Topic: Jecklin Question

[John Kelly]

So I think I'm gonna build myself a jecklin disk and use my omni's a lot more.  However I have these tiny Audix mics, I'd rather not have a gargantuan foam disk at the top of my stand.  So how small can I make it before it becomes useless?  Does it just have to be big enough to block the two mics fully? 

Any help would be greatly appreciated.

[Tim]

well technically a true jecklin disk is something like 12 inches in diamater. I believe Todd R has constructed one a bit smaller  though I think.

it should certainly be bigger than just the mic capsules but perhaps you can make it proportionally smaller

[vox humana]

The size of the disk has to do with the wave length for different sound frequencies, not the size of the mics. The smaller the disk, the higher the pitch where you lose stereo separation. The 12" diameter is about the smallest you can go and still have decent stereo separation at higher frequencies. I therefore wouldn't make it any smaller than 12". I use the Jaecklin disk with both Neumann KM100s and the Core Sound stealth mics with very good success. But it's not tiny!

[ShawnF]

Right--this is what I came across, also.  The one I described to John and posted pictures of in the Team Audix thread (http://taperssection.com/index.php?topic=19233.90) is less than a half centimeter off Jecklin's specs for size of disc and separation of mics (and distance from mic to surface).  I like it a lot, but it is bulky, no getting around it.  Not a problem for my applications, but I could see why there would be some reluctant to use it for more typical situations.  Didn't Moke make a mini baffled stereo disc, though?  I seem to recall reading that he was fairly pleased with it.  Or at least someone did in his Jecklin thread.  Here: http://taperssection.com/index.php?topic=800.30

Shawn

[John Kelly]

Great stuff Mike.  I think I'm going to shoot for 8 inches. I'll post some pics once I get everything done!

+Ts all around

[Tim]

good info, thanks a lot guys!

John if you're not using your omni's much you're going to be presently suprised...

honestly I could see a situation where my next rig just has only omni's, subcards, and figure 8's...  amazing sound from those patterns

[John Kelly]

backatcha John.

I've been looking for the right piece of foam to create a 7" disc, because I *think* that I like the isolation of a larger disc. I think you are right on with that size.
Have you seen the links, from other internet sources, in regards to building your own discs? they were posted in the j-disc thread. good stuff to grab some ideas from.

Think about building in as much adjustability as you can. Big differences in sound can be achieved by changing the width of the mics in relation to the closeness to the disc face.
Don't have your disc bearing the load of the mics, rather, have a t-bar device, and fit the disc to that.

good luck with a great technique!

Yeah I've seen a lot of that stuff.  I'm not sure about how to mount the mics, I mean they *are* pretty tiny, but I don't want to screw up the disc just to make mounting the mics easier.  I'm sure I'll figure something out.

[Todd R]

I made one that is 9"x8".  So far, I've only used it for one set, onstage.  Ran the second set DIN with cards, which I ended up liking better, since the chattiness of the club with the omnis was too much for my taste.  I'm looking forward to running this at some outdoor shows to really test it out.  I'm not convinced that j-disk omnis are that well suited to bar-scene taping, even if it is stage taping.

I thought the separation from mine was pretty good though, even though it is smaller than spec.  I imagine that having the mics closer in towards the disk compared to what the jecklin spec calls for (8.5cm?) would help if you make a j-disk that is smaller than 12 inches in diameter.  Once the summer outdoor season hits, I'm going to run mine a bit more and try out various spacings from the disk to see how that changes the sound.

There are pics and a description of what I did in the other thread on jecklin disks (or is it an omni mic thread?).