Camera Sound

[shuggs]

I'm looking for something to sort out my camera feed. I'm looking for a piece of rackmountable kit that will prevent any buzz and limit or compress the audio that I'm sending to my cameras. I'm getting fed up of constantly monitoring my own camera feed when theres not an editor on site can anyone help?

 

Thanx

[Ben Langfeld]

What are you trying to achieve with such a device? If you could expand on the way you have your existing gear setup and what you're trying to accomplish, it would be easier for people to make a recommendation. :) Oh, and welcome to the BlueRoom.

[shuggs]

What are you trying to achieve with such a device? If you could expand on the way you have your existing gear setup and what you're trying to accomplish, it would be easier for people to make a recommendation. :) Oh, and welcome to the BlueRoom.

 

 

Sorry, was kind of looking for an easy answer to jump out at me I've been searching the interweb looking at possilbly seperate compression and maybe a d.I with an earth lift.

 

I'm sending an aux feed from my allen&heath to cameras on corporate gigs, conferences and awards, etc. When the footage goes into the studio for edit the audio is sometimes clipping and occasionally dirty. I try to monitor it during the show with the aux afl but cant all the time. I also try to ask camera operators to monitor it but they often dont! ( whos job is it?!)

 

I was hoping there might be a single piece of kit that limits the feed stopping possible clipping and also something that would lift the earth to stop buzzing.

 

Thanks :blink:

[Ben Langfeld]

Just an average compressor/limiter and a DI would do, but you say you send audio to cameras - is this one camera or multiple? Could you not use a HD recorder at the desk, and do away with an extra cable feeding to your cameras, and leaving the responsibility for the audio recording with the sound crew?

[Rob_Beech]

To start with, its a job that should be sorted out before the show or conference starts its therefore not one persons specific job, I know this if often tricky. With the correct gain structure there should be no chance of clipping. You can create a signal lead that lifts the ground at one end if you are using balanced connections for you input although normally there should be no need for this if things are setup properly.

 

As for dynamics, you could send the aux through a compressor first to tame the peaks a little and reduce the dynamic range. For music a multiband compressor may be of beneift, theres a recent topic here about them although its mainly based around using them live.

 

Remember, if you have a ground "hum" on a signal then there is something wrong, lifting a ground is only masking the problem not solving it (and sometimes it doesn't even do that). Its much better to stop it happening rather than to try and get rid of it further down the signal chain.

 

Also, remember that a signal may sound fine at the AFL on the desk, but with poor gain structure and incorrect use of cables and the like it will sound worse by the time it gets to the camera.

 

 

Rob

[shuggs]

Yeh I already record into sound forge for backup but it just takes more studio time post show. I've got and sqn kit that I use for outside broadcast but this obviously needs to be monitored constantly which I cant afford to do during a live show with cues to fire. I was hoping there might be single piece of equipment that I could send the camera feed through to take care of it for me.

 

Was looking at something like an LA Audio MPX10, has anyone used one?

[GreatBigHippy]

A few notes:

root is quite right, the way to do this "correctly" is to record to a HD unit (or similar, I use a mac with logic running) to record too. I will say that if you sync everything together properly then post production should be a case of drag and drop.

I might make a suggestion on the hum, although I may be doing the whole sucking eggs lesson here. Do you have your cameras plugged into the mains whilst recording? I only ask as most of this type of kit isn't earthed and so can cause some serious hums when connected via audio cables. If it is, just try running off batteries and see if it makes a difference.

Secondly, are you sure its clipping at the desk outputs? Maybe the signal is too hot for the camera? try a DI box with a 20dB pad on it, see if that helps. Long shot.... but you never know, I only say as you mention you record into soundforge and don't mention clipping problems there.

The MPX10 looks like overkill to me. Thats a channel strip, not a limiter. You are recording from desk outputs so don't need preamps.

Your last option (if the clipping problem exists in soundforge) is to record at a higher bitrate. get yourself a £50 soundcard, emu do good external ones, although m-audio are easier to get going with. Set the bitrate to 24bit 96Khz and halve your recording volume. The higher bitrate means much better resolution and thus you will be able to normalise this signal and not notice much, if any signal degradation.

Lastly, have a look at your power set up. With the exception of your amps, it sounds like all of your equipment would easily run off one 13amp socket (CHECK THIS FIRST!), as mine does. This can minimise any problems with ground loops by ensuring all of your kit shares a common ground.

Anyways. Hope that helps, stay around on the boards and let us know how it goes!

Cheers,

theHippy

[mackerr]

A few notes:

root is quite right, the way to do this "correctly" is to record to a HD unit (or similar, I use a mac with logic running) to record too. I will say that if you sync everything together properly then post production should be a case of drag and drop.

How is this the "correct" way? It is of no use at all to someone who is taking the tapes and doing an analog AB roll edit. It is also of no use if the tapes are archival and will have no post at all. For most uses recording sound on the video tapes is fine, and is the most straight forward solution for any edit scenario. The problem seems to be that the OP is getting bad results at the camera. Are you recording a zero tone at the top of the first tape? How are you setting the level between the desk and the recorder? Is the recorder just a camcorder, or a separate video deck? If the camera is something like Betacam it likely has both mic and line input, although they may be on the same connector. Is the input set for mic while you are sending line?

