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Old November 14th, 2007, 08:33 AM   #1
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Recording audio from 8 people

Hi there,

I will soon have several jobs where I'll have to film and record "market research sessions" where 8 people discuss various products. The 8 people will be seated in a semi-circle, all looking roughly towards the interviewer (who will be sat next to the camera and will never be seen by the camera).

The "crew" will consist of just me. I'll be doing the lighting, sound and camera (but I wont be the interviewer!). I have an 8-track hard disk audio recorder (i.e. it can record 8 discreet tracks simultaneously)

My question is: what's the best mic setup to use in this situation? I've been weighing up two options:

Option 1) Give every person a wired lapel mic; record all 8 lapel mics to separate channels and mix in post.
  • Pros:
    • High signal-to-noise ratio because the mics can be positioned close to the subject's mouth
    • visually unobtrusive
  • Cons:
    • Takes a while to setup;
    • susceptible to russell and noises caused by clothing or jewellery;
    • might fall off;
    • susceptible to changes in recorded volume as the wearer turns their head whilst speaking (which will happen a fair amount as they engage in conversation with the people around them).

Option 2) Place directional mics (probably cardioid mics) on mic stands in front of the subjects. I would estimate that I should use 1 mic for every 2 subjects. Record each mic to a separate channel.
  • Pros:
    • I can setup the mics before the subjects arrive and when the subjects arrive, they just take their seats and we're ready to go;
    • insusceptible to clothing noise;
    • not very susceptible to changes in the direction of the subjects' heads;
    • half as many channels to mix down in post
  • Cons:
    • lower signal to noise ratio (i.e. more susceptible to noise like traffic noise);
    • visually quite obtrusive (which the client isn't keen on)

So - that's my thinking. Any thoughts?? To rule out a few other possibilities:
  • We can't have a boom operator
  • It's not acceptable to make the subjects hand round a mic - that will interrupt the flow of the session too much.
  • I almost certainly wont be able to hang mics from the ceiling

To be honest, I think I'll pack 9 lav mics AND 5 cardioids so I can decide whether to use lavs or cardioid mics when I arrive on location. If the location is nice and quiet then I'll use the cardioid setup; if it's a noisy location (and if I can't stop the noise) then I'll use lavaliers. The locations are scattered all round the UK so I can't do a reccie before the shoot days, unfortunately. However, I will call the owners of the locations to ask if there are any obvious sound issues.

Thanks,
Jack

Last edited by Jack Kelly; November 14th, 2007 at 09:03 AM.
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Old November 14th, 2007, 01:57 PM   #2
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Hi

If they are at a board table then cardioid mics on table stands would be best. One each and only good quality condensers such as AKG se300 or 480.

If they are seated then wired lavs should do it if you arn't too fussy about seeing cables. If cables are to be hidden then you potentially have a lot of work. Can't see you needing to hide the capsules though. Just watch out for noisey jingly jangly earrings or bangles ( which will jingle all the way through everything) and neck chains that could whack the mic's.

Radios would be good if you have the budget. Then people can move about a bit more.

The 8 track is a great idea if you are too busy to mix during. Maybe you could put the sum of all eight speakers on track one of the camera and the questioner on track two.

Don't worry about sound quality with lavs. As long as they are not being blasted with air from exhaling and the capsule is not touching any clothing which will rusle badly, you will have fine sound for these puposes.

I'd go for 8 wired sony ECM 77's. Omni pattern and facing down to help avoid potential breath blasting issues. They have a AA batery option which will help if your recorder has enough input gain but not 8 phantom power inputs. Sennheiser MKE 2's are good to. I just know I could source 8 sonys easier, particularly as I have 4 already.

As you say mic stands are too obtrusive so they are out.

Good luck
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Old November 14th, 2007, 05:13 PM   #3
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Have you considered one or two boundary layer mics placed on the conference table itself?
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Old November 15th, 2007, 04:28 AM   #4
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Hi guys,

Thanks loads for the great responses.

