The answer is ” to eliminate sound delay “.
In an earlier post, I explained why DJs wear headphones on one ear. While mixing, you need to hear both the main sound (currently playing song ) and the upcoming one in real-time.
Why real-time ? Let me explain.
Beatmatching is what makes a DJ. In order to beatmatch the proper way, there has to be no delays in audio whether it’s coming from speakers or your headphones.
The whole purpose is to align the beats together on both tracks with the same tempo and make a perfect transition.
How can you do that without hearing the music in real-time ? You can’t.
Next time you go to a club, pay close attention to the DJ booth. You’ll see at least one, most probably two speakers in there, facing the DJ either from sides or the front.
In a dance hall, speakers are mounted all around the room and the DJ booth is naturally not in the middle of it.
Reason For Monitor Use
While DJ’ing, what you hear from those speakers is always delayed and echoed. You can never rely on the main sound system for mixing.
You need separate speakers closer to your ear to avoid any possible delay and echo in sound.
Now, back to the beginning. The reason we wear headphones on one ear is that the other one can hear what’s currently playing from those monitor speakers.
You hear main sound from the monitor, next song in your headphone and beatmatch.
There are smaller sized DJ and studio monitor speakers which you can use for your home setup.
My advice is, try to buy active (powered) speakers. They are self amplified and don’t require additional power supply. Just plug and go.