At a wedding we filmed today, it appears that we received terrible feedback from the DJ's equipment on the Panansonic HMC 150. We had to turn off the audio on my husband's HMC and only use the audio from my Canon 60D for the second half of the wedding, or else it would have echoed feedback all afternoon long. How do you get around this issue, for future reference?
Feedback is where YOU are supplying the sound that you are then recording, resulting in a major howling noise. I doubt you were feeding the DJ's system with audio from the HMC, so "feedback" is probably the wrong term here? So, for the sake of discussion, I'm going to assume you mean too much sound (loud) and/or simply an echo from a DJ system during speeches? Anything else and you should have been able to adjust the audio levels on the HMC input using the dials.
DJ Equipment is certainly problematic at times. When ever the couple spring a PA system on me without notice I KNOW I'm going to have problems with audio. One of the questions I always ask both at the time of booking and again a couple of weeks before is whether they are using a PA system for speeches etc. Usually the answer is no and I place wireless mics on the table in front of the speakers to capture sound while I film from the back. If they say yes then I try very hard to get a direct feed from the PA system in to a portable recorder so that I get the mic feed and not some echo around the room from the speakers. Worst case I place an audio recorder immediately in front of the DJ's speaker cabinet to capture that instead.
You can never have enough audio options!
Where you can't capture usings a direct feed (i.e. record out) from the DJ's board and you can't get a mic in from of the DJ's Speaker Cabinet it has to be recorded live in the room and fixed in post instead (when I say fixed, I mean the effects are minimised using EQ etc). Of course the opposite happens too. You're all wired up to the PA system and some smart father of the bride thinks he doesn't need the PA and now no one further back than the front row can hear him, but he's not going to use the mic regardless of what anyone says! So, as almost no one can hear him, they start to whisper, then talk quietly amongst themselves so the room noise gradually increases and you have even less chance of hearing him, so yet more people start talking amongst themselves and it's all down hill from there! You start hearing people going Shhhhh!! which does nothing but mask the speaker even more!
So, mics close to the sound where possible, plug-in to the PA system where possible and record open mic from the cameras too. 3 Sources should generally cover you in post, but the more options you have the better.
So, for the "echo", just how bad was it? Can you slip the audio a frame or two in post?
Echo is often the result of booming bass frequencies, so add an EQ to the audio and turn down the bass and increase the treble frequencies a little. You may not like the sound as much, but it generally makes things easier to hear.
