Clipping via house mix to camera. Need help

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offbeatbryce

Well-known member
Hello,

I filmed a concert and I hope someone here can know what my problem is.

The person operating the mixer gave me a house mix feed from the board via xlr to my camera.

At certain parts where the musician gets louder you can hear what sounds like static but only at louder parts where the vocalist sang louder. The camera input was not clipping. I had it set to -10db. The sound guy had his output at -15db the house mix also went to two speakers. No static on those speakers at all. I took my headphones to compare. What caused this? Is this room reflection? There were windows and a wood ceiling above the singer. Would it only pick it up via xlr?? If so why?? It's not true distortion because as I said neither was the mixer or my camera anywhere near 0db.

Other times it was fine bust mostly happened during duets with more than one singer at ones or guitar added.

I think I can eliminate some of it in post cause it's not horrid. But just would like to know what's causing this.


Even more strange is this is more noticeable via headphones from my camera vs playing it back in premiere. Anyone know why that would be??
 
So were you going into the camera at mic or line level?
Did you use an 'inline' pad?
Were you monitoring during the performance with headphones or just watching the audio meters?
Were you running with 'Auto level' turned on?
What sort sort of camera are / were you using?
The feed from the house PA was that a full mix out or was it an 'AUX' out or something else?
 
The clipping could easily have been happening back in the venue mixer before the audio signal ever got to you.
Without knowing what mixer board, exactly which output, which camcorder, exactly what settings, etc. it is impossible to try to debug anything.
Setting levels "by the numbers" is not effective. You MUST do a test, preferably with the actual performers to "gain stage" the entire system including the venue system and your recording gear.
Were you not monitoring the audio signal using good headphones? How did you miss the problem during the performance?
 
Sending line level into a mic level input will most certainly clip (distort), regardless of the record volume setting.

"I had it set to -10db. The sound guy had his output at -15db."
- I assume this means fader position .. not operating level. Most console outputs (XLR and 1/4") are +4dB (aside from the RCA and HP).
The 'venue mixer' could very well be the person of blame. In the non-pro events, they are often an unskilled volunteer or an equally inexperienced friend of a friend. ... Even the paid A/V staff at hotels and such, don't often know much about audio gain staging and operating levels. (however I still suspect the OP's problem is a 'line-to-mic' level issue.
 
Rick R said:
Sending line level into a mic level input will most certainly clip (distort), regardless of the record volume setting.

"I had it set to -10db. The sound guy had his output at -15db."
- I assume this means fader position .. not operating level. Most console outputs (XLR and 1/4") are +4dB (aside from the RCA and HP).
The 'venue mixer' could very well be the person of blame. In the non-pro events, they are often an unskilled volunteer or an equally inexperienced friend of a friend. ... Even the paid A/V staff at hotels and such, don't often know much about audio gain staging and operating levels. (however I still suspect the OP's problem is a 'line-to-mic' level issue.
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It was XLR from House mix out into my canon xa25. I was monitoring in headphones the whole time. I heard it when I was filming and had the sound guy listen. He couldn't figure it out. It was the same mix that came out of the PA system. It wasn't clipping during some performances but other it was even though the level on my camera didn't exceed -10db. Spekaing of Line level when I switched the Line in my camera no sound came through unless I had it switched to Mic Phantom power. Why would that be?

It only realy happened when a guitar or duet came into play. A solo singer was fine. So that is weird
 
Doesn't sound very weird to me. Sounds like the venue FOH mixer wasn't paying attention to his job. Or maybe he was inexperienced or distracted, etc. There are a dozen different things that could have caused that problem. It is quite possible that there was distortion in the venue PA system also, but not nearly as obvious to a live audience as it is after the fact in a critical monitoring/mixing environment. If you hear distortion during recording you must do something to fix it immediately. There is no second chance with a typical live performance.
 
It is probably overloading the mic amps in your camera, the level can be OK on meters but if there is too much coming in the front end it can overload the input or even the pot that is before any metering.

It could be that it was being fed at domestic -10 audio (phono/tape output) levels so too low for std line input that is expecting +4 but near to mic level but when it then peaked more it overloaded the mic amps or other components in the chain.