Sorry, I should have mentioned in my original post that there wont be a table in front of the subjects - the only furniture in the room will be the chairs the subjects are sitting on.

I agree - I should go with lapel mics and ask a the subjects (nicely) to remove any problem jewellery.

Many thanks,
Jack
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Old November 15th, 2007, 05:34 AM   #5
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Originally Posted by Jack Kelly View Post
I agree - I should go with lapel mics and ask a the subjects (nicely) to remove any problem jewellery.
While you mentioned you don't want a boom, you might consider a couple of mics on stands in addition to the lav mics. You can place a Y cable on a couple of the lav mics and free up a channel or two and use the mics on stands as additional sources.

I'm a huge fan of using both a lav mic and boom mic for situations like this, since I've had to use some of those tracks I never thought I would have to use.

Wayne
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Old November 15th, 2007, 07:11 AM   #6
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Y cable

with all due respect... Y cables should "Never" be used on input side of any device. they may be acceptable to send a source to two different devices but should never be used to save mixer channels. electronically this is a big NO NO. besides the electronic reasons the 2 devices will effect each other phase wise and impedance wise as well.
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Old November 15th, 2007, 07:32 AM   #7
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Hello Wayne and all,

It's really good that you brought this up. I was just paid for a local consult (post mortem) on a shoot where an attempt to create an audio "safety net" by combining mics to one channnel so the "safety net" mic went to the other channel resulted in compromised audio.

You have to be very careful with combining mics for several reasons. First there may be electrical problems due to altered impedances with Y-cords. Second, you don't have the ability to independently change the level of just one of the mics in a split. Third, having two mics open can allow phase problems when person A's voice gets into person B's mic and vice versa, because you can't turn down just one mic.

Not trying to be nasty here, but you can shoot yourself in the foot by taking actions you think are making your audio safer. Usually, the reason these actions are taken is because you are unsure of the right way to do the job or you really don't have a good solution.

Jack, sure, bring all your mics. Your first problem is that you have agreed to be a one-man-band. If you want really good audio in this situation, you need to pay attention to it. You need a qualified person to do that. You simply can not ignore the audio and get the best results. Condition change constantly during a shoot like this and someone needs to be there to keep things sounding good.

I would put each person on his/her own mic. I would not put two people on one mic. You'll have enough trouble keeping one person on mic correctly. Get foam pop filters for each mic. Someone ALWAYS eats the mic or pops like CRAZY.

Eight mics to eight tracks is a good solution in your particular case. Having a real audio person with a console with EQ on each channel and a comp/limiter on the stereo output before your cameras is the best solution; especially since you have no idea what the voice characteristics of the people speaking will be. It is not unusual to have to apply some moderately radical EQ to bring the voices together. Much more effort in post, but safer.

A good 8 channnel automixer can help but even automixers can't replace a good person mixing properly.

I wouldn't bother with "safety net" room mics, especially if it robs you of the tracks you need to get isoed single mics for each person.

Thanks for letting us play.

Regards,

Ty Ford
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Old November 15th, 2007, 07:48 AM   #8
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Quote:
Originally Posted by Jack Kelly View Post
Hi guys,

Thanks loads for the great responses.

Sorry, I should have mentioned in my original post that there wont be a table in front of the subjects - the only furniture in the room will be the chairs the subjects are sitting on.
Room has usable ceiling? - one would think of hanging two cardioid microphones from the ceiling (3:1 and maybe 'AB stereo').
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Old November 15th, 2007, 08:42 AM   #9
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Hi,

Thanks for all the replies.

Regarding the ceiling - no, I won't be able to hang mics unfortunately.

Ty - I completely agree with everything you say. Here's my current plan for the filming (it looks like there will only be 7 people to record: 6 subjects + one interviewer).

On the 8-track recorder:

* Channels 1-7 will be the wired lav mics.
* Channel 8 will be a cardioid on a mic stand (my "safety net")

On my DVX100a:

* Channel 1 will be a 416 mounted on the camera (I almost certainly wont need this recording but I've got the mic so I might as well use it!)
* Channel 2 will be a mix from the 8-track recorder.

