Las Vegas has a soundtrack all its own, one that’s syncopated with the soft hum of neon lights, the dings and clangs of casino games, and the melodies that pour out of Las Vegas concerts in small clubs and huge venues. Whether you’re catching a show at the House of Blues Las Vegas or shimmying across the dance floor at Marquee, every infectious beat you hear owes its sound to a crucial piece of audio equipment: the equalizer.

Why are equalizers necessary?

For humans, low-frequency sounds are the hardest to hear. These sounds include the bass-heavy thumps that typify dance and house music and ghosts’ late-night square dancing. Because they’re harder to hear, though, these frequencies often need to be played at a louder volume, and equalizing them is necessary to avoid distortion caused by turning their volume up so high.

How does it work?

Every song is a combination of sounds, each with its own high, middle, or low frequency. Equalizers turn these frequencies up ("boost") or down ("cut"), depending on how a DJ or sound technician wants the track to hit our eardrums. The equalizer's job is to divide these frequencies into different bands, which the DJ then controls through dials. Better equipment means more bands and more manual control to boost or cut the various frequencies in a song to suit the venue or the tracks being mixed.

Where do you need it?

Not all music venues are created equal. Some are short and shallow; others are cavernous, prone to echoes and deep, full sounds. Even less predictable are the shapes of cars, bedrooms, outdoor barbecues, and other spaces where people blast tunes—a disparity that can make any given song sound completely different depending on where it’s played. Enter the equalizer, which helps even out the sound to compensate for these differences. Plenty of audio equipment, including car radios, phones, and CD players, already have built-in equalizers, and DJs regularly use professional-grade equalizers when playing music in unfamiliar venues or trying to seamlessly mix together two discordant songs.