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Thread: JBL L7s and Bi amped - Crossover setting question

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    JBL L7s and Bi amped - Crossover setting question

    Hi experts, I have a pair of JBL L7s bi-amped with a Denon AVR and an HK Amplifier. The Denon runs the main 3x way speakers on the L7s, and the HK Amp is running the sub outs on the Denon to the 12"s on the L7s. My question is regarding the Sub crossover settings. Manual says the crossover setting between the 12"s and the 8"s is 180Hz. Is that where I should set my crossover for the sub setting on the AVR? Most recommendations always say 80Hz everywhere I see. Thoughts?

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    Senior Member HCSGuy's Avatar
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    Your question could be answered two ways. First, what hookup method would best match the designer’s intent when the speaker was built in the early 90’s, and second, what sounds best for how you use the speakers now?

    To answer the first, these were designed at the beginning of surround sound - no matching center speaker was ever made for them. If you think of them as music speakers, and you are trying to get the original sound out of them, do not use any additional crossover - the speakers have a 180hz non-defeatable passive crossover built in. One option would be to connect the HK amp to the front (full range) preamp outputs of your receiver, let the passive crossover cut everything starting at 180hz, and hopefully the HK amp has gain controls that you can use to balance the bass to the rest of the system. If not, second option would be to let the HK run the speakers full range - connect it to the front preamp outputs of the receiver, then put the bi-amp straps back on, disconnect the receiver speaker leads from the speakers, and just use the HK amp to power the L7’s. This will probably be your best bet for music sound quality.

    However, the woofers in the L7’s go pretty low, and take a lot of power, so if you’re using them in a surround sound video system, why not treat them as a subwoofer and LCR in one cabinet, which is what you are doing. Without opening them up and bypassing parts of the speaker, the 180hz crossover point will remain, so you’re going to have to do some experimenting. If you don’t have a separate sub, and are using the L7’s as subwoofers, you can set the crossover closer to 80hz on your receiver, and connect the HK amp to the sub out on the receiver as you are doing. This does leave you with two cascaded crossovers, but since we usually crank up the gain on subwoofers, the actual output one octave up, at 160hz, may still be close to what you would get in example one, so you may not hear a “Suck out”. If I was doing this, I would probably still configure the front speakers as “Large” on the receiver, and set the subwoofer output to LFE+L/R, so that the bass output is duplicated, even though the top half of the L7’s will still start cutting the bass out of the 8” mid-bass at 180hz (probably at 12db/octave). This is probably the way you have it now, so put some well recorded music on and do some listening, and tweak as necessary.
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    Quote Originally Posted by HCSGuy View Post

    To answer the first, these were designed at the beginning of surround sound - no matching center speaker was ever made for them. .
    you are almost correct on both statements, but as I've read ... the JBL CL-505 was later designed as that missing/matching center for HT duty.
    Some kind of happiness is measured out in miles

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    Quote Originally Posted by HCSGuy View Post
    Your question could be answered two ways. First, what hookup method would best match the designer’s intent when the speaker was built in the early 90’s, and second, what sounds best for how you use the speakers now?

    To answer the first, these were designed at the beginning of surround sound - no matching center speaker was ever made for them. If you think of them as music speakers, and you are trying to get the original sound out of them, do not use any additional crossover - the speakers have a 180hz non-defeatable passive crossover built in. One option would be to connect the HK amp to the front (full range) preamp outputs of your receiver, let the passive crossover cut everything starting at 180hz, and hopefully the HK amp has gain controls that you can use to balance the bass to the rest of the system. If not, second option would be to let the HK run the speakers full range - connect it to the front preamp outputs of the receiver, then put the bi-amp straps back on, disconnect the receiver speaker leads from the speakers, and just use the HK amp to power the L7’s. This will probably be your best bet for music sound quality.

    However, the woofers in the L7’s go pretty low, and take a lot of power, so if you’re using them in a surround sound video system, why not treat them as a subwoofer and LCR in one cabinet, which is what you are doing. Without opening them up and bypassing parts of the speaker, the 180hz crossover point will remain, so you’re going to have to do some experimenting. If you don’t have a separate sub, and are using the L7’s as subwoofers, you can set the crossover closer to 80hz on your receiver, and connect the HK amp to the sub out on the receiver as you are doing. This does leave you with two cascaded crossovers, but since we usually crank up the gain on subwoofers, the actual output one octave up, at 160hz, may still be close to what you would get in example one, so you may not hear a “Suck out”. If I was doing this, I would probably still configure the front speakers as “Large” on the receiver, and set the subwoofer output to LFE+L/R, so that the bass output is duplicated, even though the top half of the L7’s will still start cutting the bass out of the 8” mid-bass at 180hz (probably at 12db/octave). This is probably the way you have it now, so put some well recorded music on and do some listening, and tweak as necessary.
    I have an N Center and its "passable" I guess. Also tried a Polk CS10 and its was so skewed to higher frequencies it was maddening. I do need to do some testing with "quality" recorded sources, and have a phono cartridge and turntable in the mix soon. So far I do trust the Denon Audyssey a bit more than the previous Onkyo, and if I recall w/out checking is set the sub crossover at 180Hz. Cant locate my old Chesky and Telarc demo CDs from my old Circuit City days when I sold those, and the spotify streams of good material are empty, at best. It really sucks I cant get the 3x3' of clearance around them no matter what in my room, either. The idea of using my HK for Main and binding the lo/hi together may be an option, but I need to check on options on the Denon. Sure wish HK would have not bailed on the AVR game. Denon and Onkyo are so lacking in warmth. Back to the dreams of a dedicated HT room I guess.......

