So, you're planning to shoot some scenes that take place in a bathroom, warehouse, or some other type of reverberant space? Well, that's pretty awesome, but wait until you realize that you'll have to eventually record sound in a room full of echoes, which is especially challenging when dialogue is involved.
While ADR and post-production software can help avoid or (kind of) fix this issue, you might want to know a few tips on how to eliminate echoes so you can record sound on set without them bouncing all over the place and ruining your recording. In this video, Michael Lohrum of DIYCameraGuy explains how to "treat" reverberant rooms so you can do just that.
Every surface will reflect sound waves to some degree, but those that are hard and smooth, like a tile floor or bare walls, do it best. This is why it's important to put up obstacles that absorb sound waves and cut down on echoing. In the same way that every surface reflects sound waves, they also absorb them, but it's your job to figure out which ones will absorb them enough to eliminate echoes.
Of course, sound blankets were made for these types of situations, but if you don't have any on-hand, Lohrun suggests finding materials that are heavy enough to absorb sound waves and porous enough that sound waves can pass through it, bounce off of other surfaces, and pass through again. This means clothes, normal, everyday blankets, towels—really anything of that nature.
Then, when it comes time to record audio, just throw the material on the reverberant surfaces, like wood/tile/etc. floors, walls, bathtubs. You can even throw a blanket on a boom and hang it close to your subject to try and cut down on any reverb.
What are some other clever ways to soundproof an echoey room? Let us know down in the comments.