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JBL Signature series components

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Posted on April 29, 2000 at 20:04:53
Greetings!!! This is my first post! I haven't had much luck finding any useful info about building cabinets for my JBL Signature series(075 bullet tweeters & 15" D130 woofers)components! They are in excellent condition both sonically & appearance!!! I am wanting to built an upright design with the tweeter in-line & as close to the woofer as feasible. I am also wanting to up-grade my cross-overs with high-grade(best-sounding & minimal)components. I am using a Zen SET amp & a CD player & need a very efficient but great-sounding design!!!! Am I WASTING my time with these speakers or can I get some gratifing sounds? Thank you very much for any info or directions!!!

 

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Re: JBL Signature series components, posted on April 29, 2000 at 23:31:33
Kelly---Yo're not wasting your time, you'll get pretty good sound though personally I'd sell the tweeters and use the dough to buy some 2420 drivers and horns and cross to the D-150s at 800 or 1200 cycles, that would sound better yet IMO. Info on cabinets can be found at the JBL Pro website.

 

Re: JBL Signature series components, posted on April 30, 2000 at 16:43:13
Paul Joppa


 
Do you have some original JBL N2400 crossovers? I have a single N2400, which measures more like 1600Hz electrical crossover (not the nominal 2400Hz). This is a classic combination, a clear improvement over the "full-range" D-130s alone. (I can get the resistor and capacitor values, and estimate the inductances, if you need it.)

The only other combinations recommended by JBL in those days that used the D130 were with the small-format compression drivers (LE175/2410 or LE85/2420) with either the "potato-masher" or the HL-91 slant-plate lens. In those cases, the 1200-Hz N1200 crossover was used. I have a single old one, but it's potted in some kind of gook and I can't determine exactly what the component values are. The choke shunting the tweeter was tapped at 3-dB intervals for a high-frequency level control without resistors, a pretty cool trick. Otherwise I think it is basically a 12dB/octave standard crossover.

According to my JBL "Loudspeaker Enclosure Construction Manual" (Publication CF802; I can't find a date but probably late '60s) the following cabinet volumes and ports were recommended. Volume is in cubic feet, port is square inches.

Volume Port
4.1-5.0 25
5.1-6.0 35
6.1-7.0 50
7.1-8.0 65
8.1-9.0 80
9.1-10. 90

Be sure to brace the heck out of it - these big cabinets like to sing along with the music!

These things are a little colored, especially on classical. I find I get used to it pretty quickly, and I love the immediacy and dynamics. They are terrific with rock, and a lot of other stuff. I'm listening currently to 2220's (closely related to D130's) and the bigger drivers (2440) with the slant-plate lens, crossed at 800Hz. Life is grand.


 

Re: JBL Signature series components, posted on May 1, 2000 at 18:33:50
Hi Paul,

Great post - answered some JBL questions I've had. Could you be specific on what you call coloration? Based on a pair of WAF freindly cabinets I've obtained, I'm looking at putting together a 2-way, probably crossed over at 800 or 1000. D-130's are on my short list for woofers; are they a major part of the coloration, or are the horns the main source? Thanks.

 

Re: JBL Signature series components, posted on May 2, 2000 at 22:09:36
Wendell


 
Hello Paul,
Maybe you could help me out here I have a jbl n7000 crossover, the question that I have is what's the "+" and "-" hookups all it has is numbers 1-4. I can figure out the input but the output to LF, and HF is just numbered. Any help would be appreciated. Trying to hook up a 077 to a 375. Cabinets and drivers where purchased from a great guy that wanted the speakers to go to a good home. On my bass cabinets he is designing them to house a 8" jbl midbass driver and for the bottom end a pioneer 10". Going to use a marchand xm9 active crossover 3 way. Had to go with smaller bass drivers, cost and space(living in Japan has it's drawbacks, no room!!!). Amps that I will use are the paraglow, bglow, and thinking of using my 6550 push pull for the bass drivers or maybe use the orginal s.e.x. amp. Thanks for a response. Having fun.

 

Re: JBL Signature series components, posted on May 3, 2000 at 22:06:46
Paul Joppa


 
I can't really say, yet. My cabinets are old old stock Barzilay's, made of low-density particle board, and they jump and dance with the music - really need some major stiffening. The woofer range is fairly muddy, but pleasant in a euphonic way. No detail however.

I think the D130s can sound reasonably good if you don't go above 1200Hz with them, and don't ask for too much excursion. The will never have electrostatic clarity (!) of course, unless you drive a bass horn with them. Their linear excursion is quite small - the voice coil almost exactly fills the magnet gap. Maybe 2 or 3 mm. The cone breaks up very smoothly, so they have a rising response with frequency up to about 8kHz. It gets more directional and colored as you go up. I think the 2225 or 2235 woofers are much flatter, and probably cleaner (less audible micro-resonances and less subtle distortions), but they are closer to 96 and 93dB/w/m sensitivity where the D130 is 101dB or more. They'll rock you with a 2-w amp, which nothing else can do short of a bass horn.

The HF horn that I have is quite short - about 4" long with a 4" mouth. The compression driver adds another 4" to the length from diaphragm to mouth, but the mouth is small relative to a wavelength so there is some "organ-pipe" resonance. Some recent studies have indicated that as long as the pipe is shorter than 12", these resonances are not detectable as a horn honk, i.e. not especially unpleasant, but they are still there quite audibly. I found that I became accostomed to them in about 2-3 weeks. Other than that, the horn has great clarity and extremely low audible distortion, and I find those benefits more than outweight the colorations. I'm working on some ideas for a better solution, but that's where I am today.

Incidentally, I cross it over at 800Hz, but JBL did it as low as 500 on the old days. I believe that would exacerbate the horn loading problems, but I haven't actually tried it yet.

 

Re: JBL Signature series components, posted on May 4, 2000 at 19:02:54
Thanks for the info, Paul. I'm going to bi-amp (Dyna Mk2's on bottom, SE 45 on top), so I might just go with a less efficient woofer. Thinking of crossing more like 500hz.

My cabinets are '62 vintage Acousti-Craft, 4.5 cu ft, should be able to get it to 5.5 or 6 by replacing the back panel and boxing it out a bit more - adding a "bustle" so to speak. Constructed from cherry finish birch plywood, probably needs bracing, but very high WAF. There are LE14C's in them now - not my cup of tea. Still researching horns.

Kevin McDonald

 

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