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    Senior Member HCSGuy's Avatar
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    Quote Originally Posted by BMWCCA View Post
    Thanks for the reminder - been years! As the links describe, there is a jumper on the bass crossover that is on the back of the speaker terminal. If you are using the crossover in your receiver (or an external, active crossover), pull the jumper and it will bypass part of the bass crossover. The woofer will still have a Low Pass crossover on it, but it will be 1st order at 150hz instead of 2nd order. You may find it sounds better this way. I no longer have L7’s around, so I can’t play with this, but encourage you to. However, from looking at the schematic, this jumper does not change the 180hz crossover on the mid bass, so you still have to fill that hole, so to speak. DaveinFV, if you get bored, look at the L7 thread BMWCCA linked to - it’s really long, but may be helpful.
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    Senior Member HCSGuy's Avatar
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    Quote Originally Posted by SEAWOLF97 View Post
    you are almost correct on both statements, but as I've read ... the JBL CL-505 was later designed as that missing/matching center for HT duty.
    When I sold the L series at Circuit city, up until I think the end of ‘95 (I think), we had 3 center speakers to sell; a POS AudioSource, a Harman Kardon Center (model number, I think, “Center”), and an Infinity center, in a honey oak cabinet that was pretty unsellable. We would break up a pair of L1’s and sell a single for the center speaker, or sell the HK one. I think, though, that “Matching” meant something different back then than now. Dolby Pro-Logic sold the center speaker as the “Dialogue” speaker, so you wanted a speaker that made it easiest to hear what people on screen were saying, but there wasn’t really a push to make a seamless image across the front three speakers until THX came, originally requiring identical, vertical LCR speakers, most of which sounded pretty bad on music. I point this because JBL saying the CL505 “matched” the L series was more because it was black, not because it was designed to go with them. It used different, much cheaper drivers with a different crossover point. However I will concede that I have never heard one, so maybe if you put it next to them, it really works. I just don’t know.
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    Senior Member HCSGuy's Avatar
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    Quote Originally Posted by daveinfv View Post
    I have an N Center and its "passable" I guess. Also tried a Polk CS10 and its was so skewed to higher frequencies it was maddening. I do need to do some testing with "quality" recorded sources, and have a phono cartridge and turntable in the mix soon. So far I do trust the Denon Audyssey a bit more than the previous Onkyo, and if I recall w/out checking is set the sub crossover at 180Hz. Cant locate my old Chesky and Telarc demo CDs from my old Circuit City days when I sold those, and the spotify streams of good material are empty, at best. It really sucks I cant get the 3x3' of clearance around them no matter what in my room, either. The idea of using my HK for Main and binding the lo/hi together may be an option, but I need to check on options on the Denon. Sure wish HK would have not bailed on the AVR game. Denon and Onkyo are so lacking in warmth. Back to the dreams of a dedicated HT room I guess.......
    I do remember HK receivers sounding very good, and breaking very often. I remember going to year after year of Denon or Yamaha training, and every year the receivers would get lighter, power would go down, but there would be more video features, as that was what customers were demanding. I do still think Yamaha’s $1000+ receivers sound better than Denon/Marantz or Onkyo/Pioneer, but are not as reliable.

    L7’s are notoriously picky about placement - again, read the L7 thread. If you can’t get them to sound good, don’t sweat it; get something else. Many people had better luck with L5’s and a subwoofer.

    Regarding center speakers, you might try looking for a performance series PC600. They still pop up on CL and EBay, sometimes still in the box, for a good price. They look a little funny, but have one of the best JBL tweeters in them.
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    Senior Member gferrell's Avatar
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    This was my solution to the center channel. I'm still using it with my XPL series.

    http://www.audioheritage.org/vbullet...(1990s)/page24
    XPL 200's w DX1, XPL 160's, XPL 140's, L7's, L5's, L3's, L1's Homemade L Center, 4412's, 4406, L60T's, L20T's

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    Quote Originally Posted by HCSGuy View Post
    Regarding center speakers, you might try looking for a performance series PC600. They still pop up on CL and EBay, sometimes still in the box, for a good price. They look a little funny, but have my favorite JBL tweeter in them.
    this is my center. ==>> http://www.audioheritage.org/vbullet...hlight=deftech

    It is so good, that often when watching just TV and not needing the full 5.1 , will just
    run the center alone.

    The built-in amp and 8 inch sub really give a full, nice sound. Essentially mono,
    but that's OK for some situations.
    Some kind of happiness is measured out in miles

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