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Author Topic: Capsule Height/Placement In Original U47 Headbasket  (Read 4323 times)

kidvybes

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Capsule Height/Placement In Original U47 Headbasket
« on: February 26, 2015, 10:26:07 pm »

...I attempted to research any info pertaining to the capsule height placement in the U47 and the fact that the upper headbasket frame dissects the capsule's exposure...some claim this was done to reduce plosives or sibilance...I assume it was intentional, but is there any specific explanation for this configuration?...any thoughts or historical reference would be greatly appreciated...
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klaus

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Re: Capsule Height/Placement In Original U47 Headbasket
« Reply #1 on: February 26, 2015, 11:39:55 pm »

I am wracking my brain right now: I just answered the same question somewhere but cannot find where...So here it goes again:

The U47 capsule mount is at the end of a stiff rubber column whose height and material properties need to be an ideal compromise between elasticity (shock absorption) and stiffness (preventing the capsule to whiplash against the inside of the head basket after a shock). Making it shorter gets you into the territory of the C12 and its capsule mount problem: heavy subsonic Trittschall-transmission. The whole thing transmits too much at 20 hz and below when triggered with even the smallest external excitement.

The secondary, and probably unintended (positive) consequence of the column length Neumann chose is this: the higher you place the capsule inside the basket, the father away it gets from two  parallel and reflective surfaces-the basket wall and the base plate-and the closer it gets to the domed (and diffractive) top.

Here is an experiment I have made a few times to understand the real-world consequences of an acoustical obstacle placed close to a diaphragm: mount the same CK12 capsule, once in a C12 (no obstacle in front of the front diaphragm) and then in a C24 (a nasty support bar crossing right through the middle of the front diaphragm): I cannot hear an difference.

That leads me to believe that the small circular weld connecting the U47's cylindrical basket with the domed portion of the basket must be quite negligible, acoustically.
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Klaus Heyne
German Masterworks®
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kidvybes

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Re: Capsule Height/Placement In Original U47 Headbasket
« Reply #2 on: February 27, 2015, 09:48:10 am »

So Klaus, you would say the height of the capsule's pedestal was intentional for acoustical purposes within the headbasket structure, but more than likely without particular concern for the proximity to the headbasket's frame support...I appreciate your time in re-addressing this issue...Thanks!
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klaus

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Re: Capsule Height/Placement In Original U47 Headbasket
« Reply #3 on: February 27, 2015, 12:00:06 pm »

It's all speculation (unless Uwe has access to prototype discussions from the late 1940s), but I speculate that the capsule's proximity to the support/weld was known, considered, and found to be not a fatal flaw for the overall head design.
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Klaus Heyne
German Masterworks®
www.GermanMasterworks.com

kidvybes

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Re: Capsule Height/Placement In Original U47 Headbasket
« Reply #4 on: February 27, 2015, 05:12:10 pm »

...very insightful and de-mystifying in terms of the lingering sibilance/plosives rumours...Thanks again, Klaus!
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Jim Williams

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Re: Capsule Height/Placement In Original U47 Headbasket
« Reply #5 on: February 28, 2015, 12:04:51 pm »

Quote
The Rode NT-2 base is rounded.
Can you explain "rounded"? Do you mean domed? Pictures?
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Jim Williams

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Re: Capsule Height/Placement In Original U47 Headbasket
« Reply #6 on: March 01, 2015, 12:46:15 pm »

Since the original post was deleted, I think I won't elaborate.
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klaus

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Re: Capsule Height/Placement In Original U47 Headbasket
« Reply #7 on: March 01, 2015, 05:46:37 pm »

Only two people can delete a post on this forum: you or me.
As I did not delete your post,  I am asking you to elaborate your comment.
Thanks,
KH
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Klaus Heyne
German Masterworks®
www.GermanMasterworks.com

turtlerock

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Re: Capsule Height/Placement In Original U47 Headbasket
« Reply #8 on: March 18, 2015, 10:04:55 pm »

just to add to the conversation with my favourite rare u47 picture   look at the Original u47 baskets !
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Rick O'Neil
turtlerockmastering.com

klaus

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Re: Capsule Height/Placement In Original U47 Headbasket
« Reply #9 on: March 18, 2015, 10:15:47 pm »

"Manufaktur" in the true sense of the word: made by hand.

Lower left picture shows the internal capsule-head divider screen, as used on U47 through 1952. A fine mesh screen separates the front area from the rear all around the capsule. I never understood its purpose and would not mind to get an education from someone who knows.

Keen observers will notice something else: The capsule lead-out wires are soldered in place AFTER the capsule is mounted. (To avoid excessive heat transfer to the membranes a soldering iron with an angled, extremely long tip is used.)

Why don't they avoid "accidents" and solder the wires to the head assembly, before they mount the capsule, and then simply screw the wire eyelet to the diaphragm centers? Because capacitance variations and slight diaphragm distortion may be introduced if the screw is undone after the capsule has been calibrated. Not messing with the screw's original torque  guarantees that the desired capsule specs remain intact (Neumann still does it that way- the wires on replacement capsules are already attached!) 
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Klaus Heyne
German Masterworks®
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turtlerock

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Re: Capsule Height/Placement In Original U47 Headbasket
« Reply #10 on: March 18, 2015, 10:23:34 pm »



I also like the different banded headshell shape that i have never seen , which would have run straight across the capsule .. clearly somebody thought better of it in  final production  .
 I believe this magazine article ran in  late 1949 ! 


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Rick O'Neil
turtlerockmastering.com
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