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JBL 4828 |
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angrykid ![]() Registered User ![]() ![]() Joined: 03 December 2009 Location: Rickmansworth Status: Offline Points: 216 |
![]() ![]() ![]() ![]() ![]() Posted: 24 October 2010 at 9:48pm |
Has anybody got a passive crossover for a JBL 4828 or a wireing diagram for the PCB? I know it's prob a long shott as their either non existant or like rocking horse shit! Cheers
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jbl_man ![]() Moderator Group ![]() Joined: 12 January 2005 Location: London. Status: Offline Points: 11122 |
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Ben,here is the spec of the cabinet..it crosses over at 800hz,so you could allways subsitute it for a similar passive xover.,as i dont think you will ever find an original.
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Be seeing you.
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_djk_ ![]() Old Croc ![]() Joined: 23 November 2004 Location: United States Status: Offline Points: 6002 |
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"
Ben,here is the spec of the cabinet..it crosses over at 800hz,so you
could allways subsitute it for a similar passive xover.,as i dont think
you will ever find an original."
It is a very special crossover, a standard crossover will not work well. http://www.jblproservice.com/pdf/SR-Series/SR4722A.pdf You should either use the SR4722A crossover, or what I used, a 4435 high-pass and a custom low-pass. http://www.jblproservice.com/pdf/Studio%20Monitor%20Series/4435LR.pdf IIRC, I used the low-pass from this: http://www.jblproservice.com/pdf/SR-X%20Series/SR4722X.pdf |
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djk
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_djk_ ![]() Old Croc ![]() Joined: 23 November 2004 Location: United States Status: Offline Points: 6002 |
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djk
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angrykid ![]() Registered User ![]() ![]() Joined: 03 December 2009 Location: Rickmansworth Status: Offline Points: 216 |
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_djk_ ![]() Old Croc ![]() Joined: 23 November 2004 Location: United States Status: Offline Points: 6002 |
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Obviously, if you don't also need the bi-amp capability you could omit some parts (the switches and the 20µF+0.1µF cap).
You don't need the 0.1µF in parallel with the 2x12F in the woofer circuit. The other 0.1µF caps are for the best audiophile performance, good polypropylene caps (without the 0.1µF bypass) may be good enough for PA use. You might be able to eliminate the upper of the two pads, I had to run it wide open to get the high end flat to 16Khz. On the other hand, you may want the capability to roll-off the high end a bit. The lower pad is the midrange level. ----------------------------------------------------------- Mine were killer for hi-fi with an 18" sub below 100hz. Worked well for small DJ jobs too. Edited by _djk_ - 01 November 2010 at 12:23am |
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djk
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Riley Casey ![]() New Member ![]() Joined: 17 January 2014 Location: MD Status: Offline Points: 1 |
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I hope no one used the 800 hz suggestion in building passive crossovers for 4828s. The horn won't load the driver below 1khz. The SR4722 also uses a smaller version of the Dolly horn and a different ( cheaper ) HF driver and needs to crossover even higher. A search for a JBL 4726 will get you a schematic for a crossover that is the closest match you're likely to get for the 4828 and crosses over at about 1k6 hz. I'd post the schematic but the forum isn't giving me the option for images. The studio monitor 4430 crossover is very hifi but crosses over at 1khz to give the 15" woofer some chance of meeting the HF horn but I wouldn't want to drive a 1" compression driver very hard at that low a frequency and its a bit dubious if the low pass filter would be a good match for the 12" 2204H or 2206H woofer in the 4828 ( depending on when it was made) Another caveat in using the 4430 crossover schematic is that the HF driver in the 4430 is an 8 ohm 2426J while the driver in a 4828 is a 16 ohm J version.
In my experience JBL tends to build passive crossovers for live sound speakers with driver survivability as the first consideration and performance second. I've been bi-amping the 4828s at 1300 hz for for years with good results both in my living room and for use as stage monitors. Zombie threads R us
Edited by Riley Casey - 20 November 2023 at 2:15am |
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