D2430K compression driver information?

[Dave Zan]

Yes these come from ebay.

Lucky I did not bid and raise your cost. Must check here next time I want a pair.

I did not try the 8ohms setup, but I'd expect the measurements too look the same

I think there is a coupled mode that can exist when the VCs are in parallel, that does not exist for series connection.
Ideally the two sides are perfectly equal and there will be no excitation of that mode, the measurements will be the same.
I wondered about the difference in reality. Would be an informative test, if the results are the same then the driver is close to theory.

What amp...?

I plan a dedicated compression driver amp of ultra low noise.
Much better than a standard amp that has to be wastefully padded down
I have mentioned it a few times in DIYaudio, where I see some of your posts too.
Lower VC resistance alters some of the trade-offs in resistor noise, power loss in the feedback network etc.


Best wishes
David.

[pos]

4313b posted the M2 technical manual in another thread.

The manual clearly states there is no replacement diaphragm for the D2430K:

Driver, High Freq.
D2430K
(5032754X)
No Diaphragm Kit
Driver Only

This is quite choking for such an (apparently) fragile driver aimed at professional use.
One advantage of this technology over big Be (or Mg) diaphragms is obviously the cost of the diaphragms themselves, so if one cannot buy replacements this is getting a bit silly.

Then I checked the VTX25 tech manual, and it states the opposite:

Compression Driver (3)
D2430K
(446213-001X)
Diaph Repl
D32RD2430

The 32 ohms marking seems to indicate that the replacement kit is the pair of diaphragms, maybe already assembled as opposing rings?...
That would be logical as matching between the two diaphragms is critical (for distortion canceling), and sealing is also probably a big issue here.
Also interesting to note: the part list for the driver itself is different... (?!)

That said, I have had a pair of D2430K in my hands and to be honest I do not even see how one is supposed to open the damn thing to install new diaphragms...
Maybe under the foilcal, like the old ring radiators?

Would anyone have information (price?) on these replacement diaphragms?

[Mr. Widget]

)...I have had a pair of D2430K in my hands and to be honest I do not even see how one is supposed to open the damn thing to install new diaphragms...
Maybe under the foilcal, like the old ring radiators?

Would anyone have information (price?) on these replacement diaphragms?

I wouldn't sweat it... I doubt you would ever be able to buy replacement diaphragms.

The current direction JBL is going is free driver replacement while under warranty and buying a replacement driver after that until NLA... my real fear is that NLA may be sooner than would have been considered reasonable before everyone started sharpening their pencils scalpel sharp.


Widget

[JeffW]

JBL Pro took down their Transducer Parts List a while back, no more checking by the public to see if a replacement part is even produced anymore.

[pos]

Well, I think I'll stick with the good ol' 1.5"/4" compression drivers: they are easy to service, can perform admirably (especially with Be), and beside JBL there will always good diaphragms for these on the market for a reasonable price (Radian, Truextent, etc.).

[Dave Zan]

M2 technical manual ...clearly states there is no replacement diaphragm for the D2430K:
...
Then I checked the VTX25 tech manual, and it states the opposite:

...
The current direction... is free driver replacement while under warranty and buy... a replacement driver after that until NLA...

It seems JBL expects the M2 owners not to blow them, and if they do then to have the money to buy a complete replacement.
But PA/tour operators are expected to blow out drivers so can buy replacement parts,
That would almost make sense if the M2 driver is perhaps a selected/matched unit, perhaps why the different part number?
Or is it just an assumption that M2 owners can be squeezed harder?
A >$1000 driver that is a throw-away item would make me very reluctant to buy.

Best wishes
Dave

[pos]

That would almost make sense if the M2 driver is perhaps a selected/matched unit, perhaps why the different part number?

That is exactly what I was told today by KW55 (he also told me the M2 exceeded by far everything he had listen to in his showroom )

That makes sense indeed, as matching between rings and proper installation is probably paramount with this push/push distortion cancellation strategy.

