Buying a Jecklin disc but I don't want to get ripped off!!!

[Recording David]

I'm looking to buy a Jecklin disc but the few I've found seem to be mighty expensive! Any tips for finding one reasonably priced? Before anyone suggests it building it myself is not an option - I suck at that kind of thing.

Thanks guys thumbsup

[Petrus]

Maybe some handy friend of yours would be kind enough to help? I have made a couple, total cost maybe 10-15€ each + 2 hours of time.

[Corran]

I'm actually working on one right now with pieces available at craft stores and custom cut material. When everything is done I should be able to offer it to Remotesters for like $75 including shipping.

Would this interest you (or anyone else)? My prototype is almost done, I'm just sourcing materials for connecting it to a mic stand.

[boojum]

I built my disc out of an old Oral Roberts LP, some foam from a craft store and some faux lambs wool. I cannot sew, so I turned the fake lambs wool inside out after it had been cut, stapled the edges, and then turned it right side out and pulled it over the foam covered LP. Presto! Cost: ~$10. I drilled a hole at the edge and attached the disc to a mounting piece from a mic clip and was good to go. I use a mic bar and place the omni's behind with a 4" extender to get them to the right height.

If you do not want to be bothered there is the fellow who is making them. I am sure they are prettier than mine.

[Petrus]

OK, I refrained from telling how I did mine, but:

First I sourced a piece of 9mm plywood (from lumber store scrap bin, about 2€). Made a circular piece from it with a router. Glued a double ended screw about 1/3 from the edge for mic holders. At the bottom I cut a small notch and epoxied a Manfrotto bronze light stand spigot to it with two small squares of plywood. This spigot goes to a Manfrotto kneejoint which in turn fits any light/mic stand. With that the angle can be adusted freely.

The plywood disk is first covered with 15 cm diameter 12mm foam (discard from building sites, basically the same as cheap camping matress), on top of that full size layer of foam. This gives the center more thickness, looks nicer. Cheap scrap piece of fleece or fluffy fleece is then cut circular (2 pieces) and sawn together half way, turned inside out and wrapped around the contraption and sawn by hand the rest of the way.

[Ol' Betsey]

Originally Posted by boojum

I cannot sew, so I turned the fake lambs wool inside out after it had been cut, stapled the edges, and then turned it right side out and pulled it over the foam covered LP. Presto!

Classic!

R.

[Dale]

Originally Posted by Recording David

I'm looking to buy a Jecklin disc but the few I've found seem to be mighty expensive! Any tips for finding one reasonably priced? Before anyone suggests it building it myself is not an option - I suck at that kind of thing.

Thanks guys thumbsup

look under The Lazy Recording Rig
at this link < stichting klankschap >

[boojum]

Originally Posted by Dale

look under The Lazy Recording Rig
at this link < stichting klankschap >

Good link!

[Recording David]

Thanks for the tips guys - I'll have to see if I can find someone to make one for me! @Corran - yes, I would be interested in buying one of yours if you start a 'production run'.

[mathieujm]

This one is the "real" one.

I own it, but when I bought it, it was cheaper !

JMM

[John Willett]

Originally Posted by mathieujm

This one is the "real" one.

I own it, but when I bought it, it was cheaper !

Same here - this is also the one I use - but swapped the clips over so I could use my MKH 20s with it.

I also hope the get the Schneider disk (same but with a lump in the middle).

[John Willett]

Actually - as this thread reminded me - I have just rung Canford Audio about getting the Schneider Disk for myself.

Details on the Jecklin and Schneider disks are on the MB website HERE.

[mathieujm]

Originally Posted by John Willett

Actually - as this thread reminded me - I have just rung Canford Audio about getting the Schneider Disk for myself.

Details on the Jecklin and Schneider disks are on the MB website HERE.

Naturally, everybody knows the paper about how using OSS Jecklin disk ?
It's on the Josephson site. Search for the Tech Note 5

JMM

[Plush]

The Jecklin or Schneider disk is an engineered and patented product. It is probably best to just buy the real thing. That way you know that you have the dimensions and absorption coefficients correct.

