FORUMS: list search recent posts

Hiss betwee=n mics, mixer and camera

COW Forums : Audio Professionals

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
Steve Alsip
Hiss betwee=n mics, mixer and camera
on Nov 9, 2010 at 2:36:50 pm

How do I hook up multiple mics to a mixer and output to two cameras with out getting a hissing noise? There is line noise coming in although I can hear the audio. Tried switching to line and not getting a hot enough signal.

Axden Mic
Sure Shotgun sm89

Mackie CFX12

Panasonic AG-HPX300
Canon 5d


Return to posts index

Bob Kessler
Re: Hiss between mics, mixer and camera
on Nov 9, 2010 at 5:23:26 pm

Okay...

The Mackie is not a production sound mixer, it is intended for mixing music; it will have (comparatively) quite a bit of self noise. That being said, there are a bunch of other things that you should check.

1. Only the channel(s) that has a sound source you want to record should be engaged, all of the others should have their faders all the way down and the "mute" button engaged. An open channel will generate hiss.

2. Do not use any EQ on the channels except perhaps a little bass roll-off. You can EQ in audio post, and anything done to the signal in the field cannot be undone later.

3. Do not use the master graphic EQ.

4. Make sure that all of the aux sends/returns are off.

5. Make sure that the effects sends/returns are completely disengaged.

I assume that you meant an Azden mic. Azden products have very poor self-noise characteristics, meaning that the mic generates hiss all by itself. The Shure is an decent mic.

No matter what there is going to be noise with the gear that you are using. What you have to learn is gain-staging; that is getting the optimum signal with a minimum of noise; that includes the audio settings on the camera. Take your time and figure out the optimum settings for your collection of equipment.

I would suggest that you may get a better signal by plugging the mic directly into the camera or getting a proper production sound mixer.


Return to posts index


Bill Davis
Re: Hiss betwee=n mics, mixer and camera
on Nov 9, 2010 at 8:05:19 pm

Good info in the other post, but in THIS case, I suspect your problem is at the very end of your audio chain.

The 5dMkii audio input has an AGC (auto gain control) circuit that pumps up the volume automatically in an attempt to amplify low sounds. It's typical in these circuits for the NOISE FLOOR (hiss) to come up dramatically when no other signal is present. There are outboard devices that try to defeat this AGC problem by presenting the mic input with a sub-sonic TONE at a constant level to knock down the AGC - but IMO these are at best, work arounds.

THIS is a primary reason most people use DOUBLE SYSTEM SOUND when recording video to a 5dMkII.

Your HPX-300 OTOH, has balanced audio ins via XLR. Record ALL your sound there - and simply use the 5DMkii's audio as a sync track for post.

If you're getting hiss from one of your mics on BOTH cameras - the first place to check is if the mic needs phantom power. Mics that require it - but don't get it - typically hiss like snakes.

Good luck.



Return to posts index


Steve Alsip
Re: Hiss betwee=n mics, mixer and camera
on Nov 10, 2010 at 2:29:52 pm

Hey Bill ... thanks for the reply. I ended up going directly to the Panisonic for sound as planned and will sync in post. However. Do you have a suggestion for a production setup? Perhaps a 4 - 6 channel field mixer? And what else I can use to set up amd use it properly amoung 2 - 3 cameras?

I have an attenuator. Think that would help with the 5D?


Return to posts index

Bill Davis
Re: Hiss betwee=n mics, mixer and camera
on Nov 10, 2010 at 8:00:50 pm

Steve,

The truth is that sound recording is actually a very complex undertaking.

It starts with asking "what am I recording" and it continues to jump through hoops and try to avoid pitfalls up to the second huge question which is "What kind of recording do I need and where and how will I use it?"

Let's make it simple and say you're recording a singing trio. You could set up a single mic in the middle of all three and get a recording of the group sound. OR you could set up 2 mics, use one for the lead singer and the other for 2 backup singers and have control over the BALANCE between the lead and the backup vocals. OR you could mic each singer individually and post mix the balance of everyone to taste.

Each of those approaches gives you different options, requires different complexities of setup - and employs a different arrange of equipment.

Extrapolate that to what might be needed to record a 5 piece rock band with 2 singers and you get a HUGE range of approaches. Which one is best depends on budget, time, expertise, and the required results. And there's NO single correct answer.

I can't even BEGIN to answer your questions because I have no clue what you're doing - what budget or resources you have at your disposal or what final result you want.

If you want to take the time to plot all that out and then ask me for some ideas about the SPECIFIC situation you'll be facing, I'll be happy to do so. But there's simply no way to make blanket advice that fits all situations.

Sorry.



Return to posts index

Craig Alan
Re: Hiss betwee=n mics, mixer and camera
on Nov 11, 2010 at 2:57:40 pm

http://www.bhphotovideo.com/c/search?Ntt=sound+devices+552&N=0&InitialSearc...

