On the original adapter these holes are centered between the adapter/horns holes:Originally Posted by 4313B
http://reconingspeakers.com/product/...lange-5026224/
Whereas on Robert's adapter these holes are partly behind them, and the 114mm ones are centered.
Based on your jiggling experience, do you think this would be more difficult in that case?
That is the one I am worried about: is 1" a good fit?
How deep is the thread on the 476?
I guess I will have to measure my 2450SL...
Hi POS,
It seems to me that the "interconnection plate" holes for 2450-1.5 [2450SL] or 2452, or 2431/35 drivers (positioned at 82.5.mm diameter) have to be offset-ed 67.5 degs (not 45 deg as shown), so a kind of nut can be mounted, not to be "covered" by the M2 horn mounting plastic stubs.. I think that 4313B has done in that way while using 476 driver.
regards
ivica
Deal all,
-No need to worry.
The studs I use are 27-28mm, a tad longer than an inch. I use them for 2450SL, 2451 and some other stuff I have lying around. One inch is probably as good even if a few extra threads won’t hurt. I bought a ¼” threaded rod and just saw the studs in the length I needed. -Cheap and effective.
The drawing is correct. The yellow holes are for mounting the adapter to the waveguide. The blue are for the large JBL bolt circle and the green for the small. As you can see all the JBL driver mount holes are geometrically in between the yellow holes so no waveguide boss should be in the way for mounting the nut on the studs from the driver. We have mounted both 2450SL’s (small circle) and 2451’s (large circle) on the adapter without any problem. If you start moving the holes you will wind up with some holes being covered by the bolts mounting the adapter plate to the waveguide. -Your call.
POS, I have no idea what the extra boss (9th) in the M2 waveguide is for. Maybe 4313b knows? It is not the same height as the other 8 mounting bosses so it cannot be used for mounting the adapter plate without milling to accommodate the extra height. Maybe JBL used it as a guide to get the adapter in the right place if mounting the driver in the cabinet after the waveguide was attached to the cabinet. –Just a guess.
I just forgot it in my drawing and initially planned to take it out but since I was unclear to its purpose I let it stay and made an additional hole in the adapter plate afterwards. I cannot see a need for it so on the rests of the waveguides coming in next week I will remove it.
Kind regards
//RoB
The solution to the problem changes the problem.
-And always remember that all of your equipment was made by the lowest bidder
Hi RoB,
As I have seen from Your figure green and yellow holes are "on the same radius", so after mounting the plate plastic horn studs would make a kind of difficulties to instal the nuts on the metal studs that were previously screwd into the driver body, so that is why I have suggested to make holes for the metal studs on 67.5 degs.
Unfortunately I have no M2 horn to confirm all that.
regards
Ivica
Hi Ivica,
If you look at the right hand side of my ugly drawing you will see that the diameter is different for all circles. As the nuts will have to be mounted from the side once the adapter plate is attached to the waveguide and the driver is inserted into the adapter plate, the important issue is that nothing obscures the driver bolts from the side. –And with the suggested adapter it does not for any of the two bolt patterns. Both 4-bolt JBL patterns are 90 degrees split and drilled so the small circle goes geometrically in between 4 of the waveguide studs and the large bolt pattern in between the other 4. Please see the picture above.
Kind regards
//RoB
The solution to the problem changes the problem.
-And always remember that all of your equipment was made by the lowest bidder
Ok, that makes sense, thanks.
While I am ordering on mcmaster.com, wouldn't one of these make the job easier than a hex nut, together with the 1" stud?
http://www.mcmaster.com/#thumb-screw-nuts/=x2x9v0
Hi,
Your call. Mounting with studs and nuts as described is really not any problem at all. It takes 2-4 minutes to bolt up any driver in a safe way.
Kind regards
//RoB
The solution to the problem changes the problem.
-And always remember that all of your equipment was made by the lowest bidder
HI RoB,
It is clear to me that the diameters of the circles are different, I want to say that the it would be better that relative angular positions of the for 2450sl stubs relative to the M2 horn stubs would be almost as the case for 2451
You have show on the:
http://www.audioheritage.org/vbullet...1&d=1429641211
But as I have said , I have no M2 horn to confirm that.
regards
ivica
I just measured my drivers:
- the 2450SL has a 16mm long thread (0.63")
- the 2435HPL has a 7mm long thread (0.28")
Robert's plate is 5.5mm thick (0.22")
So, when used with a standard 7/32" nut (0.22"), the ideal stud would be 27mm long for the 2450SL, and 18mm long for the 2435HPL.
So 1" studs for the 2450SL and 3/4" studs for the 2435HPL would be good matches.
Thin 5/32" nuts would be the perfect match with the 1" stud for the 2450SL
Dear all,
Sorry for the confusion on my adapter drawing. I uploaded an older design and failed to recognize that, hence the argue that it was correct. Sorry.
Of course members Ivica and POS was right the whole time!
The first set (pictures above) of adapter plates was drilled with the old design but the other sets used the design below.
Please see the correct drawing below. Sorry, my bad.
Kind regards
//RoB
The solution to the problem changes the problem.
-And always remember that all of your equipment was made by the lowest bidder
Hi Robert,
Thanks again for your work on these, and sorry to kinda hijack your nice project thread with general M2 waveguide discussions...
Why not make the adapter 5mm instead of 5.5mm to avoid having a 0.5mm gap between the driver and the horn?
I understand that this gap is partially filled with the compressed gasket, but still wouldn't it be better if not gap existed at all, and the gasket would be homogeneously compressed on the plate and horn?
Do we have a Euro price for the M2 waveguides or is pay once in the US inc shipping, then again with 20% VAT and once more with customs import duty?
Hi POS,
Agreed. However in reality there is no visible "gap", please see attached picture. Maybe my "0,5mm" really is less.
I did not want to take a chance that the driver would damage the "snout" when the bolts are drawn. In the best of worlds they would be completely flush mount when the driver is mounted and the bolts tightened and that seems to be the case from what I can see.
I paid USD on order and actually picked up the first set in the US and brought home. Talk to Randall at SE.com.
4313b, have you any chance to measure your fantastic 476Mg on the M2 waveguide?
Kind regards
//RoB
The solution to the problem changes the problem.
-And always remember that all of your equipment was made by the lowest bidder
Hi RoB,
That would be interesting to be seen, especially if off-axis measurements can be done too.
regards
ivica
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