If you are feeding any mixer into mic inputs on a camera it is always good to put a buffer or interface box in circuit and the ones I use are made by ART:
 
Richard - I get a bit grumpy and touchy on this subject. In the venue the sound ops primary job is the show - they do not have the ability to provide a proper, monitored and level matched output. I've done this myself - the video guy suddenly arrives and asks for an output. You give him one - but often sound check time is long gone, so you guess the level, maybe play some background music, or a track at roughly show level, and then see if his meters twitch If he says OK - then that's probably the only time I would have time to listen to the feed. During the show, I'll probably see the meter and if a sensible level shows, that's it. Trouble is, gain staging and multiple sources mean that while the send to the video might be at the right level, the signal could be far too hot earlier in the chain, and you cannot see that on a meter. Maybe one of the other sources ran out of fader travel - perhaps the performer for some reason played more quietly, so the gains were tweaked - forgetting that maybe this was a prefade send to the matrix or somewhere else the video feed was sourced from. The sound op is usually being paid for the show sound. Sometimes they might be responsible for video sound, but this is rare - very rare in my own experiecne of show video.

The guys who work for me get quite grumpy at having suddenly extra responsibility for video feeds. It is NOT their job, and unless arranged in advance, it is a courtesy, a freebie, or simple grin and shut up stuff. They get even more grumpier when they get complaints that the video was spoiled by them not noticing the problem. Tough! If video people want a nice controlled mix - then provide somebody to do it. My guys would be quite happy to give a visiting video sound person a row of sends, and headphone facilities - but the video people never have anyone with them. Video people do it with the lighting people too. Sound lighting and video are three disciplines and not there to service each other. They're independent, but usually collaborative. I have in the past had sound people totally unwilling to provide audio to video people because they've been treated badly in the past. I don't blame them - when you hear the slagging off they get. For 'fun' this year, in my venue we asked every video team who showed up for a video feed from their camera for a monitor (which we have, and the cable) that the lighting operator can use to check what the images being shot are like, and perhaps assist with some mods. Out of 7, only one was happy to do it, and took our BNC and sent us the feed. The rest either said no, or gave the most ridiculous excuse. 3 cited copyright!

It seems that some video people do indeed think the world revolves around them. The guy who provided the video feed got a balanced and monitored audio feed - looked after by our A2, who was spare for that show, and I'd like to think the images we saw were pretty good.

So please - do not blame the sound op for your unpreparedness or lack of proper planning. Not ONE video company contacted me this summer before arriving, yet all needed things from us that were or could have been a problem. Some of the big acts do this perfectly. Jimmy Carr, a popular comedian - always sells out. He asks for a stereo feed of the main mix, but excluding music and sound effects, to be supplied on 2 X balanced XLRs and at no more than a specific level (can't from memory remember what it was). He asks for 13A power at specific locations and specific space for certain equipment he tours. When he arrives, everything asked for is ready, and part of the deal. If these people turned up an hour before the performance and asked for all this - they would not get it.

When you go to a venue and ask for a feed, did you remember to email the tec manager a week or so before and ask for it? Video requirements when contracted with the producer of the event will never be passed on to the venue unless you do it yourself - unless the client is an experienced producer, and most are not.

Sorry - rant over, but this really annoys me - sound - the bad uncaring profession, letting the poor video people sink.
 
Paul, that sounds spot on.

I had an audio feed from the mixer at an event last week. Due to the organisation (lack of) no one knew who or what was going on. I was doing the video but discovered a set up very different to the one I was expecting. The Audio and lighting teams had no idea there was going to be a video person there. (also the venue were not as helpful as they could have been so everyone was running late). I got a feed from the mixing desk and had similar problems to the OP in one or two places. Part way through I got some minor clipping even though my levels looked good.

Also after the mixing desk unexpectedly discovered that they were being moved 1/2 way through the event during a break to go from conference to dinner layout. I also had to move (20 feet vertically) I lost the audio feed. The man on the mixing desk was freelance and had stepped to help. He was using a desk he was not used to. (smallish desk with a screen & layers of SW menus rather than a big desk with discreet sliders and knobs. The SW reset my feed when being moved as it was not part of the planned set:-( )

I got my feed back with out too much messing about but both the audio person and I could have done without it. As you say their job was the sound not baby-sitting me.

