will open the books and pound it into my brain.
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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  • rs159
    rs159 Posts: 1,027
    edited April 2003
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    16!?!? It's TWO!

    My advise, don't get into car audio. Or get somebody to do it for you. I can see it now - MX's phat new system with four 4ohm twelves wired in PARALLEL! Which gives his poor amp a ONE OHM LOAD!

    Kaboom!
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  • VR3
    VR3 Posts: 28,052
    edited April 2003
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    RS, I truly in all respects don't plan to get into car audio. Car Audio to me seems to be an expensive hobby that will only lead to major hearing loss. If I add anything it will be a small subwoofer. That will be it.
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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  • rs159
    rs159 Posts: 1,027
    edited April 2003
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    And home audio isn't expensive? If you get a quiet enough car you shouldn't have to play it too loud. It's true that adding a sub will have a dramatic effect on most OEM systems, but getting quality fronts can be just as dramatic, especially if the car's system was just a 5 watt cassette deck and some no-name full rangers with nothing but "Japan" printed on the baskets. Add some amps and you're in heaven. If it were me, I would try to improve the overall sound first, and search for lost bass later. A $20 boombox with a subwoofer rigged up to it still sounds as bad as a $20 boombox, just with better bass. Of course if the car's system is OK to begin with then boom away.
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  • burdette
    burdette Posts: 1,194
    edited April 2003
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    So what was/is the final word? Are you going to wire a 4ohm resistor in series with the 4ohm tweeter?

    I'd recommend trying several resistors one at a time, maybe from 3 to 6 ohms, and choose the one that gives the best sound. Of course, you'd also have to have different values of capacitors to cross at the same frequency as you change resistors. You could also try a potentiometer in series with the tweeter. If this is sort of a seat-of-the-pants project, maybe the changing xover frequency isn't a big deal.
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  • TonyPTX
    TonyPTX Posts: 545
    edited April 2003
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    Good info here. I wasn't planning on doing this anytime soon. I've got to dedicate money to more important gear in my system for the time being. When I get time to do some real considerations, I'll bust open one of the JBL's and get a quick schematic of the X-Over so that I know what I'm working with.

    Tony
    Damn....8 lines...I've gotta put my sig on a diet now....
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