I'll be filming a wide-angle of the subjects using my little Sony HC7e but I wont bother feeding any audio to this camera - it'll just record audio on its built-in mics which I'll use to assist with syncing in post and then ignore.

I'll plug my headphones directly into the 8-track mixer because the DVX's headphone amp hisses like crazy. This will mean that I wont be monitoring the 416 on the DVX but I doubt that will matter. During setup, I'll plug my headphones into the DVX for a minute to check there are no dodgy connections on the 416.

As an aside: I've used my 8-track recorder in conjunction with my DVX100 quite a few times and I'm sure they stay in sync.

Thanks,
Jack
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Old November 15th, 2007, 08:53 AM   #10
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One quick question:

I have 3 Countryman EMW wired lav mics so I need to hire 5 more lav mics. My local hire facility doesn't stock EMWs. Will it matter if I use different mics like COS11s? Will my EMWs match COS11s sufficiently well? (Remember that this isn't a broadcast gig - getting a solid recording for the best price is the name of the game on this project).

Thanks,
Jack
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Old November 15th, 2007, 10:14 AM   #11
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Quote:
Originally Posted by Ty Ford View Post
You have to be very careful with combining mics for several reasons. First there may be electrical problems due to altered impedances with Y-cords. Second, you don't have the ability to independently change the level of just one of the mics in a split. Third, having two mics open can allow phase problems when person A's voice gets into person B's mic and vice versa, because you can't turn down just one mic.
I agree with you. But just last week we had to do just this because we had 10 people on wireless and only 8 analog inputs on the Deva. We ended up placing the people with the fewest lines on the joined inputs, and it worked out OK for us. I also boomed, and we have that on it's own channel as well. But, I will admit that it's much easier to do when things are scripted and you know exactly what people are going to say, people aren't stepping on each other's lines and you can keep them separated physically by some distance. So, yes I know this isn't optimal (or recommended), but sometimes you simply have to do what you have to do to get things done.

Wayne
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Old November 15th, 2007, 01:35 PM   #12
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Y cable

with the wireless mics , you have a "buffered" output even when it is sending mic level out, with wired mics it is definitely a slightly different story with wired mics especially if they are balanced. one thing to keep in mind is that with a Y cable you are tying 2 output devices together. that is like connecting the muffler from one car to the muffler of another. not to mention phantom power issues (if its present). perhaps get some "mic combiners" for your tool kit, whirlwind makes some affordable ones, as well as pro-co. the Y cable has killed many output op-amp in various pieces of gear , non as sensitive as mic preamps.
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Old November 15th, 2007, 04:52 PM   #13
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This reminds me of a horror story situation I was in. I was the sound mixer and boom operator, they were sitting on a u couch 6' long and 6' wide on all sides. It was a nightmare. The place was small so there wasn't much maneuvering around and it was a 2 camera situation. Ideally there should have been 2 boom ops but they were too cheap to spring for a second mic.

I would say, you can do this whole thing with 2 booms on c stands and a lav on the moderator. Preferably 2 boom ops.

8 wireless mics sounds insane. If you have room in your budget for that, you have room for a 2nd person. If you have to use them. Clip them on the outside. Done right you won't get any rustle. And if there's excessive jewelery, especially bracelets, just have them take it off.

If you don't want to do boom, I'd say aesthetically and strategically place microphones in the semi circle or plant them.

If you're doing camera how are you going to monitor and troubleshoot sound?

And out of curiosity, which hard disk recorder are you using?
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Old November 15th, 2007, 05:06 PM   #14
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8 wireless mics sounds insane. If you have room in your budget for that, you have room for a 2nd person.
Try 10 wireless (at one point we thought we were going to have 12 people wired in one scene), with a two person crew, and where you don't have time to wire the talent until they get on set. Totally crazy. But producers are trying to skimp any way they can on productions these days.

Wayne
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Old November 15th, 2007, 07:52 PM   #15
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How about 1 handheld mic passed around?
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