As for a feed from my video. I would not have a problem with that.

BTW I can't see how copyright would come in for the video any more than it would for the audio..... a double edged sword saying that. Don't give them the [copyright] audio feed next time :-)
 
In a small community theatre I was doing some work in for awhile I actually put in an audio feed (XLR), power and a level platform for a tripod to be nice to videographers, despite all that most of them couldn't get it right. They expected me to have the 'correct' adaptors to fit 'THEIR' camera / s.
You are right video people turn up with only minutes to spare and then complain when you don't attend to their every need......
 
@paulears, I did not intend to cast blame on the FOH guy. To be sure I have frequently at different times been on BOTH sides of that situation. And I agree 200% that it is NOT the job of the FOH guy to in any way provide a proper "recording mix" for the videographer or anybody else. Unless that has been work out and agreed to by prior arrangement. I suspect that @offbeatbryce doesn't realize what a can of worms he has opened here. This is a far more complex problem than imagined in the casual anecdote that @offbeatbryce recounted here. I have more sympathy for the FOH guy than for @offbeatbryce who seemed unprepared and inexperienced in dealing with this situation.
 
Hello

Hello

Richard Crowley said:
@paulears, I did not intend to cast blame on the FOH guy. To be sure I have frequently at different times been on BOTH sides of that situation. And I agree 200% that it is NOT the job of the FOH guy to in any way provide a proper "recording mix" for the videographer or anybody else. Unless that has been work out and agreed to by prior arrangement. I suspect that @offbeatbryce doesn't realize what a can of worms he has opened here. This is a far more complex problem than imagined in the casual anecdote that @offbeatbryce recounted here. I have more sympathy for the FOH guy than for @offbeatbryce who seemed unprepared and inexperienced in dealing with this situation.
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I don't think it's my lack of experience as I've done this countless of times without this problem. Here is what is even more weird. I imported the audio into Adobe Audition. The left channel is louder than the right even though both channels were set at even volumes. This is even more odd, when I added Adaptive Noise Reduction plugin the static/tin/echo that sounds like distortion goes away. Cleary this can't be distortion since it fixed it with the plugin.

There is also a low hum sound on the left channel only. No hum on the right. I didn't even hear this hum when recording with my headphones on. I have noise cancelling headphones. So I think I should of hear it.


So what the heck is it in the first place?
 
Well, we took your word for it that it was "distortion". Bit since we never heard a sample, perhaps you are right that it is not distortion at all. Your clues are sufficiently diverse that we can only speculate what might have happened from a wide variety of possible scenarios.

You should NEVER use "noise-cancelling" headphones when monitoring acoustic recordings! :thumbdown The problem is that the headphones CANCEL part of what you microphones are actually recording, and you are hearing a false representation of your tracks. Leave the noise-cancelling headphones for casual entertainment and cruising at 30000 ft.

At this point it would be silly for any of us to continue speculation until you share a sample of the original recorded tracks with the phenomenon, and then your repaired version. A clip is worth at least 1000 words possibly 10000.
 
paulears said:
Richard - I get a bit grumpy and touchy on this subject. ...
Sorry - rant over, but this really annoys me - sound - the bad uncaring profession, letting the poor video people sink.
Click to expand...

Been on both sides of that equation. From needing to connect and having told the venue in advance and showing up and it's a "surprise" (I think this is often the fault of the folks who were told failing to pass that info on), and many years as a FOH mixer and having folks show up at the last minute and expecting me to figure out how to connect to their gear that they apparently never looked at the manual for, have no cables or adapters or any clue at all about what they need. Even if they are together and have everything it's always a worry if you don't have time before the audience arrives to make sure they aren't going to cause some problem by hooking in.

If at all possible I won't take a feed from the mixer for a couple of reasons. First I understand their worries about having unknown gear connected to their system and often scheduling, union rules etc. don't let me come in early enough to have everything checked out ahead of time.

And second a board feed is not generally a good feed for recording. The job of the FOH mixer is to reenforce the sound from the stage. Depending on the event that may well not include some things on stage. You don't need to mic a bagpipe! So a board feed is almost always a very unbalanced mix (for recording) and also may have some strange EQ on it to deal with funky venue acoustics. So it is often the worst choice for recording. Usually if I'm taking a board feed it is direct outs from each channel. That works fine providing everyone talks ahead of time and you have a good amount of setup time.

