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jerv
05-30-2006, 12:31 PM
Hi all - I'm new to this forum.

I`ve recently picked up a pair of JBL LE14A drivers, and wish to use these in new speakers in my living room. The T/S-parameters indicate good results in approx. 60 ltr reflex cabinets tuned to about 40 Hz.

Now for mid/high frequency drivers. In old JBL designs they took this driver all the way to 2K (was it the Lancer 99?), but that was then....

Does anyone have experience with the upper frequency response of the LE14? What midrange/high frequency driver(s) / horns could go with the LE14's? Cone? Compression?


Thanks.
EspenE
Norway

Zilch
05-30-2006, 01:42 PM
Lancer 99 and others crossing the LE14 so high are responsible for LE14 earning an erroneous reputation for "muddy" midrange. Actually, the LE14 variants offer one of the most versatile and musical-sounding drivers available, when properly applied.

There is plenty of infomation on LE14 projects in these forums. Use "Search" to find them.

To answer your question more directly, they may be used up to 1.2 kHz nicely, perhaps a bit higher. I use them routinely in two-ways crossed in the 1 kHz range, and also as moderate-power subs.

http://audioheritage.org/vbulletin/showthread.php?p=92383#post92383

Even S99 can be "fixed" (front, left.)

I don't think you've necessarily found the optimum cabinet size or tuning yet, which may depend upon what you want to build and how you want to use it.

Also, you'll very likely have to deal with replacing the old Lansaloy surrounds on LE14A's if that hasn't been addressed already....

Mr. Widget
05-30-2006, 03:06 PM
Hi all - I'm new to this forum.

I`ve recently picked up a pair of JBL LE14A drivers, and wish to use these in new speakers in my living room. The T/S-parameters indicate good results in approx. 60 ltr reflex cabinets tuned to about 40 Hz.

Now for mid/high frequency drivers. In old JBL designs they took this driver all the way to 2K (was it the Lancer 99?), but that was then....

Does anyone have experience with the upper frequency response of the LE14? What midrange/high frequency driver(s) / horns could go with the LE14's? Cone? Compression?
If you are used to the quick midbass of smaller systems you may find that the LE14A is sluggish or thick sounding above 500Hz. If you like the sound of many of the vintage JBL and Altec systems, you can likely push the crossover point as high as 1KHz. I prefer a speaker with a bit more snap to it. In any case the low end from the LE14A is quite nice.

I'd probably go with an all direct radiator system along the lines of the JBL 250 series systems.


Widget

jerv
05-31-2006, 07:49 AM
Thanks for help.

I have now browsed the forum extensively, and found a lot of interesting information for my intended application. Especially info concerning the PT Waveguides.

However, I have not found any information on PT Waveguides on www.jblpro.com (http://www.jblpro.com) - nor any info on pricing, availability, vendors etc. (To my knowledge: these products are not sold here in Norway). Where do you guys buy these waveguides?

Thanks, EspenE

Zilch
05-31-2006, 11:14 AM
http://www.jblpro.com/ae/pdf/PT_WaveGuide.pdf

They are used extensively in the AE series products.

I look up the individual product technical manuals at www.jblproservice.com (http://www.jblproservice.com) to get the part numbers, then order through JBL Pro Parts.

Your JBL Pro dealer can get them, once you know the part number(s) you want.

There are several recent threads wherein members are exploring them.

See here, for example:

http://audioheritage.org/vbulletin/showthread.php?t=10934

Presently, I am playing LE14H-3 in 2 cuft. (~60 L) tuned to 30 Hz with 2426H on the cheap ($9.90) 1" thread-on PT-F95 waveguide. LE14A plays fine in that setup, too.

The 1.5" PT waveguides in different patterns work well using JBL's companion throat adapter for 1" drivers.

I've again posted the biased (~1 kHz) HF crossover schematic I'm using with these in the forum recently:

http://audioheritage.org/vbulletin/showpost.php?p=111803&postcount=19

jerv
05-31-2006, 11:31 AM
Thanks, Zilch!

Yes, I already found the PT Waveguide White Paper on jblpro.com. Now to explore www.jblproservice.com (http://www.jblproservice.com) to get the part numbers, then to find out wether there is an JBL Pro dealer here in Norway.....

The speakers goes into my living room. I may be going for the 90x90 waveguide - probably the PTF-1010 HF. Crossover at about 1Khz, electronic w/biamping. I make all the electronics myself.

You are certainly right about the not optimal reflex tuning - but 60-70 ltr is about the limit of what I can fit in my room....

EspenE

Zilch
05-31-2006, 11:52 AM
Yes, PT-F1010 is the one I like best. I'm installing one in an L200 in my avatar here:

<------

For LF filter, I'm still using the simple 4430 circuit; I haven't gotten around to optimizing the Zobel for LE14 variants yet. There's more improvement to be achieved with doing that, or active crossing and biamping as you plan to do, most likely.

You haven't told us what HF driver you're going to use....

jerv
06-01-2006, 02:18 AM
You haven't told us what HF driver you're going to use....

I’m not sure yet. Though I have built a number of systems through the years, this is my first journey into the world of “pro” drivers and compression tweeters – which I up to now always have associated with harsh sounding PA systems on rock venues. This understanding might well be wrong.

I am intrigued by loudspeaker directivity and polar response – and therefore of waveguides combined with low crossover frequencies. In have experience with dome tweeters mounted in round, shallow waveguides with 90/90 coverage. This seems to work well in my application (ordinary living room – 3m listening distance) – but the power handling and need for high crossover frequencies of conventional dome tweeters is a limitation.

In other words: I am looking for a waveguide/driver combination which handles 90/90 dispersion and can be crossed at 1 kHz or lower. I have my own measuring equipment, and make my own electronic crossovers – including notch filters and compensations. I also use Behringer EQ.

This is probably heresy on this forum – but the BMS drivers (especially the 4552ND) has been recommended by many. I know little (yet) of JBL compression drivers. What can be recommended?

Thanks, EspenE

Zilch
06-01-2006, 11:13 AM
Start with JBL 2426H and JBL throat adapter for PT waveguides.

JBL 243x 3" diaphragm drivers bolt directly on. Plenty of info on them in these forums. That's 2431H in my avatar.

Some JBL 245x 4" drivers are also bolt-on. "SL" Aquaplas damped diaphragm versions recommended. Expensive.

*****

BMS 4552ND requires two throat adapters with 1.5" PT waveguides. That works, tho.

BMS 4555 bolts directly on 1.5" PT waveguides with additional mounting holes added to the flanges.

I cross BMS at 1200 Hz successfully, easy compensation. 800 Hz is too low, in my experience. One kHz is a "maybe," only minimally attempted here....