For best results remember to use omnis with a tipped up treble response for baffled stereo work.

[Recording David]

Originally Posted by Plush

The Jecklin or Schneider disk is an engineered and patented product. It is probably best to just buy the real thing. That way you know that you have the dimensions and absorption coefficients correct.

For best results remember to use omnis with a tipped up treble response for baffled stereo work.

I didn't realise this - maybe I'll just bite the bullet and get it.

[Petrus]

If it is patented and the patent is still in effect (might not be, the invention is quite old), one is allowed to make them for own use, but not sell them.

So DIY is still a legal option.

[JEGG]

There have been a variety of different dimensions in use over the years. These can be found easily by searching.

A couple of things: "Diffuse" omni's are specified, but depending on everything (as with any other technique), this isn't necessary. The distinction among omni's with lifts is a bit vague anyway, and the whole thing about "diffuse omni's" was a product of a time period. Ditto the use with dual cardioids. Any mic and technique has to be adjusted for the room and the source, anyway.

A shuffling circuit was originally specified. That's done much easier and with greater flexability now that we have other means of processing. If you want to stay analogue you can always feed a MS matrix with an appropriately frequency specific signal, then mix back. It can be done much easier ITB. The use of a shuffler is hardly mentioned anymore, and most people don't use it.

If you make one: forget plywood: how much would a plywood disk weigh?

Here is what I recommend:

1. A craft store (such as the chain Michael's) often has foam discs in a wide variety of diameters. Get the appropriate one. They are also available in a variety of thicknesses. Paint all of the edges flat black just in case a bit of fabric doesn't mate perfectly.

2. Also at craft stores, there are two commonly stocked very thin felted wool fabrics. They are sold in squares that are about 8 or 10 or 12 inches on a side. They are black and do not reflect light. These have excellent non reflective characteristics for audio. Forget the lambs wool thing. How to test surfaces for good audio performance. Listen to a sound source and place one of your trial fabrics/mountings immediately behind your ear and at a right angle to your head or ear lobe. If there is a change in timbre, the surface is not suitable. If only a reduction in ambience is heard, that is a good surface. (There is a slight product difference between the adhesive and non adhesive backed product. The non adhesive product is better, but again, that's easily tested. The appearance of the felt is slightly different as well.)

3. Attach the felted wool to the surface with-surprise!!-glue.

4. There are a variety of ways of mounting microphones and discs. Using a regular ol' stereo bar, top the center mount with a cheap mic clip. You can regulate the orientation by putting a washer underneath the stereo bar (on a mic stand) and if needed a washer on top of the bar under the clip. The clip can hold the disk. You can also rotate the clip forward and downward for position as well. A little creativity will get your mics in the right position and distance on the side. If you're using real omnis-which is best-you do not need shock mounts. This will free you up to use different hardware to position your mics. You can also use some tinker toys from Sabrasom-very useful products! With various Sabrasom pieces, you can actually position a "spike" glued into the middle of the disc which is then attached to a little horizontal bar which you can custom order by length. This is the same octagonal rod that fits everything else Sabra makes.

This sort of approach results in a very lightweight product that has excellent cosmetic characteristics. The weight of the disk is a few ounces, at most.

You'll need some experience in placing the array. It's not quite like anything else.

Also, the array has a surprisingly good forward characteristic. The Jecklin disk arrangement has a slight "phase array" characteristic built in, whether by accident or not. But-again- the array does have a surprising forward reach.

Don't use the foam surfaces which are quite popular presently on commercially available disks. Foam surfaces reflect much too well.

Good luck.

[JEGG]

Originally Posted by Plush

T

For best results remember to use omnis with a tipped up treble response for baffled stereo work.

These days, that's pretty much dependant on the environment and source and the mic characteristic. A shuffler is specified as well, but few use it now. When I was experimenting with different disks, I was concerned that sources straight ahead of the array would sound dull, likewise those that were far to the left or right. The reality of the disk, though, results in a good forward reach-a lift is often not required-and the unique right to left frequency dependant separation also results in no lift being needed for extreme right or left, either. The polar response of the array is probably quite uneven in terms of frequency response, but it still works quite well. It would also have an equal but different uneveness with HF boosted mic's.