 

If you set the level with tone before you start, you can watch the level on your desk and know what is happening at the recorder. If you want to insert a limiter or compressor on the feed, it should be in an insert so you can still see the level. If you are sending to multiple recorders you may also want a DA to split the feed to as many decks as you have. If you are using an aux send as your feed in conference situations, I find that setting the aux send level for your playback devices 3 or 4dB lower than for your mics helps. I often find the client wants their video playback really rockin', so having it a little lower in the record feed helps.

 

Mac

 

edited to add "playback devices" like I originally intended

[paulears]

Before we delve too deeply, a few bits are missing.

 

What are the cameras?

 

Assuming they are the type typically used for conference work then they'll usually have balanced audio ins, in stereo and have switchable line/mic levels. Most have pretty good limiters and can cope with quite large level changes. I certainly don't have the kind of problems the OP talking about.

 

Mine are very happy with even a rough set aux output - the noise floor being low enough to cope with too little, and the limiter gentle enough to not allow clipping but allow a bit of 'life'. The odd occasion I've had hum issues, an XLR barrel with earth lifted fixed it straght away.

 

I'm wondering if you are doing it with pro-sumer camcorders with only unbalanced, mic level inputs - getting a converter to cope with proper inputs is probably the most common way. Many of these types of kit have pretty unforgiving level matching, and quite poor monitoring.

 

You asked who's job it is to set levels at the camera? The op - always. Even when working with a separate recordist, the level setting on the camera gets done by the cameraman.

 

One comment - if it's conference work and you are multi-cam'ing it afterwards, I've always used the audio from just one camera, not switching the audio at all. Sync wise, the waveform displays from the other cameras allow you to tweak sync, but I rarely mess around with attempting to match audio - especially if the cameras are different. matching my JVCs against Sonys is just about possible video wise, but the Sonys sound very different.

 

For what it's worth I usually record room sound on one audio track on each 'B' camera, and stereo with no room, onto the master camera. Best of both worlds then!

[GreatBigHippy]

How is this the "correct" way?

OK. I'm big enough to admit mistakes! Poor, poor wording, I can do significantly better than that!

I clearly haven't had the experience that you have had, haven't had time yet :) but I'm getting there and learning.

It seems that, as mackerr and paulears have pointed out, more information is required. I'm afraid I only offer my opinion based on what I see.

I'll wait a little next time, and pick my wording more carefully!

Sorry,

theHippy

[Bobbsy]

At the risk of making a "me too" post, I'll agree with paulears on a couple of things here.

 

First, unless you have the facility to record matching timecode on all cameras plus the hard disk recorder (and sync to this in editing) us of a HD is probably not the best way to go. Over on the Adobe Premier Pro/Audition forums we have almost daily queries from people who try this and have problems with drifting sync.

 

Second, I also have my suspicions that the OP may be plugging a line level aux feed into a mic level prosumer camera input. If this is the case, then the first order of business (short of buying professional cameras) is to drop the line level output to mic level. A google search should bring up various devices to do this, though I've never used them myself.

 

Bob

[dunk_1984]

2 options, depending on budget and cameras, the first is to keep feeding to cameras.

 

Alternatively buy as previously suggested a HD recorder or a DV recorder like these : http://globalmediapro.com/do/category/vtrs

 

and these would allow video feed from cameras, and a matrix aux feed, or however you output, so you combine them on the seperate unit, but then again this requires all the video cable to link camera to vtr.

 

Unless your camera has a balanced/ some unbalanced XLR's will take it, the inputs (especially jack) will clip/peak/ distort over distace very easily, therefore unless you have a proper input... these will not improve on board the camera. therefore if the money is there, then get a vtr, and hook mixer, and camera into the unit and there you have synced sound and video.

 

I think this may have been said before, but I hope this helps more, or re-enforce previously mentioned points.

[dbuckley]

This is one of those occasions when a flashy compressor may be a better bet than something more standard, a compellor f'rinstance...

[Bobbsy]

Unless your camera has a balanced/ some unbalanced XLR's will take it, the inputs (especially jack) will clip/peak/ distort over distace very easily,

 

Er, I'm not sure about your reference to an "unbalanced XLR". I guess this is theoretically possible, but I can't thing why anybody would use an XLRconnector for an unbalanced input. Also, in practical terms distance has nothing to do with clipping or peak distortion. It makes you more prone to noise on an unbalanced circuit. As has been said, it's rather more likely that a line level source is being fed to a mic level input. This never works well; impedences are mis-matched and, even if you reduce the output level of the Aux, your taking your source down into the non-linear part of the range where a small jump in level can make a big difference.

 

Bob

[dunk_1984]

Yes sorry, the cheaper cameras that put XLR's are often unblalanced and have some difficulties without a powered mic. and yes, especially 3.5mm jack mic inputs these are very prone to noise.

Sorry for confusion.