Problems bi-amping 4430’s with 5235 Xover

[Tony]

Well my initial problem was definitely the speaker internal/crossover switch. (That is after I sorted out my initial, initial problem of getting the interconnects made up with the somewhat unusual XLR connections.) Having oscillated the switch vigorously and getting the soundstage to balance correctly, after a couple of days it began to slew to the left again - more oscillation of the switch has corrected, but I suspect only temporarily; I shall need to get someone in to take it apart and clean properly or even hard-wire.

Ian, the massive ring at 1 kHz, is that with passive crossover, or, with an active crossover not having the LF levelling that jblbgw_man refers?

4313B is there a link to crossover detail for the 4430/4435 as per your recent comment? I have searched but have not come across it, just numerous references. It would be great if all this information on the 4430/4435 could be collated. I see someone else has today opened a new thread concerning active crossovers under the DIY Forum so this subject is certainly topical.

My OPA627 opamps arrived today, so that I can commence the 5235 upgrades as per jblbgw_man but it will be a little while as I have other bits to gather, and I do not trust my competency to do the work myself.

[Ian Mackenzie]

The mass control ring is located within the voice coil former.

[hjames]

4313B is there a link to crossover detail for the 4430/4435 as per your recent comment? I have searched but have not come across it, just numerous references. It would be great if all this information on the 4430/4435 could be collated. I see someone else has today opened a new thread concerning active crossovers under the DIY Forum so this subject is certainly topical.

My OAP627 opamps arrived today, so that I can commence the 5235 upgrades as per jblbgw_man but it will be a little while as I have other bits to gather, and I do not trust my competency to do the work myself.

JBL Pro website has info on the 4430/35 at -
http://www.jblpro.com/pub/obsolete/443035.pdf

also Techbot's links ...

http://www.jblproservice.com/pdf/Stu...ies/4430LR.pdf
and
http://www.jblproservice.com/pdf/Stu...ies/4435LR.pdf

and these more detailed sketches ...
http://www.jblproservice.com/pdf/Net...%20Network.pdf
and
http://www.jblproservice.com/pdf/Net...%20Network.pdf


Hopefully some of this will help ...
Good luck with your project!

[Tony]

The mass control ring is located within the voice coil former.

I guess I have shown my ignorance

[jblbgw_man]

I guess I have shown my ignorance

NO you haven't at all Tony , it's all a learning experience. Personally I have found the 4430/4435 the most difficult system to balance when bi amping, (and I have had 4430 since the 80's and built 2 sets) but when right it amazes me in it's performance. I believe it's a fine line between getting it right and getting it wrong, The clarity still leaves me breathless and it's totally neutral colouration (is that an oxymoron), the 2425 takes on a whole new personality when bi amped. I came from a Tannoy dual concentric background and I feel that "time alignment" is paramount .... and find the "combing effect" from multiple transducers difficult to tollerate now, others probably disagree but....... One thing for sure and that is there is a truck load of experience on here My next upgrade will be the cc dedicated bi amp xover network for the 4435's and I hope this brings substantial benifits ... no doubt I will post my results on here .

[Tony]

As often follows moments of I see that I am promoted from Junior Member to Member

I too have found the 4430 tricky to dial-in even before bi-amping when running passive; getting the speaker position right when what seems the slightest of movements can make pronounced differences and just mico-adjustments to toe-in, in particular, having a big effect on the soundstage. Difficult manouvering the 127lb each of each 4430 - must be even worse with a 4435!

I also (seem to ) think that the system altogether gets better all on its own for a day or two when I stop fiddling with it and leave it to settle - I leave my equipment 'on' all the time.

Last night I made a big improvement; I removed the glass-topped coffee table from in front of the listening chair (I know, I know better) and that cleared things up a bit - only trouble is where to put my beer-mug;
I guess I will have to drink it!.

[Tony]

I’m in NY now, but next week I’ll be back home.
I still have my 5235, no…. to be honest, I have two of them. Yes, because it has been my first experience with electronic crossover and was so excited that I found a second one for cheap and bought it as a spare…..this was quite long time ago. Then I found out that the passive crossover sounded better than active with 5235 (stock one, not modded…) and start changing electronic xo until I ended with the XVR1.
I can try to run some test and compare the 4430 driven with it (the 5235) and with the XVR1.
Just for fun.

If this can help….
Michele[/quote]

Michele, This would be very interesting

[screw_squirrel]

Hi everybody,

I am new in this forum and i have 2 questions about how to bi-amp the 4430.
1-) I know that the dedicated crossover is the 5235 or 5234A with the correct card (1KHz, 12dB slope) but is it possible to use the JBL M552 or any other 24 dB slope crossover to do the job?
2-) i have a McIntosh 2255 amplifier right now. What other amplifier should i take if i want to bi-amp the 4430? An other MC2255? Or can i make another choice in term of brand...?
Thank you all.
Eric

[4313B]

I posted the voltage drives years ago. If you duplicate the voltage drives you can use anything you want including building your own. The high pass is a simple 6 dB/octave circuit and you can make it either active or line level passive if you want. It works in conjunction with the 20 uF series capacitor inside the stock network to form the proper 12 dB/octave voltage drive. You have to keep that 20 uF series capacitor in there so you might as well bias it to make it sound better.

If you just slap any old 12 dB/octave 1 kHz active filter between the 2235H and the 2344A/2425H you probably won't like it. JBL put time and effort into creating the proper voltage drive for those specific components to cross over correctly at that specific frequency.

Once again, I am so angry that all the DX-1's were destroyed because they would make fantastic active networks for systems like the 4430 and 4435. The jackass(es) responsible deserve a sound beating, no pun intended.