What mic would you use?
 

If you didn't have a boom operator, what kind of mic would you use to record a group of people? Picture a group of eight sitting close together and having a discussion. Multiple people may speak at the same time. I was thinking a single condenser set to omni pattern near the center.

If I was faced with that challenge, I would use at least two good condenser microphones.

Are you recording just audio or video also. If video, then I would attempt to hang the two condensers above the group, just out of the frame.

Yeah, I'm doing video also. That's a good idea. What I could do is have two omni lavs hanging down from the ceiling on either side and then fade in the best audio for each particular person.

Were it me, I'd use two or three boundary mics in a star pattern.

I'm not very familiar with boundary mics and their advantages. What would be the advantage of using boundary mics instead of lav mics? Also, are we talking mono or stereo boundary mics.

By the way, I made the voice over box in your article. I guess it's just common sense, but I probably wouldn't have thought of it. Very cool!

Boundary mics are different from the usual mic in that they're designed to be placed flat on a surface like a table or wall with the diaphram very close to and parallel to the surface they're on. They take advantage of some peculiar properties of sound waves in air at the surface of reflective planes to gain increased sensitivity and better tonal balance than a conventional mic placed at similar distances from the sound source. You find them used a lot in conference rooms, video conferencing, security and surveilance operations, etc.

So for your group, put perhaps a round coffee table on the set and seat them in a semi circle around one side. Put a boundary mic in the centre of the table or 2 or 3 of them evenly spaced and about halfway out to the edge around the side of the table with the group.

Ok, what if there were no table? What if a group of 8 are just sitting in folding chairs? What would sound better: two boundary mics on the floor or two lav mics dangling from above (I think the lavs could get closer to the sound)?

Whatever you can get closest to the source is likely your best bet. If we're gonna start playing "what if?" rather than dealing with an actual scenario, then get a good boom op with a sensitive cardioid on the end of the boom.

Mics above might get a bit closer but boundary mics are 6db more sensitive than comparable regular mics by viurtue of the physics of the way they work. If you want a coffee table, put one there - it's your set, make it look like you want it! <grin> Seriously, if you don't want a low table in your shot, you could frame closer so it ends up out of frame. Of course, you might want the look of a stark empty room except for simple chairs even in long shot for the visual dramatic effect. If so, boundary mics are used on the floor in many stage productions. It needs to be a hard surface floor, wood or concrete, for it to work - carpeting won't cut it. If the room is carpeted you can fasten the mics to sheets of plywood which you lay on the floor in front of the talent or sheets of heavy plexiglass (to avoid casting shadows) to prop up in front of the group just out of frame. Or as Douglas suggested, get a long boom and a good boom op with good reflexes.

I don't know what the scenario is going to be. I'm supposed to go over to someone's house and video tape them discussing something. All I know is there are going to be eight of them.

I really don't want to annoy them with a boom mic and I don't think they would talk as freely if someone were pointing a mic at them every time they started talking. The point is for them to forget about being filmed.

The boundary mic on a coffee table idea would probably be the most inconspicuous.

Thanks for the explanation of boundary mics Steve.

I can't claim any expert credit, just a good memory for what I've read.

You're going to be there with a camera and you're worried about a boom mic?

Don't.

Regards,

Ty Ford

Good point, but I don't want the cameras moving either. This is a candid event with people who are not going to be real happy about being filmed in the first place, so I want to keep the mics, cameras, and lights as discreet and stationary as possible. The content is most important, quality is secondary but still important.

I don't think a boom would be a good choice anyway for recording a group of people who may all be talking at the same time. Even a pro would have a hard time doing that.

Boundary mics seem to come in a variety of flavors: stereo, cardoid, hemi-cardoid... I don't see any omni's. The stereo At854R could be placed in the middle of the group and then I'd have two channels to to mix in post. Of course for that price, I could buy four of the cheap ones. I'm just not sure about hemi cardoid... I'll have to look up the polar pattern to see what it looks like. Any recommendations?

The polar pattern of the hemi-cardoid looks the same as a regular cardoid, so two or three Pro-44's would probably get the job done.

There are no omni's because none of them pickup from below the surface they're mounted on. Hence the pickup pattern is a like hemispheric bubble resting on the surface over the mic (cardioid) or "half a bubble" -imagine the mic element in the centre of an orange that's been cut into quarters, once around the equator and once pole-to-pole, resting on the table. For stereo, cut that into to give you two 1/4 bubbles side-by-side.