If you’re interested in learning to DJ, or just curious about what a DJ actually does with all those buttons, knobs and faders behind the decks, then please read on. This article explains the fundamental skills behind DJing and the purpose of each piece of hardware in a DJ’s standard setup. Come the end, you should know enough to give it a go yourself.
Let’s quickly clarify exactly what a DJ does and doesn’t do.
A DJ plays records in sequence, by cueing them up in turn and mixing them in and out. A surprisingly common misconception is that DJ’s create the music they play whilst on the go – in reality that happens at great length in a studio somewhere with a raft of instruments, synthesisers, samples and other technical equipment. Some DJ’s do play ‘live’ – much like a rock band does – but this requires a totally different setup, and is fundamentally different to DJing.
A DJ’s key skills
The process of mixing one record to the next can be broken down into four steps:
- Choose the next record – sequencing
- Beatmatching, if necessary
- Count bars and pressing play
A record’s speed is measured in beats-per-minute, and virtually every record has a consistent speed throughout. Most genres have a customary BPM – for example most deep house is around 120bpm, techno faster at 130bpm, and drum ‘n’ bass right up in the 170bpm range.
DJ’s speed up and slow down records using the pitch controls on their decks, so that their respective BPM’s match – that’s what we mean by ‘beatmatching’. So why do it? When two beatmatched tracks are played simultaneously, all the kicks, hats, snares and bars strike in unison, which maintains the rhythm. If they’re even slightly out of sync, the mix will descend into an awful mess and all rhythm goes out the window.
Beatmatching isn’t always necessary, as sometimes it’s impossible to find common ground between two records. The answer would be a swift crossfade, or switch in volume. As a general rule, mix fast when transitioning between two records with significantly different BPM’s.
The first job of a DJ is to play good music – highly subjective of course, but you get the idea. Track selection is about context – choosing the right track for the right time.
Tastes aside, there are elements of track selection that are all scientific. Mixing a new track in with a key that harmonically compliments the incumbent will sound good, whilst heavy pitching can make it impossible mix in a track with a significantly different BPM – this happens a lot when mixing between genres.
There’s a lot to consider when sequencing tracks.
Having foundation knowledge of the structure of music is important to DJing – fortunately it’s quite easy. Most house music has a 4/4, and ‘four-to-the-floor’ beat – that means a kick on every beat. Have a listen to the video below… one two three four, one two three four…
A ‘bar’ in music is a segment of time defined by a given number of beats. If we’re looking at a 4/4 house track, think of bars of eight, sixteen and thirty-two notes. Why’s this relevant? Pick a house track like below, and count notes to thirty two – what happened? Music is generally written in a way that introduces new layers of sound at the start of a new bar, simply because it sounds nice – DJing is no different.
Once you’ve chosen and beatmatched your next record, turn to the incumbent and listen for the start of a 32-beat bar, hitting play as the next bar begins. By doing this, both inbound and outbound records will add and remove layers of sound simultaneously, which sounds nice and musical.
The vast majority of dance music is written in 4/4, so the rule of 32 is very reliable when DJing. It gets tougher when the likes of Radiohead start writing to in 10/4 – let’s not go there.
Play a record start to finish through your laptop or phone’s in-built speakers – have you heard the whole record?
No, actually you have only heard about half of the record.
Why? Your laptop speakers can only reproduce half of the record’s frequency range, and you wont hear any sound below about 200hz. This means you’ve lost all the ‘boom’ of the kicks, and taken the bass out of the bassline. In dance music especially, these are two primary rhythmic elements you can’t do without.
There are two scientific concepts essential to understanding how to EQ:
Your ears struggle to distinguish between same-frequency sounds
Have you ever noticed you can’t hear the bass in your headphones so well when you’re on a train, bus or plane? This is because the engine is rumbling at a low frequency – the same low frequency of your kick or bassline. To summarise without getting scientific, your ears can’t distinguish between two noises in the same frequency range, and it all sounds muddy – losing the very clarity that defines one record from the next.
Two same-frequency sounds played together increases the overall volume
Something else happens when you play two sounds in the same frequency range over one another, it gets louder. The thing is, soundsystems can only go so loud before they hit their maximum amplitude ceiling – after that the signal clips and distorts, which sounds bad.
When you’re on that bus or plane, your only option is to turn the sound up – you can’t turn the engine down can you? Fortunately, DJ’s don’t have this problem because their mixers can turn frequencies up and down.
Equalising is the practice of balancing the frequencies between the two, or more, records in a mix so that they are clear and undistorted. If you want to learn more about EQing, I’ve written a far more comprehensive guide here.
Understanding the hardware
So we now know what a DJ does back there, but how do they do it? A DJ’s controls look like a spaceship’s to an unknowing eye, but getting to know them isn’t so daunting. The trick is in understanding the journey and changes sounds (records) make from their source right through to the speakers.
Inputs – the source of sound
Plug in your iPod to your speakers, and it sends the music through to the speakers, which then reproduce it out as audible sound. A CDJ, or vinyl deck does the exact-same thing – it’s the source of the music. By inserting your CD or 12” and pressing play, the device will send a sound signal through the phono cables and into the speaker. CD and vinyl decks are different in that they’re fitted with pitch controls to slow up and speed down records – to beatmatch them.
What an iPod can’t do is play two records at the same time – you’re going to need two iPods. Again this concept is the same with CD and vinyl decks – you’ll need multiple decks to play multiple records at the same time.
You may wonder where laptop/digital DJing and MP3s come into all this. Think of the laptop as another MP3 player – another input feeding into the mixer. There’s no need for multiple laptops however, as with the right soundcard, DJ software like Serato or Traktor Scratch can send multiple inputs (records) into the mixer.
The mixer consolidates all the inputs, and controls the volume and frequency levels of each input – it’s where all the equalising takes place. The mixer doesn’t make the sounds, it affects them. Sound passes through the mixer, in one end and out the other – we call this an ‘envelope’, in musical terms.
Mixers are fitted with a minimum of two channels, but most club mixers (like below) have four or six. Each channel comes with its own volume fader and frequency controls – usually split by low, middle and high frequencies. DJ’s pass sound (music) through these channels and use the controls to blend (mix) two records together.
All the inputs’ signals are sent through the mixer’s channels and consolidated into a single master output, which is sent to the speakers and the crowd. This is the end product of all the beatmatching, equalising, bar counting and track selection that’s gone into the mix.
The end product is precious, so the DJ works in private within their headphones. Mixers allow DJ’s to listen to, beatmatch and EQ the different channels through their headphones, without interfering with the master output. We call this process cueing - preparing the next track.
If you want to give it a go, you’ll need a mixer, pair of speakers, headphones, and either two vinyl/CD decks or a laptop with some DJ software on – and loads of music of course. CDJs are really pricey when compared to turntables, but then again, MP3s are really cheap when compared to vinyl. The cheapest way to get into DJing it to buy a MIDI controller that doubles up as a mixer, and download some DJ software like Virtual DJ or Serato. You wont be doing much beatmatching as the software does that for you, but you’ll learn the skills that really matter – equalising and sequencing. Ebay is full of second-hand hardware, so take a look, and remember you can always sell it on again if you want to upgrade.
There is an argument that digital DJing isn’t real DJing, and that it’s too easy without the beatmatching. If you’re asking my opinion, I say all that matters is a quality end product!
There’s a lot to consider when mixing one record to the next, but once you’ve got the hang of it, it’s a doddle. I hope this has been helpful, and if anything’s unclear then just ask me in the comments. DJing is an expensive habit, but it’s a lot of fun and very rewarding – if you’re intrigued, just go for it.