Audio for filming a panel/lecture

[ronin99]

Hello, I will be filming a panel of 4 speakers and I'm trying to figure out my game plane for recording audio. I’d prefer to figure out a setup where I could run the mics directly to the camera (to avoid syncing) if possible but since the camera has 2 xlr inputs and this will feature 4 speakers I don't know if that will work. I guess if the speakers are stationary, we could run the mic feed to the camera or place our mic on the podium. Maybe use a mic splitter? Would a dynamic mic on the podium be the best for this scenario (I have a shotgun, lav, and H4N as well. However, I am willing to rent some audio equipment if necessary.) Thank you

[TheDingo]

Does the room have it's own sound system, or are the speakers addressing the audience with no microphones?

If the room does have it's own sound system, then you need to figure out how to tap into this with your camera or an external audio recorder. Getting a line-feed out of the mixer that you feed to your camera or audio recorder is ideal.

For rooms that have no sound system, I will use either boundary mics on the speakers table or a Zoom H2n recorder in surround mode plunked down in the middle of the panel of speakers.

If they are all speaking at a podium, then tapping in to the podium mic works best, but you can also get by with placing a small digital recorder ( like an Olympus LS-7 or LS-11, or Zoom H1 ) with a tiny tripod on the podium. ( just make sure you tape the tripod to the podium )

Synching long audio recordings with your video is actually pretty easy if you know how. I can synch 6 hours of audio with 6 hours of video in a few minutes, using a $20 piece of Windows audio software. When working this way, you want to shoot one long video with one long audio recording, as synching lots of little clips will take forever unless you are using something like Plural-Eyes to do this for you.

[Steve House]

...

Synching long audio recordings with your video is actually pretty easy if you know how. I can synch 6 hours of audio with 6 hours of video in a few minutes, using a $20 piece of Windows audio software. When working this way, you want to shoot one long video with one long audio recording, as synching lots of little clips will take forever unless you are using something like Plural-Eyes to do this for you.

Don't discount the prevalence of sync "drift" with long takes. Unless the clocks in the camera and audio recorder are 100% on-spec, the two files can play at slightly different rates and over a long take what is in sync at the head will slip out of sync by the end.

[TheDingo]

Don't discount the prevalence of sync "drift" with long takes. Unless the clocks in the camera and audio recorder are 100% on-spec, the two files can play at slightly different rates and over a long take what is in sync at the head will slip out of sync by the end.

I always expect drift, and I can correct the drift on very long video/audio tracks in a few minutes. I have found that most modern digital cameras/recorders have a linear drift that is easy to fix ( in the audio track ) with the right software. I have been doing this sort of thing almost every week for the past 5 years when shooting very long corporate/medical lectures.

[ggrantly]

If you use a portable recorder, how do you set levels and or monitor your recording?

Grant

[TheDingo]

If you use a portable recorder, how do you set levels and or monitor your recording?

Some portable prosumer recorders have a low noise-floor ( i.e. Tascam DR-100 MK2 has noise floor of -80 dB or better at most settings ), which means that you can set a low recording level ( say -20 dB ) which will provide you with 20 dB of head-room to record audio without clipping, and at least 60 dB of dynamic range.

Some portable recorders also have a good limiter circuit ( Olympus, Sony, Tascam ) which will prevent clipping on loud sounds, so you can set higher recording levels and still get a usable recording of loud sounds. Be careful to test the limiter circuit, as I've found that with some low cost recorders the limiter feature lowers the quality of the audio recorded, so the audio doesn't clip but it doesn't sound very good.

For monitoring, a good pair of closed-back headphones will do the job. ( Sennheiser DJ headphones are cheap and quite good if your budget is tight )

When I am far from the recorder, I use a Sennheiser UHF system to send audio to the recorder and to my camera, which allows me to monitor from a distance.

I always like to have redundant audio recordings, so I will use multiple recorders ( either at the podium, or on a boardroom table, or directly connected to the room's sound system ) to make sure that if one recorder fails I always have a backup. ( I've had one audio failure in 5 years and 400 hours of shooting )

[ggrantly]

Hadn't though about wireless monitoring.

Grant

[ronin99]

I will be tapping into this board and I was told I would need a balanced 1/4 inch to xlr.
Mackie 1402-VLZ3 14 ch. compact mixer [1402VLZ3] - $429.95 : Audio Depot, Madison, WI

The audio guy told me that it will be running "hot", I'm assuming that means near peaking? He also said he can send the signal to me pre or post (I want to say fader but I'm not sure)?

I'll be running that hard wired into the camera (I'll have to do some cable management). Then, my plan was to place an external recorder on stage and a lav near the podium mic or draping off a speaker. What do you think?

[Rick R]

Yes, he means Pre or Post fader. A post-fader send would have the house mixer's fader moves and channel EQ on your mix. Pre-fader would not, and is 'usually' better... (depending on the situation) Confirm your recorder and camera will except a +4dB balanced signal. Normally even a 1/8" mini jack line-in will not handle a +4dB signal, which could have peaks above +20dB. However the Aux. pre/post send can be turned down a bit, via the channel or master send. It cannot be turned down enough for mic level though. So plan on bringing some 10, 20, 40dB pads. and/or a DI box regardless. A Iso tranformer comes in handy as well. I never leave home without a few IL-19s if interfacing with an external system.
Addendum: As I recall, the Mackie VLZ's arhitechture has the channel EQ on both pre/post fader sends which should not be a big issue. Your other option is a mic-splitter.