Tomorrow I'm back home and then I will assist. Let's go for it
Tomorrow I'm back home and then I will assist. Let's go for it
Yup. Order up some drivers and horns, too. Let me know if you still can't get them. Sim is one thing, actual gear, quite another.Originally Posted by Guido
Let's go for it
YUM! Tasty....
Hi Zilch ( et al)
I'm all "eyes and ears" with this thread . Sometime in the future I may need to invest in a quantity of 3" diaphragm drivers. So your work ( and Widgets ) on measuring the 2431h is much appreciated by myself .
FWIW ; as a matter of comparison, I'd love to see its' response measured when used as a direct "swapin" on a H9800 / with the "tweaked for 435Be" network .
Personally, I wish JBL would offer a Titanium diaphragmed version of this 3" driver with the "aquaplas dusted" option . ( Just wishing )
Feel free to contribute your expertise at any time.
For example, how important is it that we maintain the 4430's 15-1/2" center distance between 2235H woofer and whatever mid/high compression driver/horn we end up using?
This is achievable in L200 using either the OASR horn or rectangular PT waveguide, but not the larger square PT waveguide, the P-Audio horn, or the 2344(A).
And to where on the drivers do we measure to get the time alignment right? See the driver pic here:
http://audioheritage.org/vbulletin/s...age=12&p=44254
We're dealing with major differences in horn/driver assembly depth....
Auditioned dbx DriveRack PA and Behringer UltraCurve DEQ2496 today.
DriveRack PA, $499, a better, more comprehensive unit including crossovers, but the tiny screen is impossible to read; no option to connect to laptop for reasonable viewing. Not intuitive, either. Pass.
UltraCurve DEQ2496, $299 on sale at Guitar Center. None in stock, except the one in their demo rack "never even plugged in." $285 with NIB $70 ECM8000 testing mic and free input, output, and 20' mic cables. Surprisingly, sales person actually knew what it was.
SOLD to the Zilchster. Thank you Leon!
[Enough $$$ left over to buy cat food, urgently on the list....]
- I always "time-align" when biamping, by utilizing a crossover that has a delay on the woofer section ( since the horns' diaphragm is just about always behind the woofers voice coil ) . I use 3 sinewave tones ( generated by a Behringer 8024 , plus some pink noise ) to look for the "best fit" ( with the 8024 acting as an RTA ) while I adjust the delay function of the crossover. As such, I really am completely ignorant of whether or not I'm electronically re-aligning the physical displacement of the two voice-coils - or - re-aligning 2 displaced acoustic centers ( not necessarily the same thing & therefore not really repeatable with a tape-measure and marking tape ). If I was you, I'd hang out as much as possible with Mr. Widget and try to get him to solve this question ( is it voice-coils or acoustic centers that are being re-aligned ? ) He now has the necessary gear to answer this question.And to where on the drivers do we measure to get the time alignment right? See the driver pic here:
I've got the Driverack 260 - the step up from the PA/Studio. 'Far more comprehensive options than the PA/Studio, and 'can also be controlled via laptop. I think it's intuitive once you get through the initial setup, but I think all these processors could be more so...
John
Its a bit of a riddle. I you don't have access to time alignment tools and there is significant difference in path length then in theory moving the horn away from the woofer will reduce the angle of the off axis lob around the crossover region. However the distance b/n the drivers spacing is best kept under D= wave length at the crossover point.
In the case of the 4430 I think they got it was close as practical and designed in 15 degree vertical upward polar title for inverted mounted.
I found that moving the horn in the horizontal and vertical domain effected the crossover transition amplitude response but this could also be tweaked wit adjustment of the C values on the woofer or horn.
Ian
I THOUGHT it was simple triangulation....
Gotta read between the lines of the hype to figure out what's actually going on.
Behringer UltraCurve does its AEQ (auto-equalization) thing. System F (2431H's on PT Waveguides, 4430 crossovers at max boost,) gets "room correction" (-1 dB/octave) option enabled for the garage. Once it's finished, I find myself boosting the bass further, 'cause I been listening to SUB1500 too long. B380's take it in stride.
U/C "begs off" Auto EQ below 100 Hz, anyway, (though you can force it to do it,) "because it is this range that may produce inaccuracies during the calculation of the frequency response, which might impair the result achieved with the AUTO EQ." Fine. I do it myself.
I was concerned initially that pink noise might only be available in the AEQ function, but it can also be manually engaged from the I/O menu with just two clicks. Now I have to figure out how to do each channel individually, if possible. Response varies substantially depending on mic position when both speakers are playing noise, probably due to phase cancellations.
Most correction occurred at 8 kHz, as predicted, where U/C attenuated -3.5 dB. Giskard's info regarding similar design 2435 may apply to these drivers as well; they don't start rolling off until after 7 kHz, maybe, so standard compression driver compensation below that overdoes it.
As hoped, U/C allows reading the actual correction in each band via moveable cursor, but the resolution is only two digits. We'll term it "ballpark." More than that, we'd need a significant sample of drivers for it to be meaningful, anyway.
Again, it's clear we're good at least to 20 kHz, maybe beyond, with this driver/horn combination.
UltraCurve Pro DEQ2496 is a way fun deal. You can watch and hear it do its correction as it's happening. And watching the RTA with program material playing is better than most TV.
[Gotta figure out how to more competently photograph it, tho....]
Yellow = 4430 set to 0
Green = 4435 set to 0
Blue = AM6212_00
Easy to see that the area around 7 kHz (b) is EQed out in the AM network.
(a) = crossover frequency at 1 kHz
"Once it's finished, I find myself boosting the bass further, 'cause I been listening to SUB1500 too long. B380's take it in stride.
Neat Huh!!! That auto EQ can work real well. I do the same I have my subwoofer levels up to give me a rising response from say 40/50hz down. Sounds like it's missing something if it's totally flat. I take my photo's using on a tripod. Using my hands is hit or miss. Attached are both channels driven with the 4435 crossover using 2344's with 2416's You can see the roll off very easilly. There is some microphone roll off but it primarilly at 20K. Your driver and horn combo looks better up high.
Rob
Auto EQ ??
HE! Let's do it old school
Guido: Auto EQ (SO cool!) is telling us what the passive has to do with these drivers, and it's saying the same thing as your curves, some reassurance that what we've learned so far is not a random anomaly. We'll confirm that with actual measurements of the drivers themselves. My next step will be to try with the AM 6212/00 crossover topology.
Got parts ordered? This a a Global Village endeavor!
Rob: Thanks for the tripod tip. Yup, "hit or miss" is what I get here.
It DOES look like this horn/driver combination is a significant step up, but you might want to wait until there's been more than just me listening to it, as itza $1000 (list) upgrade. We've gotta measure distortion in the HF region, too. It may be that we're pushin' it too hard up there.
What's the vertical scale on your RTA shown?
"What's the vertical scale on your RTA shown?"
Mines set at 1dB per tick. What can you do on the 2496?? The 8024 only gives you 2 choices .5 and 1dB. I would have liked a selectable scale more like Widgets RTA. What does the EQ curve look like??
Rob
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