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Old February 3rd, 2017, 03:06 PM   #1
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Question about figure 8 capsules

I've always been curious about this highly specialized (and expensive!) capsule. I know it's primary application is for stereo recording, but does it have other uses? I've posted in here previously about micing a rectangular table from overhead with a stereo rig. I find I also need to mic a smaller table with only four people seated. Let's say it's a small round table with four people seated around it. There is food and clattering tea cups on the table. Couldn't I suspend a single figure eight right in the middle at mouth level and get the whole thing? I'm hoping that the nature of the figure eight pattern would help minimize the noise on the table. Do I really want an omni? It would sure be cheaper. The figure 8 capsule would be either AKG blueline or Schoeps, budget permitting.
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Old February 3rd, 2017, 05:43 PM   #2
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Re: Question about figure 8 capsules

I use a Schoeps figure 8 mic one of my normal mics. But I'm not sure why you mention it with stereo in the "same breath" - a stereo mic it isn't. If you want to use it to capture stereo you'll need to combine it with another mic, either a second figure 8 at 90 degrees to the first one (Blumlein) or together with another mic. (I've used everything from omni to hypercardioid) in the M/S (mid-side) configuration. I think there may be an additional way of using two spaced figure 8's but haven't ever done it myself.
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Old February 3rd, 2017, 05:59 PM   #3
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Re: Question about figure 8 capsules

A figure 8 microphone is NOT a "stereo" microphone. It is a MONO microphone with a specific polar pattern. Using a figure-8 microphone along with a cardioid microphone, and doing some fancy signal processing yields a virtual "stereo microphone". This is called the "M-S" (Mid-Side) technique.
ref: https://en.wikipedia.org/wiki/Microp...de_stereophony

There is also the "Blumlein Pair" where you take TWO figure-8 microphones at 90 degree offset to cover the complete 360 degree circle in "stereo".
Ref: https://en.wikipedia.org/wiki/Blumlein_Pair

A figure-8 microphone has (ideally) identical forward (0 degree) and reverse (180 deg) pickup sensitivity, polar response, frequency response, etc. And very deep rejection on the sides (90 deg and 270 deg).

If you have four people equally spaced around a round table, and you use a figure-8 microphone, you have you choice of picking up two of the people fine, and ignoring the other two, or else having all four of them significantly "off-axis" Neither of those options seem desirable to me. I can't see how a figure-8 microphone would be particularly helpful in that situation?
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Old February 3rd, 2017, 07:07 PM   #4
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Re: Question about figure 8 capsules

Yes I'm aware that in stereo recording you have to combine the figure eight with a second, cardioid microphone. I thought that was too obvious to specify. Perhaps I misunderstand the polar pattern though. I had understood that it captures sound perpendicular to the mic. So I wondered If it could be hung over the center of the table (pointed down), with the sound rejection applying above and below.
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Old February 3rd, 2017, 09:20 PM   #5
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Re: Question about figure 8 capsules

I got what you meant originally.

I think it would depend on what the off-side lobe contributes to the overall sound when only one person speaks.

If the inverted phase and overall response of the off-side lobe sounds terrible when the person on the other side of the mic speaks, you'd be sunk because there would be no way to remove that part of the signal when using the mic this way for 4 distinct people around the table.

Since you wouldn't be mixing the figure eight mic with another mic for mid-side stereo, it would depend completely on that mic itself, its response to off-lobe sounds, especially the room reflections (and the effect of inverting the phase of the split signal in relation to who was talking at the time).

I have used a single-point stereo mic for micing two people sitting at the same table in a typical office. That absolutely required checkerboard editing or the off-axis capsule sounded terrible when the "opposite" person spoke.

Checkerboard editing was possible because it's essentially two mics each with one lobe mounted in a single mic head but with two output signals. Having two lobes in a single mic would make checkerboard editing impossible for the off-side lobe and would depend on what effect inverting the phase of the split signal had on which person or combination of people were speaking.

But, since figure eight mics are used for two singers facing each other or two people blogging, maybe I'm all wet and I'm overblowing the effect of the off-lobe response for 4 people. How lively is the space you will record in? Also how low can you hang the mic without it being in the shot? Lastly will the dialog be mostly one at a time or a lot of simultaneous talking?

Last edited by Jay Massengill; February 3rd, 2017 at 09:59 PM.
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Old February 3rd, 2017, 09:34 PM   #6
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Re: Question about figure 8 capsules

I don't know what you mean by "pointed down"? Do you mean with one lobe pointing toward the center of the table and the opposite lobe pointed at the ceiling above the table? I can't see how that would be an advantage? It would actually increase pickup of extraneous noise (like handling dishware, etc.) by focusing the "forward"(?) node toward the noisy table-ware and putting the subjects rather in the rejection node. And then aiming the rear node up at the space above the table which could be disastrous depending on the acoustics and ambiance of the space. I just don't see any way that a figure-8 microphone would be of any advantage in that situation.
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Old February 3rd, 2017, 10:01 PM   #7
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Re: Question about figure 8 capsules

He meant hanging the mic straight down, with the two lobes covering two people each, on opposite sides of the table.

