Finally we mounted the 2418 on a P-Audio PH-230. Here it is compared to the 2418 mounted to a SF-95.
Finally we mounted the 2418 on a P-Audio PH-230. Here it is compared to the 2418 mounted to a SF-95.
Kind of hard to make any definitive conclusions. It would seem that the PT-F1010 was the best CD horn of this bunch in that it had the smoothest downward slope. It is too bad that it doesn't allow for a crossover below about 1.2KHz. I suppose we should have compared it to the H9800 just for grins. I hope this data helps others on their audio journeys.
Widget
Thank you so much Zilch and Widget
I've a question regarding post #9:
Does it mean that the 2431 is
5 dB more sensitive than the 2426 and
3 dB more sensitive thean the LE85 ?
Yes, in this comparison. Thanks for pointing that out, I meant to address it but forgot. I believe the drivers are all inherantly very similar in their sensitivity, but for us to compare these three drivers on the PT-F1010, both of the 1" drivers required adapters. I believe these adapters are responsible for the lower output as well as the undulating response seen in the Blue and Green plots. I assume that due to the physical offset of the LE85 vs. the 2426, it's sensitivity was less affected.Originally Posted by Guido
Fun Day
Looks like you guys had a fun day.
Thanks for sharing.
I've often wondered how the 1" Bi-Radial horn on the larger SVAs would fare in such a comparison.
Out.
This is a very enlightening thread, thank you both for your time and for sharing the info.
Here's my commentary, while the work is still fresh. We haven't sorted it all out yet, but there were some surprises:
Post #2: The size of the back cap is not the big deal with respect to low-end response we thought it was, at least insofar as frequency response is concerned. Whether the smaller-can 2431 and 2435 sound any good below 1 kHz is another matter. On an appropriate horn, they'll at least play down there.
Post #3: Driven by 2431H, the performance of PT-F rectangular and PT-H square waveguides is virtually identical. PT-H plays a little lower, perhaps; it'd take a statistical study to distinguish them, most likely.
Post #4: We don't find a HF extension performance advantage with Be diaphragm (and $1000 premium cost) 2435HPL. As suspected, one of them is defective. They're both going back to JBL for warranty repair.
Post #5: Confirms my feeling that JBL is making design and/or manufacturing improvements on 2431H. Performance above 12 kHz appears "chaotic," but they all play similarly there on RTA. Newer ones are better in HF extension. About 15 dB of compensation is required to make them flat to 20 kHz on PT-F waveguides.
Post #6: For those desiring a narrow sound field, PT-F64 may be the ticket. Remarkably flat up to ~9 kHz, they play lower, too.
Post #7: The "economy" Ti-diaphragm 90° X 50° combo, it sounds good with proper compensation, actually. PT-H95 is available for 1.5" exit drivers, but the PT-F version of this "preferred" pattern is only prototypes thus far, alas.
Post #8: Hmmmm. Gonna have to see if it sounds better, too. Another economy alternative, though I'd want to support the much heavier 2426 driver independently. That is one cheap horn, for certain. There's also a SRX 90° X 50° horn for 1.5" drivers that might be worth looking at:
http://www.jblproservice.com/pdf/SRX...es/SRX712M.pdf.
Post #9: We think the adapter is responsible for the bumps in the FR. Actually, two adapters are required to mate the LE85 with PT waveguides. Still, as you may know, it's my favorite-sounding combo of "vintage" drivers. I play it with 3110A crossover for compensation.
Post #10: PH-230 is P-Audio's inexpensive 2342 clone. It'd take polar studies to determine if it's worth a whit for constant directivity. The real thing is still available, tho....
Do you think the larger backcap will make the difference when some real world power tests are made?. (My) Not having much knowledge of these types of tests (the ones you've already run), is it your experience, that a driver can exhibit an ability to play below it's FS ( 900hz- 2435HPL) and still perform with good, usable output, in a real world installation, crossed over below it's recommended 1.1k?. In other words, are the people that own 2435HPL's to assume that it is okay to cross them over at 800hz?
Interesting questions... we should have run an impedance sweep on the 2435HPL and 435Be with both the large horn and one of Zilch's smaller horns.
Zilch, if you bring driver #6 back over here we could run that test as well as run the distortion test.
Widget
I'm compiling a new measurement list.
I want to try 2431H and 2435HPL on H9800, as well, now.
And 2431H on PT-F with our crossover for it.
We also have a 2430H on the way for evaluation.
Note to readers: We have a JBL UHF driver study on the docket here, too - 2402, 2403, 2404H, 2404H-1, and 2405....
True. I'd like to point out that one of Zilch's goals is to find a combo that will eliminate the need for a tweeter. I am not sure if any of these combos are a stand out in that regard.
I would say that looking over these plots the most expensive drivers, the 435Be, and the 2435HPL have the most linear output through most of their range. This to me is significantly more important than extension, but all of these components are only parts of a system. It is up to us as designers to determine how best to use their capabilities.
If I were going to pursue a project with any of these combos, I'd take these plots into consideration but I'd make my final determination based on a series of subjective listening evaluations.
Widget
Aha! I wondered if that was in the back of someone's mind.
Out.
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