Mic placement for filming an academic workshop

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dan_aka_jack

Well-known member
Hi there,

I am planning to video a 1-day academic workshop and I'd like to run my plans past the hugely knowledgeable DVXuser community to make sure I'm going to get the best sound possible within the limitations of the location.

Here's a quick summary of the event:

  1. Most of the event will take the form of a series of "relaxed lectures". There will be a single speaker up front doing most of the speaking whilst running a powerpoint presentation but there will be lots of spontaneous questions from the floor and discussion amongst the audience
  2. The audience will consist of about 30 people
  3. There are three people who will do most of the talking: the speaker, the host and the organiser.
  4. There is a loud roof-mounted air-con fan just outside the rear window of the location. I'm not allowed to shut down this fan during filming so we have to live with it.
  5. It's safe to assume that none of the audience or speakers have had prior experience of being filming.
  6. The filming needs to be as low-profile as possible and mustn't distract from or slow down the main event

In terms of mics, we've settled on this plan:

  1. 3 x wireless omni lav mics for the speaker, the host and the organiser
  2. 2 x hyper-carioids mounted on mic stands pointing towards the audience. The mics will be positioned on either side of the audience.
  3. Each mic will be recorded separately on a Korg D888 8-track recorder and mixed in post. As a backup, a stereo mix will be taken from the Korg and fed to the DVX100a doing the filming.

I'm pretty confident that we'll get great sound from the wireless lav mics (I'll make sure the mics are worn correctly throughout the day and that batteries are charged). My main worry is about getting a good clean recording of the audience. I have discussed three options with the organiser for recording the audience:

  1. Employing a boom op. Pros: good sound once the mic is in place. Cons: distracting for the audience, crap sound if an audience member starts speaking before the mic is in place
  2. Using a "hand-held" mic which audience members pass around. Pros: OK sound once the mic is in place. Cons: distracting, some handling noise is inevitable
  3. Using 2 stand-mounted mics. Pros: least distracting for the audience, respectable and consistent sound. Cons: it's pretty inevitable that we'll get some of the fan-noise on the audience recordings. I'm going to experiment with noise-sampling-and-rejection to see if I can remove that noise in post (it's continuous).

All comments would be most welcome!

Many thanks,
Jack
 
Is there a question and answer session with the audience? If so the 2 stand option would work great. Audience wanting to ask a question just line up near the mic. I have seen this done a number of times with great success
 
Hi there,

Thanks loads for the reply. The audience will be asking spontaneous questions throughout the day. I'm pretty sure the client wont want the audience members to have to stand up and que to ask questions - the whole vibe is that the discussions should be very relaxed and "free-flow". Audience members will be asking questions from their seats.
 
Hang overheads from the ceiling. Rent a bunch of Omni's. You've got more than 8 tracks I think, so use them up.

Four or five omni's hanging from the ceiling has worked for me. Only other resort is the podium line up.
 
Thanks for the reply. Yes, you're right - I have 8 channels to play with.

I like the idea of hanging omnis from the ceiling. I'm not sure I'll actually be able to hang them from the ceiling so each omni might have to be on a high mic stand. Although now you've got me thinking - the room has a false ceiling - maybe I could buy five of those "false ceiling squares", attach my mic to my squares and swap out the existing squares before the event (and then replace the original squares after the event, of course!)

Are omnis definitely my best bet? Could I use directional mics like hyper-cardioids and point the mics away from the fan noise at the back of the room and towards the audience?

Thanks,
Jack
 
Hmm... I have three omni-directional lavalier mics (Countryman EMW XLR-terminated) that I could suspend from the ceiling. I'm thinking that these mics are so small and light that I could just use camera-tape to attach the cable to the ceiling and let the mics dangle down.
 
Yep, you can hang them close since they are very small - like about 7+ feet from the ground to mic. Lavs tend to need to be close buuuuuuuut you could do this. Make sure you use/rent/buy 4 or 5 of them.

BTW, how big is the room? Oh and are you using a PA system for monitoring back to the folks there?
 
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Thanks loads for the reply.

There's no PA system - the only mics in the room will be the mics I rig up for the video recording.

The room is probably about 20m x 20m x 2.5m high. I'll put some photos online later today.

How important will it be that the 5 "hanging lavs" are matched? Could I use my three EMW mics plus two hired lav mics?

Thanks,
Jack
 
Hi,

Here's a pic of the conference room:

DSC_0133.jpg


More pictures here on my website.
 
My suggestion to get you the cleanest noise possible, instead of using a boom op, hire someone to walk the room with a dynamic microphone, wired or wireless (beta 58 would be good here, with a foam windscreen) and when the audience member asks a question, they'd have to ask it into that microphone. Train the person moving the mic around the room how to handle it to reduce the noise. The best part is that the dynamic mic likely won't pic up the fan noise.

I've seen videos just like you're describing where they boom, and it almost always doesn't sound great, even if the space is small, because the boom doesn't get into position in time. If you watch an infomercial, the audience always speaks into a dynamic microphone when they ask questions, and it always sounds great.

-Steve
 
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