Beyond The Clap Test - Part 1: What Do We Need To Know, And Why

You’ve probably done the Clap Test before—gone into a room
and clapped your hands in individual, staccato hits to quickly evaluate the sound of a room. I’ve done it myself many times. It gives us a quick idea of the reverb time in the room: useful, but incomplete... and it’s difficult to discern the overall sound of a
room with any one test.

As a result, one of the most common questions I get in my acoustics work is, “How do I tell if my room sounds good?” This innocent question is deeper than it seems, and the answers are not always obvious. One response is Duke Ellington’s classic maxim, “If it sounds good, it is good.” But this speaks more to the subjective, emotional experience of music in the room, and not so much about the acoustic qualities of the room itself.

As sound recordists, mix engineers, and producers, we should familiarize ourselves with evaluating the sound of the rooms we work in, because the room always affects the sound of everything we do. This holds true for one-off tracking sessions in unfamiliar rooms, as well as for rooms we are setting up for regular use as personal or project studios.

The room’s sound will always be present to some degree in any recording, even when close-miked (though the room’s sound is minimized with close miking), so it needs to be well understood. When tracking’s done, setting up an accurate listening environment for mixing is essential to any studio. One of the best lessons when I was learning how to mix was that if mixes didn’t come out well, it wasn’t so much an indictment of my skills (though I do hope to continue to improve those for the rest of my life), but rather of the fact that I just couldn’t hear accurately.

A solid understanding of room acoustics and familiarity with evaluating a room’s sound are essential skills to master in the quest for better audio. Let’s take a look at some basic characteristics of room acoustics, so we can use these concepts to evaluate a given room’s sound quality.