[4313B]

It seems JBL expects the M2 owners not to blow them, and if they do then to have the money to buy a complete replacement.
But PA/tour operators are expected to blow out drivers so can buy replacement parts,
That would almost make sense if the M2 driver is perhaps a selected/matched unit, perhaps why the different part number?
Or is it just an assumption that M2 owners can be squeezed harder?
A >$1000 driver that is a throw-away item would make me very reluctant to buy.

Best wishes
Dave

The D2 is considered a replacement part rather than a finished good like other JBL compression drivers so it runs around $1.5k a pop instead of $2k a pop.

Harman has gone to a whole driver replacement strategy.

There were D2 replacement diaphragm kits, I would assume they are still available to JBL Pro Service Centers.

That is exactly what I was told today by KW55 (he also told me the M2 exceeded by far everything he had listen to in his showroom )

The performance of the M2 isn't trivial. JBL was not blowing smoke when they called it a game changer.

The only problem I have with the entire scenario is people having spent serious money on K2's and E2's... my very first reaction to the M2 was within the context of the K2 and E2. "Uh oh..."

[pos]

What about the "selected D2" scenario for the M2?
Have you heard anything along those lines?
That would explain the difference in part number between the VTX25 and M2 spec sheets.

[4313B]

That said, I have had a pair of D2430K in my hands

Can you please post an impedance curve of one with the resistor pad from the M2? (13 ohm series, 11 ohm parallel)

[pos]

Sorry, I did not run any impedance measurement on them, and I returned the pair to the seller (after having tried to replace just one, but the replacement I received also had "issues").
My conclusion is that those drivers are too fragile to be bought used, the faston terminals especially: gently pushing a terminal during measurement could change distortion figures by up to 20dB...

(lower traces are 3rd distortion)

Knowing that one cannot buy replacement diaphragms...
No thanks, not for me, not even new and enclosed in a speaker...

[ivica]

Sorry, I did not run any impedance measurement on them, and I returned the pair to the seller (after having tried to replace just one, but the replacement I received also had "issues").
My conclusion is that those drivers are too fragile to be bought used, the faston terminals especially: gently pushing a terminal during measurement could change distortion figures by up to 20dB...

(lower traces are 3rd distortion)

Knowing that one cannot buy replacement diaphragms...
No thanks, not for me, not even new and enclosed in a speaker...

Hi POS,

Thank You for the measurements You have done. I do not know what kind of horn You have used, but the response over 13-14 kHz is not promising too much. May be the driver was faulty...

Regards
Ivica

[pos]

Hi Ivica

Please disregard the amplitude response in this measurement: I use an uncalibrated 1/2" mic for distortion measurement (although I should calibrate it really...)

Measurements and comparisons using a much flatter 1/4" mic can be found here.

The three D2430K I measured had all pretty much the exact same amplitude response, faulty or not, with or without fiddling with the terminals...

[more10]

BMS now has a driver with dual diaphragms, the 4599ND

The BMS 4599ND dual diaphragm driver incorporates two identical 3.5” concentric annular ring diaphragms, connected to a common 2” throat, providing extremely high acoustical output.

It is available from USSpeaker. They have a version with aluminium demodulation rings, the 4599NDHE. There is no information from BMS on this driver yet.

[sguttag]

So has ANYONE found a difference between the VTX version of the D2 (product number D2430K) with a part number 446213-001X and the M2 version of the D2 (also product number D2430K) with a part number 5032754X?

I'm a cinema guy so my experience with the D2 is zero though at a friend's recommendation, I've begun a DYI M2 project (with matching SUB 18ish subs). I am a JBL certified reconer so I have access to parts and I can tell you that the 446213-001X is MUCH easier to lay one's hands on than the 5032754X. But the price is also MUCH higher.

The diaphragm kit, D32D2430K is very much available (in-stock in the USA, as of this writing) and reasonably priced, for what it/they is/are. I haven't changed one so don't ask what is involved (I've yet to have the driver in my hand).

Has anyone measured or worked with both? Are they just two different part numbers for the same piece? Is the M2 version somehow different?

-Steve