Excellent.
Ian
Excellent.
Ian
It needs to be a bit more open-ended.Originally Posted by Guido
Seems XoverPro is a nice toy
Yup, the topology is rigidly structured.
It'll let me do notch filters now, but it won't let me plug them in.
[Don't need 'em, tho, looks like....]
It's only by chance I was able to get it to accept the AM circuit in the EQ section.
Surprisingly affordable ($62.87 retail) cast aluminum 2332 "Optimized Aperture" 90° x 40° horn is the same size as PT-F (12" x 6.5"). 2431H driver bolts on directly using the smaller diameter set of bolt holes provided in the flange. 1.5" throat entry rapidly constricts to now familiar racetrack oval.
[That sharp edge there can't be right, can it?]
2332/2431H performance on N3134 (4430), 3110A (wrong impedance), and "AM" crossovers. HF extension is clearly there in all cases, though there's something anomalous going on between 10 and 14 kHz. Nothing untoward in the impedance sweep.
Looks like original AM HF boost components may be better suited to this horn. For now, we KNOW how to make them listenable (bottom).
[Sounds good, actually....]
Followup: Tracking down the "problem."
See the DMS-1 Tech Note, which discusses the 2332:
http://www.jblpro.com/pub/technote/tn_v3n01.pdf
Most notably, in Fig. 10, vertical beamwidth doubles briefly above 10 kHz, no doubt with concomitant drop in SPL.
Fig. 11 shows active compensation voltage drive to "fix" it. After the boost, 18-20 kHz is actually attenuated for flat response.
"No compression driver system made by anyone can produce equivalent output levels with as low distortion."
That's with 2450SL-A driver. I wonder how these measure distortion-wise with 2431 and 2435 drivers....
[Interesting discussion of 4430 design philosophy there, too....]
OK, it looks like you have every (or just about!) flavor of horns for use with 1.5" exit drivers. Can you tell us which you prefer, and in what order? Thanks!
Actually, I have one more coming in, the 90° x 50° SR horn used in SRX-700. Supposedly they shipped this week. [Yeah, yeah....]
I also want to try a couple of crossover tweaks with 2332's this weekend; I'm presently listening to them using digital EQ, and probably not getting the best performance out of them as consequence.
I'd like to get others' opinions on them, as well. Several forum members are likely coming by in the next few days. The differences are subtle; we're well past 2370A vs. 2344A now.
At this point, it's more about soundfield patterns than anything else, after optimizing the crossovers for each horn variant. 243x seems to work well on any of them, at least above 1 kHz. These are competent drivers; we've tested them to death here....
In case you haven't discovered this already, being metal the 2332 will ring like a bell if you just set it on top of your speakers and play it. I mount it in an open backed box, and use a layer of putty to damp it. This makes an audible difference.
They're certainly "crispy" I'll say. Kinda like them, actually.
Don't know why it's so damn tough modeling a crossover for them, tho. They're virtually flat from 1.05 kHz to 8 kHz (+/- 1.8 dB); then they go all kinkoid. Maybe there's a reason JBL only used them with active EQ.
Only about 12 dB total compensation is required, but I note JBL's disclaimer when using their analog controller: "... additional system equalization may be necessary to fine tune the systems to the desired room response curve." Quite apparently so....
[Need better tools here, maybe....]
For those interested in the frustrating details of this process:
1) Voltage drive required for DMS-1, 2450SL-A on 2332 horn (right).
2) What I've got so far for 2431H on 2332 horn (red).
If I could get it more nearly level between 1 kHz and 8 kHz, I'd be done with it.
Boosting in the crossover region with digital EQ is a bad deal; it forces the 2235H woofers to play more where they don't like to and sound bad....
Hi Zilch!
Why messing around with those DMS Horns? Just for fun?
HEY, Guido!
Just tryin' 1.5" 90° x 40° - 50° alternatives while we wait for JBL to get around to making PT-F95, part #338650-001, which, unlike the previously presumed unavailable PT-H1010, really ISN'T available, since JBL has apparently never produced it.
While they're a departure from the 4430's 100° x 100° pattern, we assume there are some advantages in minimizing early reflectons off the floor and ceiling.
My own designs incorporate sloped baffles, like L200, to keep the cabinet height down. It's no coincidence that everybody tilts their "lowboys" up or mounts them up on stands. But, with constant directivity, that pushes the ceiling reflections closer as well. I THINK I hear a difference in clarity between PT-H95 and PT-H1010 used that way, even with 10' ceilings here.
The concept of interchanging horns to vary the sound field was appealing. However, it's now clear that each pattern within the same waveguide family requires a different crossover filter. It makes sense, of course, as each concentrates the available acoustic energy differently throughout the spectrum. Just didn't think about it until it smacked me. I'm gonna have to commit here soon.
Then, there's the whole "ambience" debate.
[Send me prototype PT-F95's please, JBL! I'll work 'em over for ya....]
Zilch,
Even cone based systems have varying Di versus frequency but this hardly gets a mention.
Perhaps the noteably issue is the soft/hard edge of various horn types / geometry.
Again, those reflections can be good or bad depends on taste and the speaker location choices in the room.
Frankly I have come to like the directed sound of the 43XX, others prefer the 100 x 100 thing......but are voices really 10 foot square? Nup.(in a highly reflective room)
If on the other hand my room was totally dead i might prefer the 100 x 100 thingy.
Ian
90° x 60° (50°) SRX horns for 1.5" exit drivers are 0.5" taller than PT-F's. In many respects, they're more similar to 2332's:
2431H's bolt directly on, but through the face of the horn. HUH?
- They're cast aluminum, and ring like bell.
- They play with a pleasant "crispness."
- They require a filter similar to 2332.
No throat constrictions involved, they just pour straight on.
RTA shows performance on AM crossover. They're flatter off-axis; the HF peak diminshes....
Seek filter intelligence here: http://www.jblproservice.com/pdf/SRX...es/SRX712M.pdf
ACK! Four notch filters. Maybe I just use AutoEQ....
[I think these are in Bo's new monitors, well appreciated by the Angelz....]
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