Seems to work perfect! Is the schematic digged in this thread? What is the woofer schematic?Originally Posted by Zilch
Seems to work perfect! Is the schematic digged in this thread? What is the woofer schematic?
It's a derivative of AM6212/00 for the HF, and N3134 for the LF. PM me for the tweaks I've done to them so far. I'll post the final version after I get it finalized.
Even though they're still crossed fairly high (~1kHz), these large horns bring a clarity to the midrange that the smaller ones don't seem to achieve. At the same time, they have full HF extension.
PT-H95 (on top of modded L200, right) is a close second. I'm still trying to get the more compact rectangular format and comparatively shallow PT-F95, which has lower distortion, comparable with 2381, according to the tech note:
http://www.jblpro.com/PD5000/PDF/PT_WaveGuide.pdf
If that would perform as well, it could be cut into this cabinet (inverted) nicely. If not, I'm not above having THESE beasts in the "Media room." I'll drape them with JBL Monitor Blue grille cloth for guests.
Being deep horns rather than flat waveguides, it's difficult to mechanically time align either 2352 or PT-H95. Not a terrible tradeoff, tho, from the way these big boys sound....
[Disclaimer: The use of Optimized Aperture 2352 horns and two-stage phase plug 243x drivers in combination is undocumented by JBL.]
The change for D8R2421 diaphragm on LE85 motor was radical, shifting the notch from 2.5 kHz to 8 kHz, and slightly modifying the Q.
The front-end impedance correction filter is now wrong (I'll measure and adjust that accordingly,) and I have to re-balance LF and HF SPL's, but the result is satisfying, achieved with no more HF "boost" than the original.
[O.K., maybe a teeny tiny bit more, ~0.5 dB at 20 kHz.]
The curves meet at 1 kHz, whereas the crossover frequency is 750 Hz, so I haven't messed with that.
HF is padded down 6 dB here, so I've plenty good room for SPL balance adjustment to taste.
Edit: Unpadded HF, bottom. Looks like it's nicely cooked, now....
My feeling is exactly my same problem adapation of 3145 network at my old 4343 driver...
The change for D8R2421 diaphragm on LE85 motor was radical, shifting the notch from 2.5 kHz to 8 kHz, and slightly modifying the Q.
The front-end impedance correction filter is now wrong (I'll measure and adjust that accordingly,) and I have to re-balance LF and HF SPL's, but the result is satisfying, achieved with no more HF "boost" than the original.
Edit: Unpadded HF, bottom. Looks like it's cooked, now....
anyway thanks soo much for sharing precious info.
Thanks, Jean.
Though CLIO is here now, these adjustements were done with the lowly Behringer UltraCurve RTA and mic.
I'll verify with quasi-anechoic CLIO once I get it running, of course.
Watch for the "CLIO Clinic" thread opening soon.
Thanks, Jean.
Though CLIO is here now, these adjustements were done with the lowly Behringer UltraCurve RTA and mic.
I'll verify with quasi-anechoic CLIO once I get it running, of course.
Watch for the "CLIO Clinic" thread opening soon.
mmmm new tool excitment!!!
check spec of mic clio...
especially in uhf
compensation curve is a most importance but it is not now time for talk of this excellent tool..
see you
and
Nice Work Zilch !
- Now, you've got nice looking curves with that horn-driver combo
- So you've altered the values of the LCR filter to move the notch upwards to a new center of 8000hz .
- What are the new values for this LCR ?
BTW ; ( & perhaps it's because I'm lefthanded ) / but when I first read this quote, I thought you were saying that the use of the 2421a diaphragm in the le85 motor / had actually caused the LCR to upwardly shift its' center frequency . ( That big "peak" at 8000 hz is still perplexing / unless the gauss level in the gap is somehow wrong . )
- That had me wondering what you were talking about since "series LCR" filters ( the way we use them ) are usually "pretty" tolerant to changes in the working circuit impedances .
My DIY 4430's, built in L200 cabinets are simply spectacular, and I have continued to read this thread, but sometimes wonder why. Now with CLIO you are going to take me somewhere I am not sure the wife would want me to go. I may end up having several more sets of JBL's. Sure hope so!!!
Hi Jack!I may end up having several more sets of JBL's. Sure hope so!!!
My pair of your modded L200's appears in most every system pic I have posted since building them. They're the standard against which I compare everything here.
Them and real 4430's, of course.
The only change I would make would be trying the PT-F95 waveguide, which JBL has never made in production, apparently.
Next time I open them up, I'm gonna add the contemplated bracing, as Mr. Widget heard some LF resonance in the boxes last time he was here listening to them.
Thanks, Earl.
Yes, that's the "Before" curve.
I'm listening to a big kludge on just one channel right now, but I ordered parts to do the mods to both for final evaluation.
Here's the HF circuits, original on top, revised below it, which generate the curves posted above:
- Yes, it's really quite inspiring to see you fix that large bump in the response .
- No doubt, many DIYers will find that their horn/driver combos need something like this addressed . ( Last spring I fixed a similar "booomp" in the response of my 288-8k/H14-50 combo / though, with none of the educational information which you continue to display here )
- Nice work !
Thanks, Earl.
Yes, that's the "Before" curve.
I'm listening to a big kludge on just one channel right now, but I ordered parts to do the mods to both for final evaluation.
Here's the HF circuits, original on top, revised below it, which generate the curves posted above:
do you have test if displacement of corrected zobel circuit change the final result ???
Not yet, Jean. I'll do it last.
Gotta unhook stuff and measure for that.
Today, I'm just listening without it.
I'm tweaked out for now....
Folks here gonna hafta help me with that input filter once I get the impedance curve, most likely.
What else I learned from this:
Driver/diaphragm swaps are not so trivial as many (like myself) might suppose....
Oh golly!
You mean they had reason for the plethora of different part numbers, the various cone and diaphragm kits?
It sure took you alot of time and money to come up with that considering I posted that very thing five freakin' years ago on the very first forum and then in every version of the forum since then.
In any case, some people need a visual along with a good rap upside the head with a 2 x 4 to get the drift.
Nice visuals Zilch. Carry on...
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