Constructed at Giskard's suggestion with these parts:
Using breadboarding methodology dormant with the Zilchster for 35 years, simple crossovers yield surprising results with 2427H's on 2344A Biradial horns. 7-Ohm resistors are in series with L2 to comprise the requisite 7.5 Ohms. Boards are 5" X 6".
The sound? Clean, balanced, "sibilent." These are keepers:
2.2 uF caps were out of stock; results above substituting 2.0 uF, which may account for valley at 1.6 kHz.
Performance of HF section:
1) 2427H on 2344A Biradial.
2) 2418H-1 on PTH Waveguide (alas, no 2342 here....)
3) LE85 on PTH Waveguide, wrong impedance.
[Again wishin' I had 8-Ohm aluminum diaphragms for LE85's....]
Where's the CD compensation and HF boost comin' from?
These are simple 2-Pole, 12 dB topology, no?
What woof came with these? (B380's playin' above.)
Interestingly, RTA said invert the HF phase....
"Where's the CD compensation and HF boost comin' from?"
The 2.2 uF high pass is a simple single pole filter with the opposite roll-off of the Horn/CD. Think about that for a moment.
"These are simple 2-Pole, 12 dB topology, no?"
2-pole LP and 1-pole HP
Pull the 1.0 mH 7.5 ohm conjugate and run your plot again. See what frequency range that conjugate is affecting.
"What woof came with these?"
120T3
"which may account for valley at 1.6 kHz"
Probably a different resonance peak. You will need to run an impedance curve of your current horn/cd and then run an impedance curve of the stock 2416H/2342H combination for comparison. Adjust the 1.0 mH 7.5 ohm conjugate accordingly.
Added L200T3 voltage drive with 8 ohm loads (04-10-2005, 12:40 AM):
CAUTION: schematic erroneously has 2 L1's. I renumbered the one in HP (1.0 mH) to L2 for clarity.
Gonna have to think about Giskard's response here. Itza conjugate.
Ah-HA! 2.2 uF with 8 Ohms is 9 kHz, about. With 20 Ohms in parallel with the HF driver, it's more like 5.7 Ohms impedance, so the rolloff frequency is even higher. 7.5 Ohms in series with L2 makes it a conjugate, not a pole. I'm startin' to get it....
"20 Ohms makes it more like 5.7 Ohms impedance"
Yeah, impedance curves are your friend. It'd be nice to see some for all of these horn/CD combos you are doing.
I'm also looking forward to impedance curves of all those ring radiators you guys are going to run plots of...
Post all the data files if you wouldn't mind. They should be simple comma or tab separated values text files that other forum members can pull into the software of their choice.
In any case - Thanks for this R&D thread!
I hope other forum members see the value because there is quite a bit here.
It's mostly good fun, actually!Originally Posted by Giskard
In any case - Thanks for this R&D thread!
I hope other forum members see the value because there is quite a bit here.
[Never thought I'd be itching from drillin' fiberglass breadboards again, tho....]
Thank you for your informative contributions and guidance here!
Yep, 2416 has resonance peak at 1,4 kHz, 2426 at 1,1 kHz. I'll dig my impedance curves out.
Adjust the parallel resistance accordingly
Hi
- Question has been moved here.
Ok, whatever.
That's possible to a degree. One would have to run impedance curves of the 8 ohm and 16 ohm versions and then run an impedance curve of the 16 ohm version with the parallel resistance. Compare the results.
1) With HF conjugate
2) Conjugate disabled
It's working at 15 - 20 kHz looks like, doin' the HF boost?
Maybe some action down at 1 KHz, as well.
[Very clevah....]
The relevance is that for $72.76 a pair and a couple of hours breadboarding time, these little crossovers are credible performers with the "Quick & Dirty" combo using 2344A horns on 2426H. They'll likely work even better than I have demonstrated with the proper 2.2 uF caps in there, and with Guido's impedance curves, we may be able to "tweak" them a little more.
Apparently, they'll work for 4425 clones as well, using 2342 horns and the smaller 241XH drivers. Sounds like RobH's maybe gonna try that....
That'd knock the HF output down 3 dB, no?
Then I'd have to biamp them to get it back.
[Separate LF & HF inputs shown in pic above (bottom, outputs top) allow for that, tho....]
Doubling C3 and maybe adjusting the conjugate would be a better answer to using a 16 Ohm HF driver with them?
It would be nice to measure the stock L200T horn/CD.
Here's what the conjugate is doing with a 2425H/2344A:
Rob gonna do that, I betcha....
Hmmmm. No action above 10 kHz?
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