Again, this is completely dependant on all the variables involved in a given situation.

There was a time period when "diffuse omni's" became formulaic in a somewhat bizarre degree, as if it were some ultimate given truth. The disk idea was developed in that era. Now we have omnis in every HF flavor. Before, almost any omni had to be "diffuse" at the tip was exactly 6 dB no matter the diameter (and thus the polar pattern) of the diaphragm or what sort of sound was produced. In the heretical case of having a flat omni (which were pretty unusual when dedicated omnis began their collective life), the engineers were instructed to add exactly 6 dB at 10k, no matter what. They never specified the shape and extent of the rise. They did specify a shelving characteristic, but as you know, only the minority of omnis at the time had acoustical shelving, they were mostly peak, with a wide variety of location and slope of the peak. The peak was often greater than 6 dB.

Also, when many classic microphones and techniques were developed, the medium was completely different. People heard things on LP's, and analogue tape was around. This shaped many assumptions which remain today, even though the media has totally changed from recording to playback-no value judgement intended, just an observation.

[Corran]

I'd like to know if this is actually a "patented" item that I would be unable to sell. The one I'm designing will be all but identical to the one on Mercenary Audio's site, except for styrofoam rather than more flexible foam and a slightly different mic attachment system but same principle.

[audio ergo sum]

Originally Posted by JEGG

...In the heretical case of having a flat omni (which were pretty unusual when dedicated omnis began their collective life), the engineers were instructed to add exactly 6 dB at 10k, no matter what. They never specified the shape and extent of the rise. They did specify a shelving characteristic, but as you know, only the minority of omnis at the time had acoustical shelving, they were mostly peak, with a wide variety of location and slope of the peak. The peak was often greater than 6 dB.

...

Who is "they" ? Who instructed the engineers, no matter what?

[0VU]

Originally Posted by Recording David

I didn't realise this - maybe I'll just bite the bullet and get it.

If you just want to try it out, rather than buy one, PM me. I could probably lend you one for a while, so you can decide whether or not it'd be something on which you want to spend the cash. I've got two of the MB disks (as sold by Canford) and one of the MB Schneider disks. I also have a few other disks; some based upon Jecklin's newer suggested dimensions and some based upon my own (and other people's) messing around.

I did a lot of experiments with baffled pairs whilst at university, using a very cumbersome experimental setup which put me off thinking of using them in the real world until I was introduced to the much more elegant and simple construction of the MB disk in the early 1990s whilst working alongside some DRS engineers on a load of concert recordings/broadcasts in Switzerland.

Having listened to, liked, and used their OSS disk pair, on arrival back in the UK, I ordered a couple of MB Jecklin disks and used them pretty heavily for broadcast and CD work for many years - everything from solo instrumental recitals and chamber ensembles up to large scale orchestra/choir/soloist extravaganzas! At one point it reached the stage where people I knew/worked with regularly would see the disk at concerts or on sessions and seek out the recording room/truck to say hello, assuming that the disk meant that I'd be at the other end of the wires! I realised I really was getting too predictable when a speaker at an AES UK lecture on mic techniques referred to the Jecklin OSS disk, saying that it may be an unfamiliar sight to many present but they'd "almost certainly heard it if they listened to [a radio station which was a major client of mine], as their engineer uses it most of the time".

I still use them quite frequently but not as often as I used to, as I'm playing around with a couple of other things a bit more. They're often talked about, especially over here (UK) as something that's inflexible and only really useful for large scale work in big halls/live acoustics or as an 'effect/ambience' pair but I'd seriously dispute that; I find them as flexible/inflexible as any other mic technique. Their suitability in a given setup depends upon the same variables of performance, acoustics, personal/client preferences as any other method of recording and, like other techniques, they have their own foibles, characteristic strengths and failings which will rule them in/out in different circumstances. I'd be as happy to use a disc on a solo recital/string quartet as on Mahler 8, if it gives me the results I'm looking for/being paid to get. Like most other things in recording there's no right/wrong; keep an open mind and see what works for you/your clients.

