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Thread: Anyone else using active X/O?

  1. #1
    4343mod
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    Anyone else using active X/O?

    Hey all,
    Just wondering if anyone else gutted the passive crossovers out of their cabs and went active. The whole HTPC thing has gone far what with multi-channel sound cards that offer configurable 6+ channel out (Lynx, RME, others?) and the few tweakers on DIY Audio that have developed hardware-based crossovers...Me, I'm just a mere mortal and use Behringer DCX2496 boxes.

    You are not stuck with those old dried caps and saturation-prone chokes, you know!

    I have been all over this in other threads of the past, now I'd like to hear what you have done to get some new with the glorious old. Go Vintage JBL!

  2. #2
    Maron Horonzakz
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    Been doing three way active for thirty years,,,

  3. #3
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    I have been doing it since 1975. The sound from an active crossover speaker is so much clearer, to me it is well worth the trouble. I am using 2 Altec 414 woofers for the bass, Altec 806/811 for the mids, and EV T350 super tweeter per cabinet, I am using an ancient DeCoursey crossover with plug in cards at 800Hz and 7kHz with 12dB/octave Butterworth. In restropect, I should've use 18db/octave.

  4. #4
    Senior Member louped garouv's Avatar
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    i am cobbling together another all active system...


    subwoofers are two dual 8" EAW boxes per side
    (they are EAW SB-48s)
    woofers are Altec 406As with passive radiators in a Bolero Box
    upper mids are Altec 802-8G on McCauley lens horns
    tweeters are JBL 076 and 075

    Here's the configuration for the crossover i am going to use...
    it's a vintage model EQR5 from a company called
    Sound Environments in NJ, i figure circa mid to late 70s vintage


    Input Section is:
    20Hz HP @ 18db/OCT to Sub-Bass
    20Hz HP @ 12db/OCT to Full Range


    Output sections are:
    Sub-Bass; 106Hz LP @ 18db/OCT - Normal
    +4.5db Boost @ 43Hz w rapid cutoff below - EQ Active
    Front Panel Control: Unity Gain @ 12 O'Clock. +10db at full CW rotation. Full off at CCW.

    Full Range 3-way Section
    Low; 1,200Hz LP @ 12db/OCT (derived from subtracting HP from FR)
    +6.5db Boost @ 65Hz w rapid cutoff below - EQ Active
    Mid-High; 1,200Hz HP @ 12db/OCT (no upper cut off)
    High; 6,500Hz HP @ 12db/OCT (no upper cut off)
    Front Panel Control: Unity Gain @ at full CW rotation. Full off at CCW.

    Tweeters; 7,000Hz HP @ 18db/OCT (no upper cut off)
    Front Panel Control: Unity Gain @ 12 O'Clock. +10db at full CW rotation. Full off at CCW.


    Hope this was helpful to you. My engineering opinion is that 12db/OCT in the mid band is the best slope for minimal phase aberration in an analog crossover. All filters are Butterworth except my active EQ's which are an elliptical filter of my design. I will try to find a performance graph and scan it for you soon. We can modify your unit to any cross points desired depending on your system requirements.

  5. #5
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    i just bought a THRESHOLD PCX unit. it is set at 18 db/oct from the factory. it comes w/ many x-over points. most importantly it came with 200hz, 250hz, 294hz cards/chips that will suit the jbl's that i have. i got it yesterday, so i have not listened to it yet. i am excited about its purchase. i WILL plug it in today...

    regards

  6. #6
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by RKLee View Post
    I am using 2 Altec 414 woofers for the bass, Altec 806/811 for the mids, and EV T350 super tweeter per cabinet, I am using an ancient DeCoursey crossover with plug in cards at 800Hz and 7kHz with 12dB/octave Butterworth. In restropect, I should've use 18db/octave.
    That sounds like about the best Altec system I've heard of on the forum. As an upgrade, I'd go with the 511 horn and keep the crossover frequencies the same. Well done!


    Widget

  7. #7
    4343mod
    Guest
    All sounds like exciting gear, men...
    Have those of you with vintage active X/O's retrofitted the caps or anything else?
    What are you all doing for amplifiers?

    (Crown studio reference 1 on the bass and Rane MA 6 on the MF, HF & UHF here)

  8. #8
    Senior Member Doc Mark's Avatar
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    Quote Originally Posted by Mr. Widget View Post
    That sounds like about the best Altec system I've heard of on the forum. As an upgrade, I'd go with the 511 horn and keep the crossover frequencies the same. Well done!


