How Long to Record Room Tone?
 

I am recording interviews and in some cases will only use a lav. But I can use a boom mic later on to record room tone. If the interview lasts 30mins, how long should I subsequently record room tone for? Can I just loop it?

Any general tips on room tone recording an mixing it in during post production?

Thanks much as always.

Hello Peter,

Room tone is not just the sound in a room. It's also the sound of the mic, the preamp, and all circuits that contribute to the sound. You can't get proper tone by recording in a room with a different mic than you used to record.

A room doesn't necessarily have just one tone. Each setup in a room may have different tone based on the acoustics of the room and the noise sources, e.g. placement of HVAC ducts, lighting buzz, outside noise getting in through a window, coming in through a doorway.

Plug in a mic, walk around with it and listen to the sound field change. You'll hear what I mean.

How much? Usually 30 seconds is plenty.

See you at NAB.

Regards,

Ty Ford