JBL D2430K mounting issues

[pos]

The version sold by speaker exchange *is* the M2 version, according to the serial number and specific sticker on the driver.

I don't see how the M2 adapter would not fit the D2430K.
That said I don't see how that adapter would be useful for anything else than mounting that driver to a M2 horn...

 

[weltersys]

Art, Many thanks for the offer. Unfortunately, although I'm logged in, I don't see any "PM" icon that I can use. Worse than that, I don't have access to a digital camera. All I can say is that the three horns I have all measure 3.5 inches between the centres of the mounting holes, whereas the D2 driver measures 3.5 inches between the far edges of the mounting holes and 3.25 inches/82.5 mm between the centres.

Simply highlight the name of the person you'd like to message, "private message" is the second option on the pull down menu.

For the difference of 3.25" to 3.5" on center, a few minutes of filing with a 1/4" rat tail file would get your horns to fit with the drivers, and eliminate the extra depth of an adapter.

I had to do the same on 1" to 2" adapters when mounting BMS 1" exit drivers for the
http://www.diyaudio.com/forums/multi-way/212240-high-frequency-compression-driver-evaluation.html

 

[weltersys]

Both version of the D2430K have the same bolt pattern (and should fit the M2 flange);
I got a pair of the M2 version from speaker exchange, and a total of 5 of the Vertec version off ebay.
Out of those 5 drivers only 2 measured good distortion wise, but I guess it was a problem with the history and abuse of these particular drivers, and not the Vertec version in general.
The two that measured good measured exactly like the M2 version distortion wise.
The response of the 7 drivers was essentially identical.

POS,

Surprising that (frequency?) response was essentially identical, while distortion varied- I'd be very interested to see the frequency and distortion responses of the various D2430K drivers you tested.
Did you try cleaning the gaps and centering the diaphragms on the 3 drivers with higher distortion?

Did you happen to compare the 2450 SL distortion to the D2430K ?

Art

 

[pos]

Art,

Here are some response comparison between the D2430K, 2435H and 2450SL-Be (truextent diaphragm). The lower trace is 3rd distortion. The 1/4" mic used here is pretty flat (forgot to load the calibration file, but it only has minor variations) and provide decent distortion measurement.
D2430K compression driver information? - Page 3

Here are some more precise distortion measurements done with a 1/2" mic.
Please disregard the response curve for that particular mic...
D2430K compression driver information? - Page 3

Now a "good" D2430K vs a "bad" one, meaqured with th 1/2" mic.
The response is not representative, and is smoothed, but you can see that both drivers are exactly superimposed here...
D2430K compression driver information? - Page 5

These D2430K came from ebay (2 were "bad", one was "good").
At the time I did not know if the 2nd order distortion peak around 1.5kHz was normal, but I recently measured the D2430K I got from speaker exchange (M2 version, NIB), and they measured like the "good" one from ebay both response and distortion-wise.
The peak around 1.5kHz is clearly there, and rises with level.

 

[pos]

Did you try cleaning the gaps and centering the diaphragms on the 3 drivers with higher distortion?

Forgot that one.
No I did not : the D2430K is not easy to disassemble as you have to remove the aluminium sticker on the back, and go through the complicated mounting method. I send back the defective units and I did not want to deal with that problem at the time.

I now have another pair of d2430k from ebay here, and the person that send them over to me for measurement did disassemble one of them to see how it looks like from the inside. It appears that this one now measures good whereas the other one does not, so there might be hope 🙂

 

[dr.joe]

Simply highlight the name of the person you'd like to message, "private message" is the second option on the pull down menu.

For the difference of 3.25" to 3.5" on center, a few minutes of filing with a 1/4" rat tail file would get your horns to fit with the drivers, and eliminate the extra depth of an adapter.

I had to do the same on 1" to 2" adapters when mounting BMS 1" exit drivers for the
http://www.diyaudio.com/forums/multi-way/212240-high-frequency-compression-driver-evaluation.html

Never thought of that! Will have a go. Well, actually I'll ask an experienced cabinetmaker I know to have a go! Many thanks, Joel.

