Just about any picture or video you look at of a DJ performing will show that they’re wearing large over-ear headphones specifically. It might seem counterintuitive – wouldn’t they need to hear themselves playing just as the nearby audience would?
The answer is yes they obviously do, but there are a number of not so obvious factors that complicate a DJ simply listening to themselves naturally in order to fully do their job.
Performers on stage need hearing protection (and so do attendees!)
Clubs and other such music/dance venues are typically very loud. How loud? Well, there are a lot of quoted figures, and this will obviously depend on where you actually are at a venue, but a rough range we can reasonably surmise is anywhere from 100 dB to a whopping 130+ dB.
This range is well above safe levels to avoid hearing damage, which, according to the CDC, are as follows:
Noise above 70 dB over a prolonged period of time may start to damage your hearing. Loud noise above 120 dB can cause immediate harm to your ears. (source)
It’s easy to see that any DJ who is regularly up on stage, and often near the various loudspeakers that are feeding the room, is all but guaranteed to damage their hearing, and probably to a very severe degree, if they never use hearing protection.
Relevant PSA: patrons of music venues should invest in hearing protection as well!
“Cueing” the next song
If you go to a club, you’ll notice that the music never really stops and songs seamlessly transition to one another, often with the beat preserved so that patrons can easily keep dancing along – any experienced DJ will tell you that clunky transitions between songs can quickly kill the precious night life vibe.
This is accomplished with a very deliberate effort from a DJ using specialized equipment, and it’s arguably the most important part of a live DJ’s job. Part of this process is something called cueing, which basically means to pick and pull up the next song, match its beat, tempo, pitch, and whatever else necessary to the currently playing song, then phase it in when it’s ready to go.
This is why a good pair of headphones is a crucial piece of equipment for DJs – it’s how they listen to the cued song and get it ready to go without the audience hearing the tinkering, only the smooth transition.
Why do DJs sometimes take their headphones off or put one to the side?
This is mainly the simplest/fastest/easiest way to hear both the current song as the audience is, actually playing over the sound system, as well as the song currently being cued. Over-ear headphones specifically are easiest to constantly take on/off, as opposed to in-ear monitors, which while they can work fine, are often too much of a chore to properly insert to be practical for DJing.
But putting/taking headphones on/off isn’t always a totally reliable method.
Monitoring in the DJ booth, or wherever they may be, might not be good. That is to say, the sound they hear coming out of the main system is not reliable enough to work off of. Venue speakers are optimized for listening in a centralized dance area or such, as you can probably imagine, and the quality of sound can be significantly impacted if you’re tucked away in a corner booth. This is on top of the fact that critical listening to loud club music can already be innately challenging.
Sometimes a DJ booth will have a nice set of monitor speakers, or be well built/organized to hear the main loudspeakers, or sometimes you have no such amenities and have to just kind of wing it.
Picking a good pair of specific headphones for the venue, and knowing when and how to use them, either fully on, partially on, or completely off, is indeed part of the skillset of a good DJ. Sometimes you need to really hear what’s going on with the song(s) with a pair of monitoring headphones, and sometimes you need to feel connected with the actual sound to get a sense of what’s going on out in the crowd.