    Widget
    Hello, Mr. Widget,

    As I have a pair of each, 811 and 511, I've always wondered what the big difference between them is, besides the fact that one can supposedly be crossed over lower? In most of my older Altec information, Altec actually crossed over both of these horns at around 1200 HZ. Thanks, very much, for any thoughts, or comments on the performance of these two horns. I'm thinking about getting rid of one pair, and keeping one, "for a rainy day", and need to decide whether it's the 811's, or the 511's, that will hit the bricks..... or, should I just keep both of them, just for grins??!! Take care, and God Bless!

    Every Good Wish,
    Doc
    The only thing that can never be taken away from you, is your honor. Cherish it, in yourself, and in others.

  9. #9
    JBL Dog
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    Quote Originally Posted by 4343mod View Post
    Hey all,
    Just wondering if anyone else gutted the passive crossovers out of their cabs and went active. The whole HTPC thing has gone far what with multi-channel sound cards that offer configurable 6+ channel out (Lynx, RME, others?) and the few tweakers on DIY Audio that have developed hardware-based crossovers...Me, I'm just a mere mortal and use Behringer DCX2496 boxes.

    You are not stuck with those old dried caps and saturation-prone chokes, you know!

    I have been all over this in other threads of the past, now I'd like to hear what you have done to get some new with the glorious old. Go Vintage JBL!
    I'm using a JBL 5234A active crossover with factory 4343 cards for my 4343's. I guess you could call that 1/2 active, 1/2 passive since I'm still using the internal passive crossover for the mid, HF and UHF drivers. I don't think going 4-way active is anything I'm going to consider in the future.

  10. #10
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    i plugged in the threshold PCX last night.............men, what a difference. i HAVE NEVER heard the old 4343's sound THIS GOOD!!!!!!!! i can not begin to explain what a positive difference it made, top to bottom. the chips that i used are set at a x-over point of 296hz. i highly recommend using an external x-over..

    regards

  11. #11
    Super Moderator yggdrasil's Avatar
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    A while back I installed an active 2-way crossover in my 4-ways. At the same time I removed all unneccesary passive circuitry.

    On these speakers there are no way back.

    The crossover is DIY. 250Hz, 24dB/octave Sallen-Key.
    Johnny Haugen Sørgård

  12. #12
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    Quote Originally Posted by rj2077 View Post
    i plugged in the threshold PCX last night.............men, what a difference. i HAVE NEVER heard the old 4343's sound THIS GOOD!!!!!!!! i can not begin to explain what a positive difference it made, top to bottom. the chips that i used are set at a x-over point of 296hz. i highly recommend using an external x-over..

    regards


    that should be the one I was watching on Audiogon.
    I wasn't shure to buy it because the 18db slopes doesn't fit with my 4430.....
    Anyway this xo should be really great.
    It's a totally classA discrete opamp, and it is a Nelson Pass project
    I have the schematics of it, and I'm trying to figure out if it is possible to change the hipass to 6db instead of 18db
    Any help will be very welcome

    Michele

  13. #13
    Senior Member Valentin's Avatar
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    i am using DEQX active 3 way with lexicon 412 (bryston 8B) Amps
    with LSR 6332 monitors and the sound is spectacular no way back.
    i alsow have the active LSR subs but havent integrated to the system.

  14. #14
    Senior Member macaroonie's Avatar
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    This is mine

    If you have not seen this it is a start to finish build 300 ish project but fully active.

    http://audioheritage.org/vbulletin/s...ard+box&page=8

  15. #15
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    Fully active 4 way JBL 4350 ?!

    I have been thinking of going to a four way active xover system for a while now.

    My project is to build and test an active four way JBL 4350 and compare it with my standard JBl 4350 with its original passive 3107 xover.

    I have all the components 2235H, 2202H, 2441 and 2405H and intend to use two Behringer DCX 24/96 as active x-overs.
    The Behringers should be able to time align the different drivers take care of the phase shifting, provide the right xover frequencies and slopes plus equalizing if needed.
    I will use four amps with independent level controls also for additional flexibility.
    Testing could be accomplished by the Behringer DEQ 2496 and its RTA with dedicated microphone.

    Any suggestion? Is it a crazy trial or you think that would bring a benefit from cutting out the the old jbl 3107 crossover?

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