DIY 4430 the Beginning

[Guido]

How does it sound compared to your ole SENTRYs??

Let me know when will be the test party

And don't forget the lake party at friday

[Ralf]

Originally posted by Guido
How does it sound compared to your ole SENTRYs??

Let me know when will be the test party

And don't forget the lake party at friday

Hi Guido,

no test bevore all is ready...I will first finish the second one AND the four 18"...I have also to motify the 5235. One 2245H is not reconed yet, the 15" of the 4430 are Alnico Versions. I have to recone the both 2225 to 2235H, so we can compare Ferrit to Alnico. At sunday I got the PAS audio 4002 PCA from Harry (2,4 kW...) Tests are possible now, if I will be ready at all...

Lake party? Nobody has told me :-(
Why you organize parties generally on fridays? I will be in Hamburg on friday. Don`t know if I will be here at the right time...
mmmh...we could take the 4430 and test it at the party...I could bring my little generator and a small coice of my equipment...mybe

Ralf

[Ralf]

Hier are the first two of the four 2245 compined with the 4430...4430 fullrange driven by a Crest CA6, 2245 cutoff 80Hz 18dB driven by a 2,4 kW PAS audio...the sound is abnormal...earthquake feeling...

[Zilch]

JBL recommends inverting 4430's when they are positioned high like that.

Yes, the whole thing....

[johnaec]

Beautiful!

John

[Audiobeer]

Nice Job!!!! :giant woody: Drooling mouth;

[Ralf]

Originally posted by Zilch
JBL recommends inverting 4430's when they are positioned high like that.

Yes, the whole thing....

Hi Zilch,

you mean I should turn around the 4430 180 degrees? Then the 2235 is too far away from the 2245. ??? It could be better if I try the horizontal position for the 4430 (90 degrees), but 180 degrees?
mmh....can you explain these?

[Zilch]

Originally posted by Ralf
You mean I should turn around the 4430 180 degrees?

See the 4430 brochure, where:

"JBL has paid considerable attention to both the off-axis response and the total power response, and the network optimizes these parameters. While the response is smooth at all angles, the flattest response is, by design, on axis and above. This offers a greater number of listening positions when the system is mounted at or below ear level; for mounting above ear level, the system can be inverted to offer the same advantages."

http://www.lansingheritage.org/html/...84-4430-35.htm

You can see it in the published curves there.

If I were mounting them horizontal, I'd rotate the horns 90 degrees. I've seen it but never done it. I don't know what problems that creates with the mounting screw holes.

Whether having the woofers separated by inversion creates any problems, I don't know. Somebody else is gonna have to advise you on that. Remember that the 2235 in the 4430 carriers substantial program material up to 1000 Hz....

I have no clue why I remember this stuff, either.

[sanpablo]

I will build one 4430.

Before starting, I would like to know how you replaced R201 L-pad 30O 25W

In France, it's impossible to find this JBL genuine part. Deutschland or USA ?

You replaced it by what?

Have you a plan of your final crossover ?

Thanks

[Zilch]

http://audioheritage.org/vbulletin/s...ead.php?t=5209

See edited post in red on the last page. I ended up using the series section of a conventional L-Pad which varies from 0 to 8 ohms, where all the action is on the HF. Use a 16-Ohm L-Pad if you want more attenuation, but 8 is enough.

Using the parts specified, both controls set to "0" for flat response.

Being in Europe, you can probably get the proper Jantzen 0.04 mH inductor, L1, and avoid using the low value resistor in series with it. The Jantzen part number is #1318, 0.047 mH, 0.17 ohms. Unwind to 0.04 mH.

Guido & Ralf gonna have to tell you the specifics of this particular project. Reading it again, it looks like they used a 5235 active crossover in the system as well....

[Guido]

It's simply a variable resistor. One with 22 Ohms will do and they are available.

Check my email to you!

[Earl K]

- Don't you guys just run these pots wide open for "todays" music ?

- Do you ever attenuate UHF / for "yesterdays' musical styles" ( pre 70s' ) ?

- Anyways / both Zilches' & Guidos' suggestions have lots of merit .

- For those who like to live on the wild side ( & experiment a bit on the cheap ) /
Heres' a link for what I think should be a pair of decent standins
( Assuming an approximate maximum attenuation of only 20%, the power handling of this part should not be an issue ) .

[Earl K]

- To help your search, here's an Ohmite cut-sheet for their wirewound rheostats .

- If buying new, I'd be considering their 25W , 25 or 35 ohm versions ( as closest to original spec. ).

- Here's a link to a local ( Canadian ) supplier to give you an idea of what you are after & what you should pay new ( if in North America ) .

[Zilch]

- Don't you guys just run these pots wide open for "todays" music?

Basically, yes. It's sittin' at about 2 ohms most of the time. Once set for the room, I rarely mess with it.

That's why I suggest that 8 ohms is plenty....