Topic: Jecklin disk with multipattern LDs

[ShawnF]

As the Jecklin fans are aware, the original specifications call for avoiding mics with switchable patterns:

"For recording with the Jecklin disc, sound pressure microphones must always be used; i.e., “real” sound pressure microphones. Microphones with a switchable directional characteristic, insofar as they are designed as double diaphragm microphones, may not be used."

I know this was brought up previously with regards to Schoeps MK5, but since it was reported that that particular mic, in omni mode, was a "real" sound pressure microphone with a single diaphragm, the question of the disk's use with a double diaphragm mic wasn't really addressed.  If it came up elsewhere, I haven't yet found it with the seach terms I've been using.

So, my question is, why?  I just picked up a pair of AT4050s, and I want to try them with a Jecklin setup (though they'll primarily be flanking split omnis for my MG200 main pair).  They are dual diaphragm, though I have no idea how this works and if both diaphragms are employed in the omni setting, or if it would be a similar situation to the MK5 (I'm assuming not).  Why would the design of this omni make it unsuitable for Jecklin use?  It may just be that my lacking of real understanding of how these multi-pattern mics work is missing something obvious, but when is an omni not an omni?

Regardless, I'm going to try it and see what happens (unless you tell me this will bring on the end times, or something).

Also, I haven't yet seen this document referenced here (sorry if it has been mentioned and I've missed it):
http://www.mdw.ac.at/I101/iea/tm/scripts/jecklin/tt03mikrofon.pdf#search=%22Jecklin-Scheibe%22

Near the end (p. 32) Jecklin has revised his specs for his technique, now suggesting a larger disk (35 cm diameter) and wider separation (36 cm).  The wider separation seems pretty substantial, since it's more than twice the original spec.  Not that most people feel bound to adhere to the specs precisely, of course, but still . . .

[Shawn]

I believe moke used a J-disc with ADK TLs frequently and was pleased with the results. This may be one of those cases where the exact specifications (for j-disc) don't need to be strictly followed.

[ShawnF]

Sorry--I should have made clear that I saw in my searching that others (Moke most especially, or at least most vocally ) had used this type of mic.  I was just wondering what the basis was for the exclusion of it in the original specs.

[Javier Cinakowski]

I tried my switchable LD's with a J-disc and liked the results.....  I too am interested in why the specifications frown upon this....

Grimace - 12/18/2006 - Walnut Grill - PGH, PA
Source: Studio Projects C3's>Oade p-mod UA5>iRiverH120
Lineage: iRiver>USB2.0>CEP2.0(normalize)>CDwave(track)>mp3(256kbps)
Notes: stage-lip j-disc

http://www.treespine.com/rig/rig_files/rec_000204.mp3

[ShawnF]

Interesting--thanks very much.

[kuuan]

Would SP-CMC4 with omni capsules be useable with a Jecklin Disc?

[audBall]

Would SP-CMC4 with omni capsules be useable with a Jecklin Disc?

Absolutely!   I've tried it with the at943's.  The bottom line is, you can use two tin cans if you so choose.

[Javier Cinakowski]

Would SP-CMC4 with omni capsules be useable with a Jecklin Disc?

Sure, I bought a set of U853 omni caps for this purpose....  I figure these mics, even though electret are more similar to jecklin requirement than the LD's...

[rowjimmy]

I was thinking of using my naiant msh-1o mics for a jecklin-disc setup...

[bdasilva]

Those are just (well not JUST) Panasonic capsules... They will work great.

[Jimna]

simplistic quasi-answer:

I think this has to do with the slight HF directionality offered by the single capsule pressure transducer omni vs. the dual membrane of the LD's. The dual membranes not exhibiting the same directionality.

Personally, I found no issues with the LD rear caps causing any cancellations or other issues when used with the baffle. I just "focused"/turned them inwards towards the disc face to cancel them out of the final sound, (not truly cancelling, but attenuating them).

so does this mean that you angled the front of the mics slightly away from the j-disc?  how much of an angle, moke?  also, what size j-disc have you used, and did you go by his specs for separation?  thanks for sharing moke.  +T

[RebelRebel]

something about the switchable LDs not being a "true" omni charactaristic, like Moke said. of course i use them at times..necessity is the mother of invention.

[Jimna]

hey moke,
i found this thread to very helpful, but the pics are not accessible anymore, are they still around?  (referring  to  page 2 where you show your step-by-step construction of the j-disc.)

the thread:http://taperssection.com/index.php/topic,800.15.html

thanks jim

[Jimna]

simplistic quasi-answer:

I think this has to do with the slight HF directionality offered by the single capsule pressure transducer omni vs. the dual membrane of the LD's. The dual membranes not exhibiting the same directionality.

Personally, I found no issues with the LD rear caps causing any cancellations or other issues when used with the baffle. I just "focused"/turned them inwards towards the disc face to cancel them out of the final sound, (not truly cancelling, but attenuating them).

so does this mean that you angled the front of the mics slightly away from the j-disc?  how much of an angle, moke?  also, what size j-disc have you used, and did you go by his specs for separation?  thanks for sharing moke.  +T

I pretty much stuck with the white paper OSS technique, with the major exception of using the LD's (which were all I had at that time).
OSS calls for the mics to be toed-out about 30º, which, with LD's, also turns the rear cap inward to the face.
I also found that I ran the mics closer together than the official technique. This evolved after many times of critical listening and comparison to recordings made in the same hall, with the same acoustic ensemble.

hey moke,
i found this thread to very helpful, but the pics are not accessible anymore, are they still around?  (referring  to  page 2 where you show your step-by-step construction of the j-disc.)

the thread:http://taperssection.com/index.php/topic,800.15.html

thanks jim

I mocked it up in plywood, and quickly realized that it was going to be too heavy. So, I finished it with styrofoam, rather than plywood.

how did the styrofoam hold together with the wood and the L bracket?  seems like it would pull apart from the weight of the wood and metal?.?.  did you just use the screws like w/ the plywood?

[Jimna]

i hit loew's & jo-ann fabric today.  the styrofoam is the hardest thing to find unless you buy a 8x10 sheet of house insulation(which wont fit in my vehicle).  otherwise all the craft places sell nothing big enough.  i got one piece extra, long cut off the extra and hot glued it on to get my15x15.  PITA, but still im on my way & i learned that hot glue is great to use with the styrofoam.  i think the hot glue will replace mokes pins for attaching the fleece.  i also picked up some fur for a set of dead rats while i was there.  moke thanks a million for letting me rip off your ideas.  you rock, +t 

ps. i also just finished spraying my spacer black to look professional in my new extended vert bar, another stolen idea of mokes.  i feel like im coping your homework.....from 5 yrs ago!

sorry to hijack the thread.