As a location sound recordist, it’s extremely helpful to know what kind of space you will be recording in before the production starts. Sometimes you’re included in that decision process and sometimes you’re not. Many times, you will show up on-location and you’ll have to figure it out then. When you walk into a room you have to determine how reverberant it is. People sometimes call it echo but it’s actually reverb, which is sound reflecting off the walls, floors and ceilings. Flat surfaces like tile and wood floors and high vaulted ceilings cause the sound to bounce around the space. If you clap your hands, you can hear the sound bounce around and trail off. Unfortunately, there’s really no way to remove the reverb after you record so you want to reduce it as much as possible on-location before filming begins.
In come the sound blankets! To help absorb the sound reflections and reduce the reverb in the room, hang up sound blankets around the set and put them on the floor around your actors. You can also use packing or moving blankets, which vary in thickness. The thicker the better. You probably won’t be able to remove all the reverb in the space but it will definitely help control it and make it less noticeable. If it’s a nice hard wood floor, it’s good to put down a blanket anyway to protect the surface from scratches as you set up the gear. Use a c-stand with a grip head and arm to hang sound blankets just off camera to create sound absorption around your actors.
Of course, every situation is different and you’ll have to adjust as needed especially if the camera is changing positions, you don’t want to see the blankets on-camera. It’s always good to put a lav mic on the talent AND use a boom mic to capture the actor’s dialog and then choose the best sounding options in post. Remember to get the boom mic as close to the actor’s mouth without being seen on-camera to help with reducing the reverb the mic picks up. The further the boom mic is away from the talent, the more room sound you will hear. It’s always good to have at least 4 or 5 sound blankets available on every shoot to control the sound and to protect flooring and furniture. Happy recording!