Hardware & signal path
Isolator
An isolator is a three-band EQ that removes a band completely rather than attenuating it. Where a standard mixer EQ bottoms out around −26 dB, an isolator goes to silence, which makes a bass swap absolute rather than gradual.
In practice
A true kill makes the bass swap one decisive move; a −26 dB cut lets you blend the handover instead.
Many club mixers have a switch that changes the EQ between the two behaviours — find it before the set rather than wondering why the low end will not clear. With the isolator engaged, swap the bass on the downbeat and commit: half a kill sounds like a mistake in a way a half-cut does not. The boost side is where the danger lives, because an isolator’s boost range is generous and the low band is the fastest way to run out of headroom on the master.
Silence
Where an isolator bottoms out
−26 dB
Where a typical EQ stops
On the downbeat
When to commit the swap
Where these come from: Club-mixer EQ specifications and the technique they imply, not catalog figures — nothing we store describes a mixer. For what we can measure, see the move it is used for.
Why it matters
The difference is audible in exactly one place: the bottom of the knob. A −26 dB cut leaves a trace of the outgoing bassline under the incoming one, which is usually fine and occasionally the thing making a blend sound crowded.
It also changes how the move is timed. With a true kill, the swap is a single decisive gesture on the beat; with a conventional EQ, it is a crossover that can be spread across a few bars and blended by ear.
Frequently asked
What is the difference between an isolator and an EQ?+
How far down they go. An EQ attenuates a band — typically to about −26 dB — while an isolator removes it entirely, which is why the bass swap on one is instant and on the other is a crossover.
Is a kill switch the same as an isolator?+
Effectively yes at the bottom of the travel. A kill removes the band; an isolator is a full three-band EQ whose bottom position is a kill, so it gives you everything in between as well.
Should you boost with an isolator?+
Sparingly. The boost range is wide and the low band eats headroom faster than anything else on the mixer, so cutting the other bands usually achieves the same balance without touching the master.
Related terms
Kill EQ
A kill EQ removes a band completely when the knob is turned fully down, rather than merely attenuating it. On a mixer with true kills, taking the bass to zero leaves genuinely nothing below the crossover.
Three-band EQ
A three-band EQ splits each channel into low, mid and high and gives you a knob for each. It is the primary tool for deciding which parts of two records are audible at any moment.
Rotary mixer
A rotary mixer replaces channel faders with knobs. It usually has no crossfader, an isolator-style EQ and a deliberately unhurried response — the design assumes long blends rather than cuts, and the format encourages them.
Filter
A filter removes everything above or below a moving cutoff point. A high-pass strips the bottom away as you turn it up; a low-pass takes the top off as you turn it down.
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