EQ Mixing for DJs: Transitions with Lows, Mids and Highs

EQ mixing is one of the core techniques in DJing: with the 3-band EQ on a mixer or controller, two tracks can be blended so that their frequencies do not get in each other's way. This article sums up what lives in the three bands, how the classic bass swap works and how EQ mode differs from isolator mode.

What is in the lows, mids and highs?

Most DJ mixers and controllers split each channel into three bands. Roughly, the ranges can be described like this: lows around 20 to 250 Hz, mids around 250 Hz to 4 kHz, highs above 4 kHz.

• Low: sub-bass, the weight of the bassline and the body of the kick drum.
• Mid: vocals, melodies, the body of the snare and the presence of synths.
• High: hi-hats, cymbals, percussion attack and the brightness of a track.

It helps to keep the roles apart: the gain control sets the source level, while the EQ shapes the blend of two tracks. A properly set gain structure helps prevent clipping when working with the bass EQ.

The bass swap as a core technique

The best-known EQ technique is the bass swap: on the channel of the playing track the bass is turned down, on the channel of the incoming track it is turned up. The reason is that two basslines playing at full strength at the same time quickly sound boomy because the low frequencies overlap. The aim is to have only one dominant bassline fully audible at any given moment.

Timing is crucial. The swap is placed on the first beat of a clear musical phrase, often after 8, 16 or 32 beats. Any major change outside the natural phrase length is noticeable and makes the transition sound awkward. Planning transitions while preparing a set makes this easier – more on that in preparing the perfect mix.

Cut rather than boost

When two tracks clash in a frequency range, it is usually safer to cut that band on the competing track than to boost it on the other – this preserves more headroom. When cutting, either a gradual movement or an instant, complete kill works best; an abrupt cut to a halfway position tends to sound strange in any band. The technique has its limits with vocals: two lead vocals at once cannot be layered cleanly, even with the EQ.

EQ mode or isolator?

Some mixers offer an isolator mode alongside the classic EQ. A normal EQ often leaves part of the band audible at its minimum setting, while an isolator removes it far more deeply. On Pioneer DJM mixers, EQ mode reduces a band by a maximum of around 26 dB with the knob fully turned down, whereas isolator mode goes all the way to complete elimination. From roughly the middle of the knob's travel, the isolator cuts harder than the EQ. That makes the isolator particularly suited to full-band swaps, and EQ mode to gradual, flowing blends. An overview of the different device types is given in DJ controller vs. CDJs.

Frequently asked questions

Why shouldn't two basslines play at once?

Two full basslines overlap in the low frequency range, so the mix quickly sounds boomy. That is why only one dominant bassline should play at full volume at any time.

When is the right moment for a bass swap?

On the first beat of a new musical phrase, often after 8, 16 or 32 beats. Changes outside the phrase length are noticeable to the audience.

What is the difference between gain and EQ?

The gain control sets the basic level of the source, while the EQ shapes the sound of individual frequency bands and therefore the blend of two tracks.

Source: Digital DJ Pool, Home DJ Studio, WaveAlign