OP,

Saying you have done it before with out problems tells me one thing, you do not have a lot of sound experience. Not a crime, but no one with any real experience knows that every set up is a new set of issues. Even the same venue with the same board can have new issues with different shows. It's really hard to tell from your descriptions but it sounds like a bad connection to me. Jacks and plugs can get oxidized, and or tarnished, or just plain dirty. You get a funky ground connection and your feed becomes an antenna for whatever is hovering around. Or a less that solid lead can have a "clipping" like sound. That would be my suspicion.

Loose the noise canceling headphones. You are not actually monitoring your sound with them. If you really need the isolation get some noise isolating headphones instead. You will look a bit goofy with those big cans on but at least you will be hearing what you are recording.
 
I started out as a stills tog. When I moved to "video" a fews years ago it was all solid state (no tapes, let alone film) and I was given some very good advice "the audio is 60% of video" which came as a bit of a shock to a photographer. I was pushed to getting a camera (Panasonic AC90) with XLR inputs and told: you have to be a cameraman AND sound engineer! Still learning on a vertical learning curve but it's true. For one man outfits, ENG, Corporate videos etc you are both the sound and vision guy.

You do need a certain amount of knowledge of both. I have no idea how to use a 24 channel mixer in a studio or theatre but I am getting to grips with location mics for interviews and corporate videos. Also sound feeds and know how to work with other teams. You can't just turn up 5 minutes before for some things. Breaking news you don't usually get the option :-) But where there is are sound and lighting teams you need to be able to work with them.. Obvious really. Fortunately my background means I am used to working with multiple teams in tight spaced under pressure.

On the last bit gig as mentioned above what we got was not what any of us were expecting so the other teams had their own problems and I wasn't a priority for them.
 
Noiz2 said:
If at all possible I won't take a feed from the mixer for a couple of reasons. First I understand their worries about having unknown gear connected to their system and often scheduling, union rules etc. don't let me come in early enough to have everything checked out ahead of time.

And second a board feed is not generally a good feed for recording. The job of the FOH mixer is to reenforce the sound from the stage. Depending on the event that may well not include some things on stage. You don't need to mic a bagpipe! So a board feed is almost always a very unbalanced mix (for recording) and also may have some strange EQ on it to deal with funky venue acoustics. So it is often the worst choice for recording. Usually if I'm taking a board feed it is direct outs from each channel. That works fine providing everyone talks ahead of time and you have a good amount of setup time.
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Then what setup do you recommend I have? How do I connect into all the microphones, guitars etc without the main mixer that's there? I just cant' bring my own microphones. Having singers hold two mics is a stupid.
 
Having some small knowledge of mixing for small bands in bars, I can say, I would never take a feed from their mixer. Live recording with your own mic's is the way to go. Just set up a stereo pair near the stage. The guys over at tapersection.com are experts at this sort of thing.
 
graywolf said:
Having some small knowledge of mixing for small bands in bars, I can say, I would never take a feed from their mixer. Live recording with your own mic's is the way to go. Just set up a stereo pair near the stage. The guys over at tapersection.com are experts at this sort of thing.
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http://taperssection.com ???

Some times running your own mics is NOT a option.... do you have mic cables to cover 200 metres and up a floor? That is what I was faced with. This is assuming the audio team will let you put additional mics on the lectern. ( I had to have clear spoken voice from a speaker) As mentioned both I and the sound desk got moved 1/ way through the event.
 
jagraphics said:
http://taperssection.com ???

Some times running your own mics is NOT a option.... do you have mic cables to cover 200 metres and up a floor? That is what I was faced with. This is assuming the audio team will let you put additional mics on the lectern. ( I had to have clear spoken voice from a speaker) As mentioned both I and the sound desk got moved 1/ way through the event.
Click to expand...

That sounds like something you should ask over on JWSound. I think they will tell you, for something like that, you need 3 things. 1-A contract! 2-A 3T sound truck (probably rented). 3-A crew.

In other words, that is not something a solo guy should be getting involved in. Luckily, I am just a hobbyist.
 
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