Delayed audio

Paul McGowan writes:

Here’s an interesting fact. If we play our stereo system outdoors we’d have no room problems, yet not much would sound right.

Rooms are somewhat of a double-edged sword. On the one hand, their hard boundaries enable our speakers to fill the room with sound. (Imagine your stereo system trying to fill Yankee Stadium). On the other hand, those very walls get in the way of good audio.

The most difficult of problems in rooms are the floors and ceilings (though if you’re blessed with a tall ceiling, you need only stress about the floor). A good carpet can work miracles in most rooms.

The next set of problems are typically counted in the fours. We call them walls. Sound pressure waves from our speakers travel straight to our ears, and soon after, we get another blast—slightly out of time from the first. The amount of delay is dependent on the closest side wall. The delayed audio is known as a first reflection.

If you visited our room at RMAF you would have noticed two diffusers, one on each side wall (you can watch the video here). These wooden contraptions were strategically placed right at the point where the speaker’s sound waves first hit the wall. The diffuser scatters sound and makes it harder for the ear to pinpoint its location and that’s a good thing.

If you’ve not addressed the first reflection of your room, you might want to WATCH THIS VIDEO I prepared for you. In it, I discuss how reflections happen and then offer a clever technique to pinpoint the exact location along the side wall.