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Author Topic: Oddball microphone techniques  (Read 55920 times)

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Offline Gutbucket

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Re: Oddball mic techiques that worked - evolution to 'Bug Eye' rig
« Reply #60 on: April 17, 2008, 10:16:59 PM »
Hey Moke, can you explain how you made the Jecklin disk?

Here are some photos of my DIY Jecklins, using the same embroidery hoop starting point.  I got this together a year ago based on everyone else's ideas in the TS Jecklin threads (thanks Mike!).  As usual, mine are a bit oddball, first because they are ellipses not disks. The idea behind the ellipse was to give more baffle separation for forward arriving sounds while keeping the overall size of the thing as small as practical, allowing for less baffling effect for the ambient room information from above and behind. The ellipse shape  also just looks cool.

Going possibly a bit farther than necessary to damp reflections off the surface of the baffle, I listened to the reflected sound off of various materials by angling the material like a mirror in front of a speaker and listening though a tube placed near the reflection point. Doing that, I could judge pretty well how much sound and of what frequency range was reflected by the material. I tried various foams but settled on a layer of short cut pile carpet remnant salvaged from the shipping department at work that seemed to absorb the midrange best, covered by a layer of felt moving blanket that really sucked up the higher frequencies. I thought about using some cork material as the rigid center board portion (pic below), but ended up using a piece of three layer corrugated cardboard to keep the weight down and possibly form a bit of a 'constrained damping layer' with the heavier carpet sandwiching it on either side.  I covered each side in typical dead rat style faux fur for appearance more than anything else (it's supposed to be nearly transparent to sound used for 'rats' so I used it for looks more than it's sound absorption.. maybe it damps some top octave) and wrapped the wooden hoop with a strip of 2" black gaffer tape.  Just cut the pieces, assemble the sandwich and camp the hoop. Then figure how to attach it to your stand (or light fixture  ;)) I used a short square section wooden dowel that fit into the painter pole I was using as a mic stand at the time.

Photos-
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Offline Gutbucket

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Re: Oddball mic techiques that worked - evolution to 'Bug Eye' rig
« Reply #61 on: April 17, 2008, 10:20:52 PM »
More showing the sandwich of materials, and one with the unused cork and a regular circular hoop-

[edit- one side shown only, obviously there is carpet, felt and fur on the other side too.]
« Last Edit: April 17, 2008, 10:22:26 PM by Gutbucket »
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Offline Gutbucket

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Re: Oddball mic techiques that worked - evolution to 'Bug Eye' rig
« Reply #62 on: April 17, 2008, 10:38:50 PM »
OK, below is a photo of the other oddball Jecklin that I never worked up the guts to fly.  Same construction as the smaller one. Reasoning for the fast-food super meal sizing to follow in another post. The sandwich photos above are of this one, which is why the scale of things may appear a bit off. I sacrificed the fur cover for the 'possum' windscreen to run the TL's coincident in a breeze.  This one is the big boy. Lookout Ray Kimber!

it's based on another, larger ellipse embroidery hoop. Small disk for comparison and hand photo for scale-
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Offline illconditioned

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Re: Oddball mic techiques that worked - evolution to 'Bug Eye' rig
« Reply #63 on: April 17, 2008, 10:45:12 PM »
OK, below is a photo of the other oddball Jecklin that I never worked up the guts to fly.  Same construction as the smaller one. Reasoning for the fast-food super meal sizing to follow in another post. The sandwich photos above are of this one, which is why the scale of things may appear a bit off. I sacrificed the fur cover for the 'possum' windscreen to run the TL's coincident in a breeze.  This one is the big boy. Lookout Ray Kimber!

it's based on another, larger ellipse embroidery hoop. Small disk for comparison and hand photo for scale-

Thanks for the details.  Got to get in gear and make one...

  Richard
Please DO NOT mail me with tech questions.  I will try to answer in the forums when I get a chance.  Thanks.

Sample recordings at: http://www.soundmann.com.

Offline Gutbucket

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Re: Oddball mic techiques that worked - evolution to 'Bug Eye' rig
« Reply #64 on: April 18, 2008, 12:16:27 AM »
Richard,

Your application halfway back in the room is what stirred me to dig up these photos.  I experimented with various omni spacings using the rabbit ear TV antennas and the small disk and I think the Jecklin technique (with a normal sized disk) works best when used up close to the performance.  My experience using the smaller disk with omnis farther back was less than ideal. I ended up preferring a wider un-baffled omni spacing. In order to have the disk baffle the mic for sounds on the opposite side of a normal sized disk, the mics need to be pretty close to the disk surface - It's just a matter of geometry.  Recording at a distance I found that 'tight to the surface' spacing cut the highs unacceptably and didn't provide enough distance between the mics to develop the nice open spaced omni sound at mid and lower frequencies. 

