noise floor question about recording

D

deleuze3

Well-known member
is it better to
1) record a voice who is too quiet but with a low noise floor (and normalize the audio in post-production)?
OR is it better to
2) boost the recording volume of the voice (in order to normalize it) even though the noise floor will get louder..

Thanks in advance,
Julien
 
The noise floor of a recorder or camera isn't going to change so you want to put a very loud signal from the mic so the noise floor is very quiet in comparison.

If the audio is very quiet and just a little bit above the noise floor of the camera now if you boosted the audio up later the noise is going to get louder right along with the microphone.

So you want to send a nice hot signal to the recorder/camera.

EX: If your recorder noise floor is at a 2 and you record your audio at a 3. Later if you need to boost it the noise is almost as loud as the signal.
If your noise floor is a 2 and you record your audio at an 8 the noise floor will be so low you wont really hear it and if you boost it, it will remain at the same ratio.


If the noise floor you're hearing is from the MICROPHONE, that noise floor is going to get louder as you turn the volume up
but whether you record it extremely low, or extremely loud its always going to be the same % compared to the actual audio.

Say your microphone is recording a voice and getting a signal of 100.
The noise floor of the microphone is at 20.

Whether you record quiet to the recorder or loud, its always going to be a 100/20 ratio
BUT if you record quiet now you're going to hear more noise from the camera.


Short answer, record with a microphone that has a decently low noise floor.
Record that microphone to the recorder at a strong volume.

Doing that will give you the quietest recording your gear can give you.


(If you have crappy microphone pre amps, they will act the same way as a noisy mic.)
 
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if you normalize a noise floor it will be raised together with the signal. So what you want is a full signal with low noise. I guess there is something wrong in your signal chain.
You always want the hottest possible signal! You have to be careful with peaks so good preparation and testing is mandatory....
 
I think you may be confusing background noise with "noise floor". Noise floor is the noise that the system creates and that is always there (the noise that the equipment on it's own creates).

I would always go with a proper signal level. Even if you have a lot of BG noise. It's easier to work with a hot signal than a low one. If you don't record it it doesn't exist. If you record more than you want there is a chance you can get rid of some of what you don't want.

And Normalizing isn't a good thing to do as a rule. But again I think you are confusing terms. Normalizing has a specific meaning and you can't do it on the fly when recording. I think you are referring to volume changes. ie "Is it better to record soft and turn it up or record hot in the first place".
 
Or to put it another way:

You want the strongest signal possible as early as possible in the signal chain. As self-noise (or noise floor) is more or less constant, signal-to-noise ratio can be increased by maximizing the signal at the earliest stage. Each device that increases the signal level increases the noise from all previous devices proportionally (consider each operation in your DAW/NLE to be a device). That is, signal-to-noise ratio will NEVER get better, and will in practice ALWAYS get worse with every bit of processing you do. Thus, an optimal signal up front and no further processing has the least noise. So, to answer your question:

1) Choose the mic/place the mic/coach the actor in such a way that the voice level is not "too low". This will help with both noise floor AND background noise.
2) Set the recording level to the closest you can safely get to the final level you want.

(Yes, I know about EQ and "noise reduction". These are creative signal modifiers, not the same as reducing noise in your signal chain. And they are a last resort, not a good plan!)
 
One thing my college sound engineering prof said:

"If you take away one thing from college, it's this. Your first gain stage is the most important. Don't F**K it up".
 
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