OSX 10.5.7; MAC Book PRO (EARLY 2008); Camcorders: Sony Z7U, Canon HV30, Sony vx2000/PD170, Canon xl2; Pana, Sony, and Canon consumer cams; FCP certified; write professionally for a variety of media; teach video production in L.A.


Return to posts index


Steve Alsip
Re: Hiss betwee=n mics, mixer and camera
on Nov 11, 2010 at 9:42:21 pm

I just ordered a FP33. Will that do the trick? Two of them in fact.


Return to posts index

Bill Davis
Re: Hiss betwee=n mics, mixer and camera
on Nov 11, 2010 at 11:39:19 pm

Absolutely.

Take three mics into the FP-33 and set their gain to taste. Then output ALL of them to a single channel Right or Left - use that to FEED one channel of your camera XLR balanced audio input.

Then do the exact same thing with the second FP-33 - outputting that mixer in MONO to the OTHER channel on your camera.

Bingo - up to six tracks of audio mixed onto two tracks of your camera master - ready to go to post.

You won't be able to RE-mix things - but if you pay attention to your settings and use the mixer's limiters properly, there's no reason you can't get a clear recording of all six mics with this setup.

Good, solid, professional choice.



Return to posts index

Craig Alan
Re: Hiss betwee=n mics, mixer and camera
on Nov 12, 2010 at 3:04:22 am

sound devices have better sound and features and the link I gave you was for both a mixer and recorder since double system was mentioned due to poor audio of canon 5d. If you just want mixer(s), I'd go with 2 of the sound devices 302s. Do a search for fp33 vs sd302. You'll see what I mean.

OSX 10.5.7; MAC Book PRO (EARLY 2008); Camcorders: Sony Z7U, Canon HV30, Sony vx2000/PD170, Canon xl2; Pana, Sony, and Canon consumer cams; FCP certified; write professionally for a variety of media; teach video production in L.A.


Return to posts index


Bill Davis
Re: Hiss betwee=n mics, mixer and camera
on Nov 12, 2010 at 8:57:17 am

The OP indicated they'll be recording to the stereo XLRs of a Panasonic Video Camera.

That tells me that they don't need theatrically pristine sound - just solid professional performance.

You can COMMONLY find Fp-33s on Ebay at around $500.

You hardly EVER see Sound Devices stuff on Ebay (outside the MixPre which is the lowest end they sell). By the way, I think the primary reason for this is that SD is a VERY much younger company than Shure and there is very little of it's merchandise in the used channel - where Shure - having been a player for decades has a VERY strong presence.

The OP also indicated that he's not in the sound business particularly - but wishing to add some sound gear to his general practice. That makes me think that a solid workhorse like the Shure stuff might be a better fit than the higher quality, but more than twice as expensive Sound Devices gear.

After all, add field covers and reasonable accessories to each and we're talking 1000 to 1200 for the two Shures he needs, but 3k gets him only 5 (admittedly cleaner) channels on the SD 502 - and a pair of 302's will be significantly more expensive to get his 6 channels covered. it's a pretty significant dollar difference.

It's great to go for the best gear - but sometimes spending twice as much for that top 10% of performance extracts a real premium that's only justified if you have the clientele IN PLACE to support it. I think this is one of those cases.

And spending in accordance with the level of your work - with an eye to the eventual depreciated value of said gear is a pretty smart thing, IMO.

YMMV.



Return to posts index

Craig Alan
Re: Hiss betwee=n mics, mixer and camera
on Nov 12, 2010 at 2:19:51 pm

You make some good points. Here’s a counter: I used the fp33 a lot for a couple of years. One of the channels went bad. It’s a rugged unit but stuff can go bad. I would not buy used. The 302 retails for the same price and the fp33 came down in price due to the sd302. The 302 has cleaner sound, is smaller, better built, and designed. The fp33 eat batteries at a pretty good clip. The 302 has more control of output limits. It has better meters. I’d rather have cleaner audio than a slightly better picture for most shots. The 302 will keeps it value better.

OSX 10.5.7; MAC Book PRO (EARLY 2008); Camcorders: Sony Z7U, Canon HV30, Sony vx2000/PD170, Canon xl2; Pana, Sony, and Canon consumer cams; FCP certified; write professionally for a variety of media; teach video production in L.A.


Return to posts index

Jordan Wolf
Re: Hiss betwee=n mics, mixer and camera
on Nov 13, 2010 at 7:13:56 am

Steve,

It sounds to me like there is a gain staging problem. Put in layman's terms: something is turned up too much or not enough.

You've gotten good advice, but if you're stuck with your current setup, I have some tips:

1. Set the gain on the mixer appropriately. For your mixer, do this by having the source make noise (talk, play instrument, etc.) and turn the Gain knob until the Zero light starts blinking.

2. Set the levels on the camera appropriately. For the Panasonic, you'll want to set the levels so that the meters never "clip" and, on average, remain around "-18" to "-20". The numbers represent how much headroom, in dB, you have left until nasty noises occur.

Wolf
<><


Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2017 CreativeCOW.net All Rights Reserved
[TOP]