I think it would be easier editing to hang two hypercardioids in a coincident pair (pointing downward) but at 120 to 150 degrees from each other. Each mic covering two people, spaced in two pairs instead of evenly around the table. Each pair of people would be in the null of the opposite hypercardioid.
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Old February 3rd, 2017, 10:35 PM   #8
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Re: Question about figure 8 capsules

Quote:
Originally Posted by Jay Massengill View Post
He meant hanging the mic straight down, with the two lobes covering two people each, on opposite sides of the table.
OK, that is what I meant by "having all four of them significantly off-axis".
And to add insult to injury, the two on the "backside" of the mic are 180 degrees out of phase.
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Old February 4th, 2017, 08:54 AM   #9
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Re: Question about figure 8 capsules

Thanks everyone for helping explain. I'm starting to see where my confusion is. I didn't realize that the polar pattern indicated two distinct lobes. I had thought it just indicated that audio was captured perpendicular to the mic in ALL directions, so it wasn't clear to me that in the scenario I described two of the speakers would be off axis. I thought all four of them would be on axis and the table and ceiling area would off axis.

So I'm guessing then that I really just want an omni maybe, hung at mouth level, or a cardiod somewhat higher. It doesn't matter if the mic is in the shot, particularly with such a small footprint. The table is quite small. More than anything I was hoping to find a scenario that would reduce the table noise.
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Old February 4th, 2017, 10:02 AM   #10
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Re: Question about figure 8 capsules

A hung omni could be as simple as an end-address lav - small and unobtrusive. One of the lavs with a non-flat response curve (e.g. Sony ECM-44) might be a very good choice.

If your talent are leaning in and vocal this might work well. If one or more of them speaks quietly, so quietly that you need to mix on-site and/or in post any room reverb and background sound will come up with them.

You start to get into territory where a lot will depend on the specifics of the room. "Booming" the participants in this way can be a *very* natural sound, but, a good boom operator will mix with the mic position to match loudness of participants by ear. If you're in control of the set, you could hang the lav off a boom on a stand, run a couple takes with some close monitoring, and adjust it's position.

But if the room is lively and the table is big this whole approach is going to need some close attention because you may need to bail out. If you have access to the room you could test it!

Throw down a tablecloth to help damp the sound of cups, pens, etc. hitting the table. Make it white or black, warm or cold to work with your lighting design...
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Old February 4th, 2017, 11:36 AM   #11
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Re: Question about figure 8 capsules

It helps to see the pattern in 3D. You were thinking it had a "doughnut pattern" like a dipole antenna. I wish we could make microphones with that pattern. But alas, that can't be done at audio frequencies. The illustration with the Shure label shows a figure-8 (typically ribbon) microphone pattern. The pattern labeled "Half-Wave Dipole along Y Axle" is probably what you thought was "figure-8" I wish. The "ball" labeled "Isotropic" is essentially an omnidirectional microphone.
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Old February 4th, 2017, 02:12 PM   #12
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Re: Question about figure 8 capsules

Thanks guys!
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Old February 4th, 2017, 04:51 PM   #13
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Re: Question about figure 8 capsules

For years a ribbon fig 8 was the standard way to record an interview, with the one mic covering the presenter and the respondent perfectly well. In fact, the BBC even had interview tables with a hole in the middle so they could pop up from the centre. Hanging them is a pain because the mic and the support interfere with vision.

You could use two fig 8s, in what appears to be a Blumlein setup to record 4 people with two to each channel. This would give a little more control than using an omni, and of course the omni would also capture lots of the reflections from the table.
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Old February 4th, 2017, 09:17 PM   #14
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Re: Question about figure 8 capsules

As we are onto ribbon mic's and as a side note I have been using a couple of low cost Chinese fig 8 mic's (Auna and MXL) to record guitars and percussion as the 8 polar pattern can be quite useful for two handed shakers and twin bongoes.

Also I spent all of last night with two fig 8 lip ribbon mic's plugged into my Calrec Apollo mixer doing live football commentary.

Someone on another forum was also asking about the old days of recording film dialogue and the RCA fig 8 ribbon mic featured a lot and if you want to replicate the Beatles Ringo drum sound a coles 4038 fig 8 mic is a must.
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Old February 5th, 2017, 06:52 AM   #15
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Re: Question about figure 8 capsules

Quote:
Originally Posted by Marco Leavitt View Post
More than anything I was hoping to find a scenario that would reduce the table noise.
That's normally done in prep. It's the application of substances like felt to the bottom of teacups, spraying down news print with substances like water to eliminate the rustles, etc. Hollywood does this all the time -- they eliminate all environmental sounds so that they record only dialog in real time. All the clinks, rustles, heel clicks, rubs, etc. that you hear in the final film are all Foley or sound effects that were carefully added in post.

You can do much the same if you can control a situation. Even with untrained "talent" you can still apply felt to the bottom of glasses and cups, use a table cloth instead of a bare wood table, etc. But lacking that, just remember that signal to noise ratio in audio often becomes just an exercise in getting the mic positioned properly -- close to the signal and away from the noise.

EDIT: And learning your polar patterns so you can use the nulls effectively too. The nulls in a figure 8 microphone are the most effective of any polar pattern in suppression of off-axis sound. But it sometimes takes some creativity to use them well.
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