I acquired a (used) pair of D2430K compression drivers, curious to see how they'd perform on a few different 1.5 in. entrance horns I have on hand.
But once I got them, I found the mounting bolt pattern was different from any other driver I've encountered: the bolt circle appears to be 2.75 inches.
Are there adapters available to enable mounting the D2430K to "ordinary" 1.5 in. horns?
TIA, Joel.
But once I got them, I found the mounting bolt pattern was different from any other driver I've encountered: the bolt circle appears to be 2.75 inches.
Are there adapters available to enable mounting the D2430K to "ordinary" 1.5 in. horns?
TIA, Joel.
Joel,
Don't know the "ordinary" bolt circle of your horns.
I have some adapters that have the JBL standard 4" bolt circle and a 3.5" bolt circle, though the entrance is 1.4" and would require a bit of filing to go to 1.5".
Additional holes for the 2.75" circle could be drilled, though it may be less work to start from scratch with a some 1/4" aluminum plate.
The adapter plate could be unscrewed from the 2" exit portion pictured below.
For some reason "Upload of file failed" (repeatedly)..
Art
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Art,
Thanks for your comments. I'll investigate creating my own custom mounting plate, though given the information below, it may not be possible.
Fact is, I mis-remembered the bolt-circle measurement of the D2430K. Just re-measured: it's 3.375 inches, just a bit too small for the 3.5 inch bolt-circle measurement typical of 1.5 in. exit drivers.
I'm wondering if I somehow bought some weirdly defective drivers. . .
Thanks for your comments. I'll investigate creating my own custom mounting plate, though given the information below, it may not be possible.
Fact is, I mis-remembered the bolt-circle measurement of the D2430K. Just re-measured: it's 3.375 inches, just a bit too small for the 3.5 inch bolt-circle measurement typical of 1.5 in. exit drivers.
I'm wondering if I somehow bought some weirdly defective drivers. . .
Actually, mine are drilled just under 3.5", would be easy to file the difference out, and could sell for 1/2 what the above thread's plate goes for.
Still can't get anything to upload here today...
After some discussion with a supplier, I ordered a pair of these. They neither fit the driver properly, nor do the holes line up with any of the three 1.5" horns I have.
I assume this flange is intended only for mating the driver with the M2 horn.
I know they are designed for the M2 waveguide as they are used specifically in that design. very odd that they do not fit the D2430k properly...
post #964
D2.jpg Photo by 666csi | Photobucket
JBL Master Reference Monitor - Page 20
Modified adapter plate for use of JBL 2451 and/or 2452's(can't recall witch one at the moment, thought the OP specifies in the thread):
http://www.audioheritage.org/vbulletin/showthread.php?37127-Experiments-with-M2-horns/page6
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Neither (same routine used for hundreds of uploads), but it seems to be working today.
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Just got off the phone with The Speaker Exchange in Florida. The phone call was about returning the M2 horn flanges I recently purchased from them. What was interesting is that the fellow to whom I spoke said that, according to sources at JBL, there's two different versions of the D2430K driver, the "M2" version which sells for under $400 each, and the version used in the Vertec (?) PA speakers that costs around $1500.
He suggests that I probably have the Vertec version and that that's why the M2 horn flange doesn't work with it.
Unfortunately, though, he had no information on how the two versions of the D2430K differ. Matter of fact, he said the people to whom he spoke at JBL had no idea, either, just that there were two D2430K drivers for two different applications.
Anyone else heard of this oddity—two different drivers with the identical model number?
He suggests that I probably have the Vertec version and that that's why the M2 horn flange doesn't work with it.
Unfortunately, though, he had no information on how the two versions of the D2430K differ. Matter of fact, he said the people to whom he spoke at JBL had no idea, either, just that there were two D2430K drivers for two different applications.
Anyone else heard of this oddity—two different drivers with the identical model number?
What $1000++ is in Vertec version??..Makes no sense.
I have a pair of D2's that is not M2 labeled, so probably from Vertec. They use the standard 82,5mm bolt circle all the other modern large format JBL drivers use.
I have a pair of D2's that is not M2 labeled, so probably from Vertec. They use the standard 82,5mm bolt circle all the other modern large format JBL drivers use.
Yes, mine are also not M2 labelled and use the 82.5 mm bolt circle—exactly why it doesn't fit any of the 1.5 inch exit horns I have on hand, which all use the 3.5 in. bolt circle. . .
I also thought it bizarre that the SR version, rather than the monitoring version, is so much more expensive. But, again, Speaker Exchange had no details on the difference, if any, between the two drivers.
I also thought it bizarre that the SR version, rather than the monitoring version, is so much more expensive. But, again, Speaker Exchange had no details on the difference, if any, between the two drivers.
I suspect someone has this backwards.
I believe the M2 version is the $1500 version, at least that what I was quoted when I asked.
I researched this a bit, a while back.
Both are "D2430k" but the part numbers are different.
The M2 version has no replacement parts and I think it's a production unit tested and selected to meet tolerances required for the top-of-the-line top-dollar monitor.
The Vertec units have replacement dia's available, presumably wider tolerances and cheaper, for use in quantity in tour applications.
JBL used to use selected 2450 drivers in their previous monitor, was called a 2450SL IIRC.
So it's not unprecedented.
Best wishes
David
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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.
Last iterations of the DMS-1 had the 2450SL-A version, but there again it was just a different diaphragm (ribbed version with aquaplass)
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.
The 2450SL version is a 1.5" version of the 2450, similar to the 2451 but with the "mordern" bolt patter (same as the D2430K) and an aquaplassed diaphragm. No selection there AFAIK.
Last iterations of the DMS-1 had the 2450SL-A version, but there again it was just a different diaphragm (ribbed version with aquaplass)
David, your suggestion that the M2 version is the more expensive version of the D2430K certainly makes more sense than what The Speaker Exchange told me. They continue, however, to describe the cheaper one they're selling as the M2 version.
Now back to the task of finding or making an adapter so i can mount the driver on "regular" 1.5 in. horns that use a 3.5 in. bolt circle. . .
System215,
Did you see the adapters in post #9?
If you would send me a photo of your D2 and horn, both with a ruler across the bolt patterns and exit/entrance I could machine them to the exact dimensions.
PM if you are interested.
Art
The differences between the 2450 and 2450SL are even greater than just the diaphragm. The 2450 has a "snout", a short horn if you will, on the front of the driver. Similar to the older JBL compression drivers. The 2450SL is the snoutless "pancake" design, like the more modern compression drivers.
The mounting bolt pattern of the 2450SL and D2430K are the same.
Not my pics, just examples from the web:
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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. I have the M2 adapters from The Speaker Exchange, they don't really fit the driver, so I'll be sending them back.
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