A bigger disk would allow for wider mic spacing while still providing baffling for sounds at the edges of the soundstage.  Of course the size of the disk needed to do that grows rapidly as you move deeper into the room and/or move the mics further apart.  You soon end up with something the size of the Kimber monster.  You could try moving the cards towards the back edge of the disk to increase the effective baffle area and narrow the 'shadowing angle' somewhat from deeper in the room.  I also considered making two small disks and spacing them apart. That would allow enough distance between mics for a decent A-B spaced omni recording at mid & low feqs but get the disk surface close enough to each mic to provide a decent shadowing effect for the high end. Something like that might be unpractical with a mic stand considering sight lines, but could work from the ceiling.  If you are pointing the Beyers directly forward and not using the pattern directionality for stereo purposes, they are like omnis as far as imaging is concerned and you either need to space them far enough apart or have the baffle shadow the mics for stage originating sounds from the opposing side.  That's my working theory anyway.

Interested in other thoughts on all this,

Lee
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Offline Gutbucket

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Re: Oddball mic techiques that worked - evolution to 'Bug Eye' rig
« Reply #65 on: April 21, 2008, 09:20:32 PM »
Oddball comp fer shur.

Listening to the right channel only, alternating DPA tracks, the 4028 sounded slightly hotter, adjusted volume by ear and the bass is very similar, more midrange focus with the 4028's, more room reverb with the 4060's (the attack of the pizzicato fiddles).  The drier 4028 is nice at that distance, though the applause and reverb is still very natural, just slightly attenuated and that's what I love about those sub-cards.  Alternating between left channels the tone difference is clear. The bass leanness of the  mv692's is obvious but that top is so sweet.  Tonally the balance of the mismatched pair is really complementary if you ignore the wacky imaging.. didn't listen in mono.

Bummer on the DOA.
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Offline hypnotoad

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Re: Oddball mic techiques that worked - evolution to 'Bug Eye' rig
« Reply #66 on: April 21, 2008, 09:50:57 PM »
Those bent rods are pretty cool Gutbucket.

 :)

Offline Gutbucket

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Re: Oddball mic techiques that worked - evolution to 'Bug Eye' rig
« Reply #67 on: April 22, 2008, 08:49:16 AM »
Those bent rods are pretty cool Gutbucket.

 :)

Thanks, I really liked that application.  Unfortunately I haven't had another chance to do that since.

[edit, I got to do this again a few months back for Stanton Moore trio.  4060s on stalks flanking the Peluso P-Stereo in M/S]
« Last Edit: November 19, 2008, 06:03:49 PM by Gutbucket »
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Offline Gutbucket

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Re: Oddball mic techiques - evolution to 'Bug Eye' now 'Quad Eye' rig
« Reply #68 on: November 19, 2008, 05:57:58 PM »
The bug eye rig has sprouted a few more antennae.

First some back story-
I've been playing around with some surround sound recording ideas since last spring.  My approach is to not compromise my standard two channel stereo recordings by changing the stereo mic array, but to add two optional, additional mics recorded as center and back channels.  I've been doing this for a while now for low-profile recording using baffled omnis and the results have been highly encouraging- adding another dimension of reality to what I had previously considered very good stereo recordings that already convey the illusion of 'being there'.  It has been so encouraging that I decided to try and apply the technique to a standing, open rig, somehow without the baffles that would block sight lines.

I'd already been running two simultaneous stereo rigs for some outdoor festivals which is great for comparing techniques and equipment and have sometimes toyed with surround playback. I'd usually run my 'big rig' with ADK TLs or Pleuso P-Stereo mic in say Blumlein a few feet in front of the little spaced omni bug eye rig pictured here previously.  The two micstand formation formed a sort of triangular Deca tree shape.  Setting up the two separate stereo rigs that way allowed me compare the two stereo recordings on their own, or to try sending the blumlein pair to the front L/R speakers and the omni pair to the surround speakers. I also played with summing the blumlein pair to form a single forward facing fig-8 (M/S technique) and using that as a center channel along with the L/R omnis for L/C/R playback.  All good fun but none of those surround experiments really added that much over the stereo recordings, certainly nothing like the baffled surround recordings I've been making. 

