Filling the blanks with "room noise"

[Marcus Frakes]

During edits (sony Vegas, Avid, etc) there are the occasional shots where you have no audio. For this, I usually ran an additional track of ambient room noise that I prerecord during the setup phase of any scene. However I found the total noise almost doubled in instances when it plays with a dialog track.

 

Of course the dialog has the same ambient background and the 2X output kind of makes sense (1 + 1 = 2). But it's the SAME room and shouldn't do that right? Like if you take a music track, copy and paste it into another track, you don't increase the volume. You can get a delay, by moving one track slightly, but not a gain.

 

Is there a better way to approach this? How do pros add room noise back into a scene and does it overlap the dialog?

 

Ciao..

[Gordon Highland]

I often let it overlap the dialogue because it masks some of my edit points where the background level changed or I added gain to certain shots. You don't have to use the ambient track at the same volume; even a little will do, and you don't have to layer it over the other track if you don't want; you can just splice or crossfade it in to fill the silent holes. Most of the time my ambience gets augmented with some effects or ambiences from my CD library that are more interesting and realistic than what I recorded.

 

Also, when the room tone track was recorded alone, it's possible it may have been boosted with a compressor or some type of gain makeup, or mic placement.

Edited November 16, 2005 by Gordon Highland

[Guest Charlie Seper]

Montage,

 

I don't know what you're using to do your editing but try looking through the help files for info on using "volume envelopes".

 

I don't know if dubbling the ambient noise will "double" the volume (I suspect not) but it will certianly raise it.

[Michael Collier]

sound works in addative fassion (think of how light works) yes, if you add room noise underneath a track containing room noise and dialoge, it may not increase volume much, but more importantly the white noise to dialoge ratio would double, effectivley making the background sound twice as loud. What I normally do is only put ambient sounds in where I have absolutley no sound. if there is a gap in the audio I will do a butt cut to replace the natural room drone. if the changover is too stark then I would try a linear cross fade, if that still doesnt correct it, try a natural fade (have 80% of the volume decrease in the first second or so of the fade, then slowly pull the last 20 out over the next 3, do the oposite when brining up the ambient sound) That way you keep the dialoge to white noise ratio at a constant level.

 

The ambient sound should never overlap dialouge.

 

if the noise is really bad in the dialoge track, try and eq it out. most rooms have similar white noises, which are in a different frequency range than most voices. Try a 60hz "notch" filter. it should take any sound in the 60hz realm and attenuate it at least 5db. most north american homes have 60hz power, and that induces sound in the mic and in the line just by the magnetic feild created. past that find the range that the white noise is in and attenuate that out too. The range is usually determined by the acoustic properties of the walls and carpet and surrounding noise generators (washing machines, etc)

 

If you have a spectrum analizer software play the ambient track and note what frequency ranges the ambient noise falls into. Then use the EQ to attenuate those ranges. be carefull not to harm the final track too much, and add the same audio filters to the ambient gap filler so that is a constant.