Bass is like a warm blanket. It's a seductive sensation that we humans love nearly across the board.

Hell, bass is the reason Beats by Dre ever took off in the first place, and what's happened since it did is proof that we love bass.

The weird thing about bass is, in practice, it has little in common with the other sounds that make up music and sounds we can hear. High frequencies (i.e. not bass) are directional, so people tend to put tweeters up at ear level.

Conversely, bass is omnidirectional. Below about 80 Hertz (one Hertz is one wave per second) where you hear the boom of a kick drum, the sound travels out in all directions.

That's why bass gets louder when you place your speakers or subwoofer in the corner. What's actually happening is the corner is reducing that sphere of bass down to one-eighth its size and projecting it out in a more focused beam.

Put some music on, and walk around behind your speakers. If you can't do that, pick them up and position your head behind them. Unless they have an omnidirectional tweeter or one mounted on the back, chances are you will just hear the low stuff. If your speakers are properly made, you'll hear plenty of bass and hear it soften in volume at about the male vocal range and up.


So bass is a different creature. Its waves are much larger than the rest of the spectrum. An 80Hz wave is 14.2 feet long, and a lot of the bass in modern music and movies is lower than that. At 20Hz, which is the bottom limit of human hearing and which is a standard benchmark of performance for a good subwoofer, the wave is nearly 50 feet long.

Compare that to a ride cymbal tap, which comes in around 10KHz (10,000 Hertz or 10,000 waves per second) and whose wave measures something like 1.3 inches in length. The small waves fly directly at you, and if you're out of the listening zone, you may not even hear them.

So listening environments are dealt with differently for different parts of the sound. For the high, small-wave stuff, you just make sure the tweeters are close to pointing at your ears in the prime listening spot.

For the low stuff, all kinds of tricks are used to even things out. Because of the huge waves relative to a small listening room, bass tends to bounce around a lot and interfere with itself both constructively and destructively. That means when wave crest and bouncing wave crest meet (or wave troughs), they double up the volume. When trough meets crest, though, the waves cancel out and the volume drops to nothing.

In a typical listening space, the effect can go back and forth, doubling up and canceling out as the pitch of the bass rises. This is called "comb filtering" and results in peaky, inaccurate bass. Corners tend to do this because bass energy builds up in the outer boundaries of rooms.

Sometimes the best spot for the sub isn't the corner. More next week.

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