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Old June 10th, 2007, 03:46 PM   #1
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manual audio settings.....

Hi all,

I have just recently started to use 2 wireless g2 mics during my wedding ceremonies along with a rode ntg1 shotgun mic on 2 cameras.

The main camera has the shotgun and a wireless fed into both its xlr channels and the 2nd camera has the other wireless mic.
The both cameras are used in auto audio and the main cameras audio now has an echo when mixing both channels together and a hum. I know this is due to the camera being set on auto and the camera is always trying to pick up audio on its own.

I want to ask how to set up a camera in manual mode for the 2 feeds without them getting all distorted and reduce all of this additional hum and echo when one is not doing anything?
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Old June 10th, 2007, 04:00 PM   #2
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Hi all,

I have just recently started to use 2 wireless g2 mics during my wedding ceremonies along with a rode ntg1 shotgun mic on 2 cameras.

The main camera has the shotgun and a wireless fed into both its xlr channels and the 2nd camera has the other wireless mic.
The both cameras are used in auto audio and the main cameras audio now has an echo when mixing both channels together and a hum. I know this is due to the camera being set on auto and the camera is always trying to pick up audio on its own.

I want to ask how to set up a camera in manual mode for the 2 feeds without them getting all distorted and reduce all of this additional hum and echo when one is not doing anything?
Different cameras have different ways of switching between manual and auto audio level control. Indeed, not all cameras even HAVE the ability to switch to manual control. Since you didn't tell us what cameras you're using, your question is impossible to answer. I hate to say RTFM but in this case you'll find your answer in your owner's manual.

The echo or reverb is likely due to the arrival time difference of a sound at the wireless mic on the subject and the shotgun mic on the camera. Sound travels at about 1 foot per millisecond. If your camera is 30 feet away, the same sound is picked up by the shotgun mic 30 milliseconds later than it is heard by the wireless and that's more than enough for it be audible - indeed, that would be approximately one full video frame out of sync. Ditch the shotgun track - IMHO for anything other than room ambience, the sound picked up by a shotgun at the camera position is going to be so marginal as to be unusable anyway.
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Old June 11th, 2007, 02:06 AM   #3
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Thanks Steve,

I know how to turn the audio onto manual, thats no problem, but how to judge the levels so I wont be turning them up and down on the shoot, if I spoke into the mics normally and I kept the levels half way would this be enough?

It also make sense what you say about the sound distance Steve, but during a ceremony the congregation answers the priest and their is always music.

Do I just keep adjusting this in post mixing between both channels and the other cameras audio?
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Old June 11th, 2007, 05:59 AM   #4
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Thanks Steve,

I know how to turn the audio onto manual, thats no problem, but how to judge the levels so I wont be turning them up and down on the shoot, if I spoke into the mics normally and I kept the levels half way would this be enough?

It also make sense what you say about the sound distance Steve, but during a ceremony the congregation answers the priest and their is always music.

Do I just keep adjusting this in post mixing between both channels and the other cameras audio?
Does your camera have audio recording meters? In a quiet room turn on auto level and have someone speak normally towards the camera lens from about three feet in front of the camera while you observe where the system wants to put the sound on the meters. It'll probably be somewhere around -12 to -8 dBFS. That tells you what the system's designers considered to be a "normal" recording level. Set your manual levels so sounds during the ceremony are about the same. If the camera has a limiter on the audio input, engage it so sudden loud sounds don't drive it into clipping.

There's no way you can violate the laws of physics in the arrival time issue, but there are several techniques to use to minimize its effects. You have a stereo audio track synced to picture but only one of the two channels is actually in correct sync, the other is a trifle late. You'll need to take the single stereo audio track and split it into two separate mono tracks in your editor so you can deal with each one separately (Your final mixdown will still end up stereo.) You can then slip the late channel forward into correct sync - set playback to loop in a region and pull the late track up until the echo disappears.. Of course, if the delay is varying because subject movement is changing their distance to the camera, you may find that the amount of correction needed on one part of the track is different from the amount of correction on another - be alert to that and check at a number of places to insure everything matches up. Alternately, again in your editor, mute each of the channels in turn as the desired sound moves from one channel to the other - not a bad idea to do this anyway in any multiple mic situation. At any given time only one mic should be live if they're situated so that the same sound could be picked up be several mics spaced some distance apart. Celebrant or B&G is speaking, mute the shotgun channel. Audience is responding or music is playing, mute or dip the level on the wireless. At any given point in time, only one track should be up. Hopefully you will have remembered to have recorded some room tone, the room's "sound of silence," to replace the audio in the muted track rather than just having it go dead. If you don't have any specifically recorded, grab some from a lull in the proceeding while you were rolling and use it to fill the gaps.
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Old June 11th, 2007, 01:27 PM   #5
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[QUOTE=Paul Gallagher;694943]Hi all,

. . . all of this additional hum QUOTE]

You might know this but it burned me on more than 1 occasion. If the lav cord crosses or especially touches the antenna on the bodypack, you will get a loud hum as well.

