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JM Acoustic omni spheres
Old 30th April 2021
  #1
JM Acoustic omni spheres

Hi all,

I purchased a pair of these for my KM183 pair:

https://www.shapeways.com/product/ZS...-40mm-diameter

They came today, the fit is firm but not overly so, easy to get on and off, and keep in place where you would want them. Weight is very similar to the Schoeps-brand 40mm balls I use.

I haven’t had a chance yet to plug them in and listen, but will hopefully have a chance to do that soon!

I’m attaching some photos, as they look much better in real life than on the site.
Attached Thumbnails
JM Acoustic omni spheres-911c83bb-7c18-47c3-b137-e2d20c3ecab8.jpg   JM Acoustic omni spheres-cbe6d534-d5bb-4421-a3f0-1c6965bbd897.jpg  
Old 30th April 2021
  #2
Lives for gear
 
celticrogues's Avatar
 
🎧 15 years
Very cool! Looking forward to hearing your impressions of the sound.

Do they have a softer, rubbery texture, or are they hard plastic?

Thanks!
-Mike
Old 30th April 2021 | Show parent
  #3
Quote:
Originally Posted by celticrogues ➡️
Very cool! Looking forward to hearing your impressions of the sound.

Do they have a softer, rubbery texture, or are they hard plastic?

Thanks!
-Mike
Hard to the touch, and light, like the Schoeps branded balls, not heavy and rubbery like the DPA’s. I’ve never used a real Neumann SBK so can’t compare to those.
Old 30th April 2021 | Show parent
  #4
Lives for gear
 
🎧 10 years
Quote:
Originally Posted by king2070lplaya ➡️
Hard to the touch, and light, like the Schoeps branded balls, not heavy and rubbery like the DPA’s. I’ve never used a real Neumann SBK so can’t compare to those.
I wonder if the outer surface could be made more scratch resistant by coating it with a hard enamel or varnish...like the tough clear coating applied to timber floors ? You'd have to ensure the coating didn't carry solvents which could attack and soften the surface of the sphere !

Pool/billiard ball hardness would be the desired outcome...but light reflection off a gloss finish might trouble video cameras ?

Last edited by studer58; 30th April 2021 at 02:24 PM..
Old 30th April 2021 | Show parent
  #5
0VU
Gear Addict
 
🎧 15 years
Quote:
Originally Posted by king2070lplaya ➡️
Hard to the touch, and light, like the Schoeps branded balls, not heavy and rubbery like the DPA’s. I’ve never used a real Neumann SBK so can’t compare to those.
Neumann SBKs are like the Schoeps KAs in smoothness but more like the weight of the DPAs. They're hard and comparatively heavy, with a smooth surface but without the Nextel coating found on the Schoeps. At least mine are but they might've changed since I got them.
Old 30th April 2021
  #6
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fred2bern's Avatar
 
🎧 5 years
One Neumann SBK130 is 28 gr.
Old 30th April 2021
  #7
Lives for gear
 
Matt Nolan's Avatar
 
🎧 5 years
Castors, lathe, drill bits, boring bar...

A less expensive solution for less expensive mics!

If you really wanted billiard ball hardness, you could start with a phenolic composite ball.
Attached Thumbnails
JM Acoustic omni spheres-ape_balls.jpg  
Old 30th April 2021 | Show parent
  #8
Quote:
Originally Posted by Matt Nolan ➡️
Castors, lathe, drill bits, boring bar...

A less expensive solution for less expensive mics!

If you really wanted billiard ball hardness, you could start with a phenolic composite ball.
Where do you get all those tools for less than $80?!
Old 1st May 2021 | Show parent
  #9
Lives for gear
 
Matt Nolan's Avatar
 
🎧 5 years
Quote:
Originally Posted by king2070lplaya ➡️
Where do you get all those tools for less than $80?!
I was fortunate enough to already have the tools. The castors were about $15 for four.

Edit: and you could do a good enough job with a pillar drill and the right sized "flat" wood drill bit. Lots of people either have something like that or know somebody who does.

Last edited by Matt Nolan; 1st May 2021 at 01:30 AM.. Reason: added an afterthought
Old 1st May 2021
  #10
Lives for gear
 
🎧 10 years
Quote:
Originally Posted by king2070lplaya ➡️
......the fit is firm but not overly so, easy to get on and off, and keep in place where you would want them....
When it comes to DIY spheres, this is the part that's hard to get right....
Old 1st May 2021 | Show parent
  #11
Lives for gear
 
MandoBastardo's Avatar
 
🎧 10 years
Quote:
Originally Posted by studer58 ➡️
When it comes to DIY spheres, this is the part that's hard to get right....
True, but if you have a 2nd tube of crazy glue handy it's easier.

I like Scott's frozen toy store rubber ball DIY spheres method. Very chic and complex, but cheap: mics for grand piano? ~$4K budget
Old 4 weeks ago
  #12
Gear Nut
 
You're gonna wanna use a Forstner bit on those, not flat wood bit.
Old 3 weeks ago
  #13
Lives for gear
 
mpdonahue's Avatar
Quote:
Originally Posted by king2070lplaya ➡️
Hi all,

I purchased a pair of these for my KM183 pair:

https://www.shapeways.com/product/ZS...-40mm-diameter

They came today, the fit is firm but not overly so, easy to get on and off, and keep in place where you would want them. Weight is very similar to the Schoeps-brand 40mm balls I use.

I haven’t had a chance yet to plug them in and listen, but will hopefully have a chance to do that soon!

I’m attaching some photos, as they look much better in real life than on the site.
Do these have an O-ring or just friction fit?
Old 3 weeks ago
  #14
It’s just friction, I’ve attached a photo.
Attached Thumbnails
JM Acoustic omni spheres-1f650ed3-fc27-4221-a964-9ebf29a8cfe4.jpg  
Old 3 weeks ago
  #15
Gear Nut
 
I went the route Josephson originally did: hardwood balls from the craft store, with Forstner bit. Used a bit just larger than my capsules and made up the diff with wraps of masking tape - not only fills the gap, but provides just enough 'give' for a secure friction fit. Will need replacing after a few years as the tape shrinks, but not a big headache. Have also done some with plexi; a bit trickier but doable. Not noticed any difference in sound.

Important to ape (pun intended) the directionality and response curve of the M50, is to use capsules with a HF lift that begins about 1/2 octave below the end of the bump show in the DPA graphs for the 40mm APE. Comparing that graph with the M50's response curve, you can see that the very top of the M50's response is all capsule lift, the sphere no longer contributing. Using a flat response capsule will require use of the 50mm APE to extend the 'bump' all the way to the top, but that comes along with the bump beginning at a much lower fr. To my ears it results in a too-pushy upper midrange, so I stopped using that combo.
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