 

[weltersys]

Art,

These D2430K came from ebay (2 were "bad", one was "good").
At the time I did not know if the 2nd order distortion peak around 1.5kHz was normal, but I recently measured the D2430K I got from speaker exchange (M2 version, NIB), and they measured like the "good" one from ebay both response and distortion-wise.
The peak around 1.5kHz is clearly there, and rises with level.

Pos,

I didn't see any drive level reference in your distortion measurements.

Have you done any D2430K measurements at near rated power?

Art

 

[pos]

No, my distortion measurements are only meant for driver to driver comparison at a given (moderate) SPL level.

 

[phase_accurate]

I ordered my D2s with the following horn. Apart from the availability issues for 1/4" screws in central Europe mounting was no problem. I did only have to sligthtly sand the mounting flanges because of that "dots" that remain from the injection moulding.

JBL Horn Lens #5006815 for STX825 - Speaker Exchange

This one here seems to be a nice 1.5" throat horn as well. But I don't know if the D2 can be mounted on that one.

JBL 352606-002 Horn Lens for SRX715, SRX722, SRX725 - Speaker Exchange

Regarding the difference between 2430 models for PA and M2: Aren't they the same but wired differently for both purposes ? I.e. the coils in series for the M2 (the driver comes actually delivered with a removable cable in place that connects the coils in series) making it a 32 Ohms driver and coils in parallel for the PA applications.

Regards

Charles

 

[dr.joe]

phase_accurate, Many thanks for the link to the STX825 horns! These also happen to cost the same—for the pair of horns with mounting plate—as a single D2 adapter plate.

As regards the difference between the PA and M2 versions of the D2430K, they both have that removable cable connecting the coils. At least my PA version does.

 

[Massilia]

Hello,

After reading this post, I would like to know if the JBL d2430k, M2 version (the one solded by The Speaker exchange), is fully compatible with 2431 or 2452 drivers (mounting holes diameter, bolt circle).
Or should I buy too the JBL M2 horn flange, to be used with a PT horn dedicated for the 2431.
I guess exit diameters are identicals?

Thanks in advance

Regards

 

[dr.joe]

The D2430K has a 3.25 inch bolt circle, a 1.5 inch exit, and uses 1/4-20 bolts. Should be easy enough to measure the 2431 and/or 2452 to determine if they have the same three parameters.

 

[JR_W]

That's what a 2452 and 2431 have, too. I think all of the 1.5" outlet snoutless pancake drivers except the 2451 share the same mounting dimensions.

 

[Massilia]

OK fine, thank you very much!

 

[phase_accurate]

For those who are interested in the performance of the D2430s on the cheap STX825 horns I made an informal measurement tonight. The response shown is on-axis. Driver laying on the floor, horn facing upwards (without any baffle). Measuring distance was 70 cm.
Below 4 kHz the difference between my two drivers (or maybe the horns or the driver/horn combinations) is between 0 and 0.5 dB. Response linearity below 5 kHz is +- 1dB (keep in mind that this is the raw response with an unbaffled horn !). Above 5 kHz it is a little more ragged and the "constant directivity drop" is slightly higher than I expected. But still excellent. And the measurements definitley confirm what my ears told me in November when I did some casual listening comparison: That it is inherently more linear "out of the box" than my old 2344/2426 combo.

Regards

Charles

 

[dr.joe]

I thought part of the advantage of the D2430K driver is that it doesn't require the heavy EQ in the higher frequencies that is typical of most "large format" compression drivers. The curves phase_accurate has kindly provided seem to show the same steep drop-off in the HF. Am I missing/misunderstanding something?

 

[Massilia]

Thank you phase-accurate. Excellent.
So I will replace my 2452s by a pair of d2430k, just have to wait for the availability at "The speaker exchange", end of february expected.

 

[phase_accurate]

How steep it drops does not only depend on the driver but on the horn as well. But it can easily be EQd flat until 20 kHz IMO.

Regards

Charles