Field mixing tips regarding noise and good levels.

[Clint Nitkiewiz Hernandez]

Okay, so my sound mixer guy does not know what he is doing, I am the one doing the research for him to see how to do stuff, and well, I really want everything to be good so.

1. If I buy a good pair of headphones, say the industry standard for $100, he should be concerned more with the levels on the mixer, or with the noise in the headphones, or both?

2. As an editor I know that headphones drastically increase the noise heard in an edit. Though that same footage played on calibrated monitors returns no noise. Headphones just tend to do this, even a slight bit. So should he aim at getting rid of allllllll the noise in the headphones, or will there always be an okay amount, especially if all levels look good? Because as an editor, there is a small amount of noise that is okay, so just wondering for field mixing if this applies as well, or is the goal of a field mixer to remove all noise, even the noise that would be okay as an editor, because less is better correct, if quality and gain is not affected.

 

[10s]

1st off you need a sound person that is interested. If he's that careless then you're in trouble unless you just want to have fun.

You want good levels averaging around -20dBFS, with peaks at -12dBFS, and of course you want very low to none, noise.

Some headphone amp/circuts aren't too clean so you get noise; it can be difficult to judge your real audio signal to noise ratio.

Test all audio components and the entire audio chain [from capture to DVD playback] weeks [better to have a few months] before you shoot so you can learn everything, develop skill, solve problems, and know what the end result will be with confidence. Too often a film project is the learning scratch pad people learn on rather than doing it correctly and properly.

 

[ullanta]

Not 100% sure what you mean by "noise". Meters don't tell you anything about noise, just about sound levels.

As 10s said, you need to spend significant time learning your equipment. Learn what your headphones and headphone amp sound like. Decent quality headphone amps should not be making noise. There's nothing about headphones that make them "noisy", and they shouldn't be noisier than speakers.

Once you know your equipment well, and know what noise may be inherent and unavoidable in each component, THEN you can think about reducing situation-specific noise.

By definition, no amount of noise is "OK". Noise is UNWANTED sound. If there's a way to avoid or minimize it, you should always do it.

Once you decide on your equipment, you'll have some other decisions and issues. I wouldn't take 10s's recommendation for -20/-12 levels if you end up using the camera as a recording device... I find the HVX is a bit too noisy at those levels... if you have a decent 24-bit recorder (e.g., your Fostex), then they're reasonable.

 

[10s]

OK,OK, OK, set it to peak at -6dBFS, & average at -14dBFS. On the HVX that'll equate to around what, 65 to 80% on the meter? That should be hot enough.

Also, the Limiter (ALC) should be ON!



..............and get a dedicated sound guy............

 

[Steve House]

OK,OK, OK, set it to peak at -6dBFS, & average at -14dBFS. On the HVX that'll equate to around what, 65 to 80% on the meter? That should be hot enough.

Also, the Limiter (ALC) should be ON!



..............and get a dedicated sound guy............

ALC (Automatic Level Control) and a limiter are not the same thing. ALC rides gain all the time, boosting it when it's quiet and cutting it back when it gets loud. A proper limiter doesn't do anything at all to the gain when it's quiet and keeps out of the way as it gets louder until the signal hits its threshold, then kicks in to keep it from going higher.

 

[ullanta]

Steve: ALC (on the HVX/DVX, at least) IS a limiter, not an AGC.

 

[SonicStates]

I would keep the ALC off and make sure you have a decent sound guy (a sound guy interested in doing his/her own research....sheesh!).
In the end, it is just so much better to record to an external unit when compared with recording direct to the HVX...Oh and not enough good things can be said about learning your gear. If you want to waste your time and that of your crew then go ahead and learn on set. It will choke your workflow and guarantee a very irate team.
All the best.
Sam

 

[saneproductions]

The ALC should be turned off on a DVX/HVX if you are using a mixer. The limiters on an SD302 are much better/smoother and will be much less noticeable when you hit them (which you should try to avoid) than the in-camera ones. If someone has a lot of dynamic range in their voice, recording average levels that are hot enough can require "kissing" the limiters occasionally on a strong word or laugh.