4430-4435 Revisited- A short story

[Ian Mackenzie]

This thread is not a hack work or a diy attempt at re-engineering an already splendid design but a look at what may provide more listening pleasure.

In a sense the 4430-4435 appears a more simple concept, but beneath that simplicity lies a very sophisticated and elaborate design.

Go here for details:

http://www.audioheritage.org/html/pr...bl/4430-35.htm

So we are not going to mess around with the design but look at the more subtle and perhaps the not so obvious. As the saying goes, if it it ain't broke don't fix it.

Reading over a few posts by members who have bi amped the 4430-4435 it would seem that while they felt there were some gains they also felt that something was lost.

As discussed here:

http://www.audioheritage.org/vbullet...4430+crossover


I also found this when biamping the 4344-4345 and the findings can be read elsewhere in the 4343-4344 upgrade thread.

Its a case of not what you are doing but how you do it. The 4430-35 has stood the test of time but with the associated equipment things have moved on a bit.

The intention is to build a purpose built active crossover and amplifier and arrange for a member to trial it for a time and post their observations.

If you are interested post or send me a pm.

Ian

[yggdrasil]

You are so full of energy.

[frank23]

such a good idea!

but I don't even have the time / energy to build cabinets for the 2235's I have had lying around [freshly reconed] for the past 3 years so I would not be worthy of such an effort to be made

it would be very nice to have a good active compensation setup for the 2344 as the active compensation in the M552 crossover is not good at all, not even for the 238x series for which it was meant

frank

[Ian Mackenzie]

Frank,

The 4430-35 has the compensation built into the passive crossover.

The compensation remains in the circuit when bi amping.

You are correct that other compensations may not be correct.

If you search the forums there are several threads that discuss the 4430-35 crossover in detail..incl voltage drives.

Actually....I have an idea.

My brother has a spare pair of 2235H's and I know where I might find the 2344 horns. I might build an exact 44430 clone over the holidays however i do not propose that this will become a diy 4430-35 thread.

Prior to my current system I spent 18 months testing & using the 2344 horn and it's passive crossover, so I have some idea of it characteristics. The important thing is not to mess with the JBL design.

Ian

[Zilch]

If we had the M552 crossover schematic, a simple mod to the "CD pre-emphasis" might make it play 2344 nicely.

[Think NL200t3....]

All I have is the block diagram in the manual....

[Ian Mackenzie]

Perhaps but that is not the intent here.

If one takes the time to read the profile and the White Paper it becomes obvious why they did what they did. No doubt there were other options but the one taken did everything they wanted to do at the time.

I will look at flattening the ripple (as discussed by David Smith) where possible at the lower end on the horns response.

I suspect you might have missed that with your rta .

[Robh3606]

The M552/553 are tailored for professional use. This includes the CD curves for the horn families. As far as the schematic you just have to know where to look.


http://www.jblproservice.com/pdf/M-S...onics/M552.pdf

http://www.jblproservice.com/pdf/M-S...onics/M553.pdf



Rob

[Zilch]

Thanks, Rob.

I'll scoot on over there now....

HEY! There's that donut power thingy I was talkin' bout....

[morbo!]

HEY! There's that donut power thingy I was talkin' bout....

lololol

i now will officially call it the donut power thingy from this day forth

[Ian Mackenzie]

For technical reasons boosting the driver HF response is inappropriate and has undesireable trade offs.

Please read:


"This thread is not a hack work or a diy attempt at re-engineering an already splendid design but a look at what may provide more listening pleasure.

In a sense the 4430-4435 appears a more simple concept, but beneath that simplicity lies a very sophisticated and elaborate design.

So we are not going to mess around with the design but look at the more subtle and perhaps the not so obvious. As the saying goes, if it it ain't broke don't fix it. "

The forums are full of hair brain modifications, I do not propose to involve myself in that pointless pursuit. Besides I think it only adds insult to injury of the original designer..David Smith

I will be working on this below the line from this point.

Ian

[Zilch]

I also read:

"Its a case of not what you are doing but how you do it. The 4430-35 has stood the test of time but with the associated equipment things have moved on a bit.

The intention is to build a purpose built active crossover and amplifier and arrange for a member to trial it for a time and post their observations."



As one who has tried both active and passive 4430 crossovers per JBL specifications, and also having built N3134 from scratch, there is likely no more stalwart proponent of the original design here than myself.

Frank mentioned M552. I said I'd look, with an idea in mind. If anything comes of it, we'll report it elsewhere.

I'm NOT a subversive....

[Ian Mackenzie]

I also read:

"Its a case of not what you are doing but how you do it. The 4430-35 has stood the test of time but with the associated equipment things have moved on a bit.

The intention is to build a purpose built active crossover and amplifier and arrange for a member to trial it for a time and post their observations."



As one who has tried both active and passive 4430 crossovers per JBL specifications, and also having built N3134 from scratch, there is likely no more stalwart proponent of the original design here than myself.

Frank mentioned M552. I said I'd look, with an idea in mind. If anything comes of it, we'll report it elsewhere.

I'm NOT a subversive....

You really need to invest in a Clio or what ever over a simple RTA but I guess you know that already. Otherwise its snakes and ladders perpetually.

I saw an advert for a cheap Clio if you are interested.

[Earl K]

A solution for both was to use a series resonant bypass network.* 1 microfarad in series with about .08 milihenries would resonate around 15K and give about 2 dB more output for the highest frequencies.* It also gave a little less around 5k where the 2425/biradial combo was a little hot.* A variable resistor in series the resonant leg gave a nice “upper treble” adjustment so we now had a pair of controls with really useful control centers and range.

- I inquired about the inclusion of the series .02 mH inductor ages ago ( obviously the value was adjusted after the 7.5 ohm conjugate was added ). I felt the answer I received at the time didn't reflect its' true purpose . The above info vindicates that view .
- Is this UHF "resonance" part of the "magic" that people speak of when referring to this product ?
- This series resonant circuit approach (LCR ) was rarely implemented in other 2 way networks as a "UHF boost". Perhaps these other networks would benefit from the addition of this "magic" bullet.

<> EarlK

[Robh3606]

"Is this UHF "resonance" part of the "magic" that people speak of when referring to this product ?"

I a word no. At least not for me anyway. I have run the set-up using an outboard EQ to bring up the last octave and the results sounded the same. What makes the "magic" is how unhorn like the 2344 sounds. With a 1" dome up top you can get a very nice balance off axis. With most other horns the balance changes with the DI index. Listening to the 4344's you can easilly hear when you are out of the window. The XPL 200's the 2344 are more closely matched in this respect and the 2344 is actually better. That said if you want the most clarity and detail from 10K and up the XPL's and 4344 with the 077/2405 wins out. There may be some ripple lower in the passband, which honestly never bothered me, but the imaging and overall smoothness in the room more than makes up for any issues. IMHO

Rob

[BooBoo Magoo]

4430 and 4435 are sooooo last century!