I figured that the baffle was an essential element to provide enough directionality and isolation of sound between front and back channels with the meter or so spacing between mics that I was using for practical reasons. Eliminating the baffles I needed something to provide directionality to the highly omnidirectional miniature 4060s.  I considered using clear plastic CD jewel case covers or the clear 'CD's that cap the stack on CDR spindles like mini-baffles and boundary mounting the mics to them, one at the end of each telescopic antennae, but the more I thought about it the more that seemed a bad idea.  I instead decided to return to using the APE-like Nerf foam balls I've pictured here previously which provide some top end directionality, seem in keeping with the obvious Decca tree using classic Neumann M-50s influence or the modern DPA surround tree using omnis with APE attachments. They are also much more practical to use and to keep less visible.

I've used the rich sounding and costing DPA surround tree and APE attachments as design inspiration and developed the 'poor man's' version that you see below.  Other big influences that have shaped or confirmed my thinking on this are Michael Williams' Magic Arrays for simultaneous recording of 1,2,3,4,5 or more channel sound, each of which stands on it's own, with a single array and his previous MMAD data for 4-channel quad arrays using omnis and subcardioids.

I'll just address the non-low profile open recording here and the modification of the bug eye rig I've posted about previously. The signal path is (4060s > CA-Ugly > R-09) x2.  One rig records the L/R pair and the other the C/B pair.  For playback I currently hook up both recorders' outputs to the 6-channel DVD input of my stereo amp (splitting the back signal to both surround speakers) and play both recordings simultaneously. It takes a few quick jabs of pause/play to match up a percussive impulse and sync both machines, but they do not seem to drift audibly over the course of a 90 minute recording. Unlike matrixing a 4 channel recording the signals are not summed and are somewhat less susceptible to comb filtering problems if slightly off sync.  I have not found the time to play around with the recordings on the computer in post yet, but plan to eventually look into syncing the two stereo recordings (L/R & C/B) and encoding to 24/48 DTS surround.  I mostly play everything off the computer into the home stereo these days but I could also burn DTS encoded surround CDs or DVDs. I also plan on trying various methods of decorrelating the mono back channel feeding the two rear surround speakers.  Any ideas on ways of doing that are very welcome.  I need a four channel output sound card for my editing machine before I can do any of that.

First a photo of the previous dual rig setup. This was from a month ago, Peluso P-Stereo up front, antenna spaced 4060s one row directly behind. Here the 4060s are not mounted in the foam Nerf balls and so are 'fully omni'.  Both sound very nice as stereo recordings but there is not enough distance between rigs or imparted directionality to make the 4060s useful as surround feeds. (five rigs can be seen, the Peluso is in front, the antenna spaced 4060s are directly behind another rig)-
« Last Edit: November 20, 2008, 12:01:20 PM by Gutbucket »
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Offline Gutbucket

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Re: Oddball mic techiques - evolution to 'Bug Eye' now 'Quad Eye' rig
« Reply #69 on: November 19, 2008, 06:01:57 PM »
Now behold the Quad Eye rig.

These are from Bear Creek this last weekend. Here Saturday morning down low and up front for Jim Weider's Project Percolator with a few closeups-
« Last Edit: November 19, 2008, 09:48:17 PM by Gutbucket »
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Offline Gutbucket

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Re: Oddball mic techiques that worked - evolution to 'Bug Eye' rig
« Reply #70 on: November 19, 2008, 06:06:40 PM »
I painted the green Nerf balls charcoal gray with automotive vinyl and fabric paint. A bit less alien but they don't glow so much.

Rigged higher and farther out from the stage-
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Offline Gutbucket

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Re: Oddball mic techniques that worked - evolution to 'Bug Eye' rig
« Reply #71 on: November 19, 2008, 06:13:15 PM »
Stage lip again (different stage) for Robert Walter Trio, here I have foam windscreens on the balls which are just cut down cheapo Shure ball mic style foams to form a half sphere, pinned onto the foam balls.

Soundcheck-

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Offline Gutbucket

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Re: Oddball mic techiques that worked - evolution to 'Bug Eye' rig
« Reply #72 on: November 19, 2008, 06:14:44 PM »
Live set-
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Offline Javier Cinakowski

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Re: Oddball mic techiques that worked - evolution to 'Bug Eye' rig
« Reply #73 on: November 19, 2008, 06:15:50 PM »
that is a sweet set-up....  Thanks for sharing!
Audio-Technica AT8022-> Tascam DR-100mkIII

Offline Gutbucket

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Re: Oddball mic techiques that worked - evolution to 'Bug Eye' rig
« Reply #74 on: November 19, 2008, 06:18:40 PM »
Inside the music hall for New Mastersounds, Skerik as guest-
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