What the mix bus is
The mix bus is the point where all tracks and buses are summed before the output (in FL Studio, the Master track or a dedicated “Mix” track that feeds the Master). A light chain on the mix bus gives the mix cohesion and character and lets you hear part of the final result while you work. It should be distinguished from the mastering chain, which is applied to the finished, printed mix.
Mixing “into” the chain
Many engineers insert the mix bus chain early (after the first balance) and mix while listening through it. This way, decisions on levels and tones take the group compression and saturation into account. If the chain is added at the end, it changes the balances decided without it (the vocal drops, the bass pumps). Rule: insert it within the first quarter of the mix and then do not change it much.
Typical chain
- Broad corrective EQ (optional): slight tilt, HP at 20–25 Hz. Often not needed.
- Glue compressor (SSL bus style): ratio 2:1 (or 4:1 in denser genres), attack 10–30 ms, auto release or 100–300 ms, 1–3 dB of reduction on the loud passages. HP in the sidechain at 60–120 Hz to prevent the kick and 808 from making everything pump.
- Saturation (tape, console, transformer): 1–2 dB of drive, density and harmonics.
- Color EQ: shelf +0.5/+1.5 dB at 10–12 kHz (air), possibly “Pultec” lows at 30–60 Hz.
- Control clipper or limiter (for listening only, or for the premix): 1–3 dB of reduction to get closer to the final loudness while working. It must be turned off in the export for mastering, unless you do the mastering yourself and decide to print this part.
Reference values
| Genre | Glue compression | Notes |
|---|---|---|
| Pop, R&B | 2:1, 1–2 dB | Auto release, attack 30 ms |
| Hip hop, trap | 2:1–4:1, 1–3 dB | Sidechain HP 100 Hz so the 808 does not pump |
| Rock | 2:1–4:1, 2–4 dB | Attack 10–30 ms: drums with punch |
| EDM, techno | 2:1–4:1, 1–3 dB, sometimes with intentional pumping | External sidechain from the kick if you want the “breath” |
| Jazz, acoustic, classical | None or 0.5–1 dB | Natural dynamics |
In FL Studio
- Create a “Mix” mixer track, route all buses to it, and route the Mix track to the Master. The chain sits on “Mix”; the Master stays free for metering and for an optional listening limiter.
- Fruity Compressor or Fruity Limiter in COMP mode for the glue; Maximus for listening limiting; Fruity Soft Clipper for the clipper. Typical external plugins: SSL Bus Compressor, Cytomic The Glue, Kush Bus, Slate Virtual Mix Rack, FabFilter Pro-C (Bus style).
- For the export intended for mastering, turn off the listening limiter and leave the glue and saturation if they are part of the sound.
Headroom
- Mix bus peak before the listening limiter: −6/−3 dBFS.
- Mix loudness before mastering: typically −20/−14 LUFS depending on genre and density; a louder mix limits the mastering choices.
Common mistakes
- Adding the chain at the last moment: the balance changes.
- Glue compression with 5–6 dB of reduction: a pumping, flat mix with nothing left for mastering.
- Heavy limiter on the mix bus in the export for mastering.
- No HP in the compressor's sidechain: the kick drives the whole mix.
- Mix bus plugins used to fix problems that live in the tracks.
Starting settings
| Parameter | Value | Why |
|---|---|---|
| Glue | Ratio 2:1, attack 10–30 ms, auto release, 1–3 dB GR | Cohesion without pumping. |
| Sidechain HP | 60–120 Hz | The bass does not drive the compressor. |
| Saturation | 1–2 dB of drive | Density. |
| Mix bus peak | −6/−3 dBFS | Headroom for mastering. |
| Listening limiter | 1–3 dB, turned off in the export for mastering | Listen close to the final loudness without printing it. |
| When to insert | Within the first quarter of the mix | Decisions made through the chain. |
Frequencies to watch
| Range | What to do |
|---|---|
| Below 60–120 Hz (sidechain) | HP in the glue sidechain: kick and 808 do not make the mix pump. |
| 30–60 Hz | Optional light “Pultec” weight boost. |
| 10–12 kHz | Shelf +0.5/+1.5 dB of air. |
Example chain
| Step | Tool | Settings | Why |
|---|---|---|---|
| Corrective EQ | Fruity Parametric EQ 2 | HP 20–25 Hz, slight tilt | Cleanup. |
| Glue | Fruity Compressor / SSL Bus / The Glue | 2:1, 1–3 dB | Cohesion. |
| Saturation | Tape / console / transformer | 1–2 dB drive | Character. |
| Color EQ | Pultec / Pro-Q | Air +1 dB | Brightness. |
| Listening limiter | Maximus / Pro-L | 1–3 dB, listening only | Loudness reference. |
How to check the result
- Peak of the mix exported for mastering between −6 and −3 dBFS.
- Integrated loudness of the mix for mastering between −20 and −14 LUFS (dense genres up to −12).
- Crest factor of the unmastered mix at least 10–12 dB in acoustic genres and 8–10 dB in pop and electronic music.
- Chorus short-term 2–5 LU above the verses: bus compression must not flatten the sections.