Jeff
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Old June 11th, 2007, 02:40 PM   #6
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Does your camera have audio recording meters? In a quiet room turn on auto level and have someone speak normally towards the camera lens from about three feet in front of the camera while you observe where the system wants to put the sound on the meters. It'll probably be somewhere around -12 to -8 dBFS. That tells you what the system's designers considered to be a "normal" recording level. Set your manual levels so sounds during the ceremony are about the same. If the camera has a limiter on the audio input, engage it so sudden loud sounds don't drive it into clipping.

There's no way you can violate the laws of physics in the arrival time issue, but there are several techniques to use to minimize its effects. You have a stereo audio track synced to picture but only one of the two channels is actually in correct sync, the other is a trifle late. You'll need to take the single stereo audio track and split it into two separate mono tracks in your editor so you can deal with each one separately (Your final mixdown will still end up stereo.) You can then slip the late channel forward into correct sync - set playback to loop in a region and pull the late track up until the echo disappears.. Of course, if the delay is varying because subject movement is changing their distance to the camera, you may find that the amount of correction needed on one part of the track is different from the amount of correction on another - be alert to that and check at a number of places to insure everything matches up. Alternately, again in your editor, mute each of the channels in turn as the desired sound moves from one channel to the other - not a bad idea to do this anyway in any multiple mic situation. At any given time only one mic should be live if they're situated so that the same sound could be picked up be several mics spaced some distance apart. Celebrant or B&G is speaking, mute the shotgun channel. Audience is responding or music is playing, mute or dip the level on the wireless. At any given point in time, only one track should be up. Hopefully you will have remembered to have recorded some room tone, the room's "sound of silence," to replace the audio in the muted track rather than just having it go dead. If you don't have any specifically recorded, grab some from a lull in the proceeding while you were rolling and use it to fill the gaps.
Thanks Steve, I tried that with moving the shotgun mic forward a bit but when I moved in close for the vows like you said it was of sync and at different time the congregation answered, this was fine but when the soloist started at the other end of the church this was out as well.

What seems to work best and I'm getting a bit too dramatic on this subject now as this ceremony is taking far to long for my liking is its best to keep the 2 tracks as they are and just bring the 2 different lav mics up as needed. I just used the shot guns sound turned down -5 on the timeline normally and brought it up for the soloist, this sounds most natural but if I had have recorded some ambient noise like you suggested this would have been a good filler on the timeline but with weddings you just don't have the time.

Overall the sound quality of the mics is an unbelievable improvement over the shot gun on its own. I have another wedding now of Friday in a cathederal in Co. Monaghan so I will try out the sound in my local church i the manual settings and see how it turns out before then.

Thanks again for your helpful response.

Paul
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Old June 11th, 2007, 03:19 PM   #7
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... but if I had have recorded some ambient noise like you suggested this would have been a good filler on the timeline but with weddings you just don't have the time.
...
If you don't have a segment of room tone you can borrow it from silences. Find a spot where the audience is waiting for something in the ceremony and there's no dialog, coughing, babys crying, etc, Copy those seconds of audio and paste them into their own track(s), repeating them like a music loop to form a continuous track. When you want to silence one of the mics because it's picking up sound that's actually being recorded on another mic, replace the regular recording with a piece of looped ambience the same length. If your shotgun is picking up the delayed copy of sound whose recording off the wireless is the one you're going to use, replace the shotgun track with ambience for that length of time. If possible do it with each mic since each mic has its own timbre and thus each one's 'silence' will have a different quality. Using these cloned pieces of ambience to replace the sound on the mics when the sound of interest is on another one rather than just cutting the unused tracks down to silence will fill the unatural hole the complete absence of anything would otherwise leave.
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Old June 11th, 2007, 04:17 PM   #8
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If you don't have a segment of room tone you can borrow it from silences. Find a spot where the audience is waiting for something in the ceremony and there's no dialog, coughing, babys crying, etc, Copy those seconds of audio and paste them into their own track(s), repeating them like a music loop to form a continuous track. When you want to silence one of the mics because it's picking up sound that's actually being recorded on another mic, replace the regular recording with a piece of looped ambience the same length. If your shotgun is picking up the delayed copy of sound whose recording off the wireless is the one you're going to use, replace the shotgun track with ambience for that length of time. If possible do it with each mic since each mic has its own timbre and thus each one's 'silence' will have a different quality. Using these cloned pieces of ambience to replace the sound on the mics when the sound of interest is on another one rather than just cutting the unused tracks down to silence will fill the unatural hole the complete absence of anything would otherwise leave.
Thats a good idea Steve, I'll try that out. Do you use the manual audio settings on your camera, or just keep all on auto?
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Old June 11th, 2007, 04:51 PM   #9
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Thats a good idea Steve, I'll try that out. Do you use the manual audio settings on your camera, or just keep all on auto?
I don't have my own camera yet but I can think of very few professional shooting situations where you should ever use auto level control if you have a choice in the matter - IMHO that's a tool of last resort .
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