multi-person hall sound system with recording

[humbuk]

Sometimes I record discussions, which, in addition to recording the sound itself, involve sounding the space for the listeners. So far I have been using a bodypack transmitter with a lav microphone. The audience soundstage was small, so it could be used, but it was bordering on crosstalk from the speakers and also feedback. Now I will have to sound a bigger hall and I am afraid that it will no longer be usable because of the feedback. A headset mic or a hand mic would certainly be more appropriate in these situations. But is it possible to use a lav mic on the chest in these situations, is it commonly done in practice? Or are headsets or hand mics always used? How to prevent feedback and crosstalk? Thanks a lot

[Rick Reineke]

Headset (or earset) mics with cardioid capsules would be the best for avoiding feedback. Omni capsules usually sound better and can be used in many live sound system environments as well. H/H mics work, but I would avoid them with inexperienced presenters.

I did a lot of live panel discussions and always liked to use a mixer's pre-fader aux sends to feed the house system and the main faders for the on-the-fly recording mix.

[The Documentary Sound Guy]

If the hall and speakers are set up correctly, it should be possible, but you are right that chest-placed lavs aren't always easy to control.  You don't say how much experience with live sound you have ... can I assume you already the basics under control?  i.e. do you need to hear about speaker placement and ringing out the room?

[humbuk]

1 hour ago, The Documentary Sound Guy said:

If the hall and speakers are set up correctly, it should be possible, but you are right that chest-placed lavs aren't always easy to control.  You don't say how much experience with live sound you have ... can I assume you already the basics under control?  i.e. do you need to hear about speaker placement and ringing out the room?

I have many years of experience as a film and TV sound engineer. I have minimal experience with live hall sound. In theory, I have a rough idea of how it should look

[The Documentary Sound Guy]

Live sound is its own beast for sure.  I think if I was in your position, I'd see if the client would hire a front of house engineer to handle that side of it, and I would just focus on the record track.  This is the proper workflow IMO.  There's a lot to think about if you are already handling a broadcast mix.  I'm not much more experienced than you, so hopefully this is actually helpful, but off the top of my head, here's some additional equipment / things to consider:

• 31-band EQ to ring-out the room, and enough time in sound check with no one else in the room to properly ring out the room for feedback.  If possible, find a way to practice this process so you aren't doing it for the first time on the day.
• Single-purpose "feedback killer" on the live outputs (There are boxes that do this, I don't know much about them other than that they exist).
• Consider using an automixer (probably Dugan) that can automatically keep unused channels down for speakers who aren't talking (this will help with bleed and also very good for maximizing signal to noise for feedback purposes).  At the very least, bring unused faders down a bit if you can predict who is speaking and when.
• Keep monitors at the front of the stage, facing away from the panelists / performers (you already know this).
• If it's a large discussion and the channel count gets high, a headset (to bring the mic closer to the source) or a cardioid lav will both improve SNR and therefore gain-before-feedback.