Definition
Slotting is the technique of giving each element of the mix its own “slot”: a frequency zone, a moment in time and a position in space in which it is the protagonist. It is the active answer to masking: instead of fixing things case by case, you design the fit. You work on three axes: frequency, time, space.
1. Slotting in frequency (complementary EQ)
For each pair in conflict you choose who owns a frequency: there, one has a boost (or nothing), the other a cut.
- Kick and bass: two strategies.
- Kick below: the kick owns 45–60 Hz, the bass 80–120 Hz. Cut 3–4 dB at 50 Hz on the bass, 2–3 dB at 100 Hz on the kick.
- Bass below (typical of trap and 808): the 808 owns 40–60 Hz, the kick the punch at 80–120 Hz and the click at 2–5 kHz; sidechain or non-overlapping notes.
- Snare and vocal: snare with body at 180–250 Hz and crack at 4–6 kHz; vocal with presence at 2–3 kHz and a cut at 4–5 kHz only if needed.
- Double-tracked guitars: one with more 1.5 kHz and less 3 kHz, the other vice versa (and opposite pan).
- Pad and lead: dark pad (LP 3–5 kHz, cut at 1–2 kHz), bright lead in that zone.
Rule: narrow cuts to correct, small wide bells to “shape”; a move of ±2–3 dB is often enough.
2. Slotting in time
Two elements in the same band can coexist if they do not play at the same instant.
- Sidechain: the bass ducks 3–8 dB when the kick plays (fast attack, tempo-based release: 50–150 ms).
- Rhythmic arrangement: the bass avoids notes on the kicks (house: bass on the offbeat between the kicks).
- Envelopes: short kick, bass with a slightly softer attack.
- Ducking of reverbs from the vocal: the tails swell in the pauses.
- Call and response: the riff answers the vocal in the pauses.
3. Slotting in space
- Panning: guitars L/R, piano slightly left, hi-hat slightly right, vocal, kick, bass, snare in the center.
- Depth: some elements in front (dry, present), others behind (reverb, fewer highs) (see “Depth and perspective”).
- Width: wide pads, main elements narrower.
Sample slotting map (electropop)
| Element | Main frequency | Timing | Space |
|---|---|---|---|
| Kick | 50–60 Hz + 3 kHz | on the quarter notes | center, front |
| Bass/sub | 70–110 Hz | sidechain from the kick | center, mono |
| Snare/clap | 200 Hz + 5 kHz | 2 and 4 | center |
| Vocal | 200 Hz–4 kHz, presence 2.5 kHz | protagonist | center, front |
| Piano | 300 Hz–2 kHz, carved at 2.5 kHz | chords | slightly left |
| Pad | 400 Hz–3 kHz dark | long | wide, back |
| Lead | 1–5 kHz | between vocal phrases | center-wide with delay |
| Hi-hat | 8–12 kHz | sixteenth notes | slightly right |
Example in A minor
Track at 122 BPM: Am bass on the offbeat (A1 on steps 3, 7, 11, 15) with sidechain from the kick (release 90 ms); kick tuned around 50 Hz with a cut at 110 Hz; bass with a cut at 50 Hz. Piano Am7 – Dm9 on the left with −2 dB at 2.5 kHz; vocal with +2 dB at 2.5 kHz. Wide, dark Fmaj9 pad. Every element has a place, and the mix gets louder without raising the faders.
Common mistakes
- “By-the-table” slotting without listening: the numbers are starting points.
- Carving too much: in solo the instruments sound strange, but what matters is the mix; still, beyond −6 dB on a wide band the element loses its identity.
- Forgetting time: the solution is often in the arrangement.
Exercise
Draw your own slotting map (like the table) before mixing your next track. After the mix, compare: where did you change your mind and why?
Related topics
“Frequency masking”, “Depth and perspective in the mix”, “Compression” (sidechain), “Drum design: the synthesized kick”, “Designing 808s and basses”.