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I'm noticing that there are some missing notes in the mid-range with my jbl 2441's. I know the notes are in the music 'cuz I heard them before with other speakers, both reflex and horn. Either the notes are being glossed over or they're just not being reproduced. Will changing the wiring to the drivers with something other than Radio Shack magnet wire help this? Is it perhaps the capacitor in the mid-range circuit?
Follow Ups:
I've spent some time reversing polarity on the 2441's. I don't think I have them out of phase.
I do have the positive side of the xover connected to the black terminal on the 2441, which I believe to be wired reverse polarity.
As originally wired, the bass (I've left the sub off for all of this) sounds tight and full. Things seem to blend well from the mid-bass right up through the Fostex tweeters.
When I reverse the polarity on the 2441's the bass is more reserved and I hear the Fostex come more to the front. I also hear a bit more sweetness in the upper end of the midrange.
So, I'm going to try and confirm with Jammin Jersey which diaphragms I have. I don't want to pull the drivers apart if I don't have to 'cuz they really sound pretty damn good.
I've got some Solens caps and inductors coming to do some simple experiments with the xovers.
I'm really glad I left the xovers exposed on pieces of plywood. Makes life much easier through all of this.
In case of confusion, the Black post is POSITIVE on the 2441 and the 2480/82.
Radian Al Diaphrams do an excellent job and are reputed to bring the 2482 to 2441 spec.
Whatever, they do an excellent job of handling mid duty.
pc
If the midbass and midrange drivers are out of phase, the null at 500Hz is very deep and wide. Try borrowing an octave band hand held spectrum analyzer and measuring the system. Even with an octave band analyzer, the null will show up easily. You can try reversing the midbass polarity and see if the sound is fuller. The fuller sound quality indicates that the null is not present. Even though an octave band or a 1/3 octave analyzer may be expensive, they are a great help with sorting out problems.
You can check a cone midbass driver with a battery, but I wouldn't check a compression driver with a battery.
nt
Dan, I have spent a lot of time with the 2441's and think they are quite good. I agree with Bill that the culprit is most likely the crossover or phasing. It would be very easy to just reverse the 2441 connections and see if it sounds better.
Upgrading the wiring and or capacitors will certainly help the overall sound but probably would not help with what you are describing.
The standard aluminum diaphragms sound good. Others have experimented with other diaphragms but the stock ones seem to best. I had great success with cryo treating the diaphragms. A very nice improvement.
Chris
Chris, I still remember how great your's sounded when I was out there last year. Oh wait, maybe it was the 'tables. :)
I'm not real good at expressing my goals in audio terms but I think my thoughts are starting to get through. I'm really happy with the way the 2441's sound, however, I'm still learning how to get the most from the horns. This is the only area that I've felt like could use some improvement, so far. And I'm really pickin' nits here!
Is one perhaps more suited to home audio?
I have never, ever heard a titanium diaphram that I considered appropriate for actual listening purposes, as opposed to the high power applications of pro sound for which they were designed.
I would switch to aluminum if you can.
Jonathan
I picked up a pair of Ti diaphragms for a pair of 802D's. I could not tell much difference between them and a pair of original Al's in another pair of 802D's. Lots of variables in there but it is not a slam dunk that Ti's are bad. I got them from Aussie land and the price was right.
Jim N
Which was, should I expect details to be somehow drowned out by this particular compression driver?
I've read where some claim to have improved transparency, detail retrieval, etc. with upgrades to the wiring between the crossover and the drivers. In this case it seems to be the mid-range driver that is not getting all of the details out.
Missing detail is far more likely to be a problem in the mids than the HF, and I'd still be looking at the crossover as the culprit, especially if second order. Check the driver polarities, you may have a phase response notch. Time mis-align between the HF and mids is a possibility too. Or both the above.
First order xover. The 2441's are run with the polarity reversed. I believe it is a 40 uF GE oil cap in the mid.
definitely look around for an impedance graph of the 2441... i'd bet you're stressing that diaphragm pretty hard with a 40uF cap, because chances are good it's not running at nominal impedance down at 500 hz too (which i'm betting is your theoretical crossover point).
are the mids sounding particularly grating and forward? if so-- you're probably overlapping like mad with your woofer, and you're suffering major cancellations and wierdness- not to mention distortion!
d.
However, the mid is padded down ~6db. Most info I can find says 500 Hz is the low cut-off. Not that it couldn't be better! :)
hey dan-
don't always sweat 'what most info' says- due to the internet, there's a TON of misinformation out there--- getting horns to sound remotely human is practically a 'by feel' pursuit-- nice measuring tools are great demystifiers, but also present their own problem negotiation set.. 'cause you have to learn not to be tricked by what you're measuring! not to say it's not worth learning, mind you.. but a minimal investment in that'll save you a lotta money in time and caps, resistors, and coils..
it took me almost 2 years to get a decent result out of my horns.. which almost killed me, and i swear i almost gave up multiple times out of frustration. but: rules that made a big difference-
1)run your horns at least an octave above their cutoff.
2) with first most crossovers-- it pays to leave a gap between drivers in your knee points.. it's easier working back to 'good' with smaller caps than needing to rebuild the entire thing.. you'll notice a gap in the middle is a lot less grating than overlap.
3) use oil caps rated at 100v...200 at most. don't overrate 'em.. it sounds horrible by comparison! films work ok.. but they're mostly good for prototyping 'cause they're cheap.
4) buy 2 lpads. don't calculate static ones until you're SURE you're dead nuts.. its another calculation you're SURE to get wrong.. and it pays to mess around to verify your calculations by ear.
don't let yourself get discouraged.. horns really are a tough nut to crack-- but being diligent pays off in spades!
best of luck!
d
Hi
I second what you've said. I cross my 2441s in at 800Hz. If I move to a four way system (with a 2123 covering the mids) I would actually cross the 2441s in at 1.2kHz.
I spent ages (not quite two years!) tweaking my horns as well. They now sound superb, but the slightest deviation from the levels and XO points I now use results in a massive degradation of the sound.
I have no experience with first order passive XOs as I use 2nd order PPLXOs which I am ecstatic about.
Cheers. Doug
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