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Crossover points for JBL Lab q system

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Art Welter View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Art Welter Quote  Post ReplyReply Direct Link To This Post Posted: 16 December 2011 at 7:42pm
Originally posted by Requiem Requiem wrote:

Originally posted by Art Welter Art Welter wrote:


I would concur with that wiring scheme that it appears to be a proper passive crossover, though while you have the cabinet open it would be a good idea to test the HF separately from the 2445 (disconnect the 2445) and see if the HF acoustical crossover is indeed at 7K.

I will do, what would be the best way of going about this? connecting my amp and crossover, (got a void digidrive) and messing around with the crossover point until the 2405's cut in? or is there a better way?
Originally posted by Art Welter Art Welter wrote:


Still curious as to why an 8 rather than 6 was used, what was the wiring for the nl8 socket?

Pretty simple really, a + & a - going into the passive xover for the hf, a + and a - going down to the 12's and 2x + and 2x - going straight to an nl4 socket next to it for link out, however i doubt i will be using the link out so ive simply disconnected the nl8 as i dont have any of those leads, inserted anather normal speakon socket next to it, and now using a normal speakon in for the 12's and a normal speakon in for the passive x-over.

Cheers for your help its good to get a bit of backround & info on speakers i know absolutely nothing about! any idea on approximate worth? they are in very good condition for their age and origanal drivers etc throughout

The best way to check out the passive crossover would be to look at the response with a RTA or Smaart or any of many other test programs. Short of that, sweeping a tone, or the void digidrive should give you an approximate idea where the 2402/5 come in.

As far as the worth of the speakers,  the raw speakers probably would sell for more than the finished cabinets, old "point and shoot" speakers are not much in favor, and the ported W bin does not go very low by today's standards. Don't know the UK market for used drivers, but in the USA you might be lucky to get 25% of new cost for used ceramic magnet drivers.

I designed a proprietary system quite similar to the Lab Q, sold the company using the cabinets (Southern Thunder Sound, Inc.) off in 1992.
 I heard about ten years ago from a former employee that many of the cabinets had been stripped of drivers and thrown in a dumpster. Oh well..

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Requiem View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Requiem Quote  Post ReplyReply Direct Link To This Post Posted: 16 December 2011 at 8:31pm
Ah savage, i thought they would be worth quite a bit... anyway i didnt pay a lot for them so its all good. cheers for your help
www.requiem-soundsystem.com


Custom Martin Audio WSX, USB & CSG Soundsystem based in Bristol
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knet94 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote knet94 Quote  Post ReplyReply Direct Link To This Post Posted: 20 December 2011 at 4:36pm
If you can afford it take everything off the passive crossover and run them on separate amps with your LMS. I find that you get much better control on the HF that way. My current configuratiom is 5 way so sub bass 18s, kick bass 15s, midrange12s, Horns 2446s and bullets 2402s all on separate amps. It never sounded quite right to me with the bullets on a passive 7k high pass filter.

Edit

You can also set the delay individually for the comps & the bullets.


Edited by knet94 - 20 December 2011 at 4:56pm
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Requiem View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Requiem Quote  Post ReplyReply Direct Link To This Post Posted: 20 December 2011 at 10:42pm
Yeah i could do that, but for now im going to leave it as it is because i dont have a small amp to run the bullets. i do have a 75w per channel 1u amp but needs repair. cheers
www.requiem-soundsystem.com


Custom Martin Audio WSX, USB & CSG Soundsystem based in Bristol
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VECTORDJ View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote VECTORDJ Quote  Post ReplyReply Direct Link To This Post Posted: 14 December 2020 at 10:13pm
Hi, Sorry for being so late....Just found this story line...Is the Lab Q w-bin the same as the Keele JBL w-bin????  In photos on line it looks deeper????? Thanx,  VECTORSONICS
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