Sound quality falls fast with distance. A mic 30 cm from the mouth beats an expensive mic at 2 metres.

Use it when. Every line of dialogue. If the mic cannot be close, the shot is a wide and you will loop the line later.

On the phone. The phone’s own mic is 1.5 metres away on a tripod. Never use it for dialogue.

A small mic clipped at the chest, about a hand’s width below the chin, pointing up.

Use it when. Most of your dialogue. It follows the actor, so it works for moving shots.

On the phone. A wireless lav that plugs into the phone is the cheapest big upgrade. Hide it under a collar with a small loop of cable to stop rustle.

A mic on a pole held above the frame line, pointed down at the mouth from in front.

Use it when. Two people close together, or when clothing rustle ruins the lav. Sounds more natural than a lav.

On the phone. A second phone with the wireless receiver on a broom handle works. Watch the top of the frame in every shot.

Thirty seconds of the room with nobody speaking, recorded with the same mic in the same spot.

Use it when. Every location, every setup. The editor pastes it under cuts so the silence between lines does not jump.

On the phone. Record it before you strike the set. Say “room tone” out loud at the start so the file is easy to find.

Fans, air conditioners, fridges and traffic sit under dialogue and cannot be removed cleanly.

Use it when. Before every take: switch off the fan and the AC, close the window, unplug the fridge. Turn them back on between takes.

On the phone. A room is quiet at midnight and noisy at 3 pm. Schedule dialogue for the quiet hours.

When sound records on a second device, one sharp clap at the start of each take lines them up in the edit.

Use it when. Every take with a separate recorder. Say the scene and shot number, then clap in frame.

On the phone. If the mic plugs straight into the phone, you get sync for free. Still slate: it labels the take.