Now that I rarely need to have two disk rigs out at the same time (and I have more disks anyway), I could certainly spare one if you'd like to check it out before shelling out for one of your own.

[Plush]

A really good discussion here and thank you to 0VU who has made a great post.

My comments earlier were aimed at encouraging the user to buy and examine a real Jecklin or Schneider disk. It is made with foam of a certain density and composition.
The inventor specified foam as the disk's material.
This is the "engineered" part of the build of the disk.

Those proposing to make a disk of styrofoam, for example, are on the totally wrong path. It might work, but it is surely going to turn out to be tonally improper.

I do not know if the Jecklin or Schneider disks are still under patent. That was not really my main point.

For posters like JEGG who have good experience building disks, I can certainly say that you have more experience in building them than I do.

On the matter of which omni to use, I'm sure that EQ'ing a flat omni will work in the disk as well. I don't buy the notion that anyone was "taught" to be a robot and add any EQ to omnis. What I can buy is that some engineers were told to add high freq. EQ to flat omnis if they sounded dull in the hall. (But that is separate from any Jecklin disk useage---the technique is not widely embraced.)

Likewise I do not buy the notion (above stated as fact) that off axis response is ragged or unpredictable. It is predictable across a wide variety of quality omni mics.

Experimenters and home builders/craftsman should be encouraged. However, before you build your own, check out the real thing and hold it in your hands.

I have tended to use the Schneider disk on smaller fixed ensembles. By fixed I mean groups sitting in one position. (string quartets, brass ensembles, piano quartets)

[John Willett]

I ordered my Schneider disk from Canford Audio today.

Actually, someone else is ordering one as well.

Canford are placing the order on the manufacturers today - so if anyone in the UK wants a Schneider or Jecklin disk, now is the time to place the order if you want it quick.

[Recording David]

Originally Posted by 0VU

If you just want to try it out, rather than buy one, PM me. I could probably lend you one for a while, so you can decide whether or not it'd be something on which you want to spend the cash.

This is a very kind and generous offer! Check your PMs.

Thank you 0VU thumbsup

[John Willett]

Originally Posted by Recording David

This is a very kind and generous offer! Check your PMs.

Thank you 0VU thumbsup

Where abouts in the UK are you David?

I am actually round the corner from 0VU.

[Recording David]

John, I'm in Bedford.

[John Willett]

Originally Posted by Recording David

John, I'm in Bedford.

Not that far then - I'm near J9 of the M40.

[mathieujm]

Originally Posted by John Willett

I ordered my Schneider disk from Canford Audio today.

Actually, someone else is ordering one as well.

Canford are placing the order on the manufacturers today - so if anyone in the UK wants a Schneider or Jecklin disk, now is the time to place the order if you want it quick.

Hi John,

Some news about using the Schneider disk ?

JMM

[John Willett]

Originally Posted by mathieujm

Some news about using the Schneider disk ?

Not used it for music yet.

I *did* use it for a special audio art project recording speech.

This was performed in late May as part of the Battersea Arts Festival.

2 x Neumann KM 183-D - I had a couple of Neutrik straight-through XLR male to female adaptors to make them longer (from Canford Audio) so they would clip into the disk properly and have the capsule at the correct point (otherwise the clip would be on the XLR connector).

It works extremely well - listeners though the voice was a person in the room with them and not recorded at all, especially some of the sound effects (footsteps and the like).

[sonare]

Originally Posted by Recording David

.

Simon uses an M-B disc, and because of that I bought one KNOWING that I would get the same results with the same mics (tonally speaking). You have used one several times with him.

The DIY method is not unlike buying lookalike mics and hoping they sound how they claim to-- unless the correct foam is used.

Also, I have used the feature to change the "aim" of the disc many times with good effect.

Rich