Definition
A mastering chain is the ordered sequence of processors applied to the stereo mix (or to stems) to produce the master: tonal balance, dynamics control, width, loudness and technical compliance of the file. Order matters because nonlinear processors are not commutative: an EQ before the compressor changes what the compressor reacts to; a limiter followed by an EQ no longer guarantees the ceiling.
Reference order:
- Preparation: input level, DC offset removal, editing of the start and end.
- Corrective EQ: resonances, rumble, excess in a band.
- Compression: low-ratio bus compression and, if needed, multiband compression.
- Tonal EQ and saturation: color and density.
- Stereo image: Mid/Side moves, centering of the bass.
- Clipper: trimming the shortest peaks.
- Limiter in true peak mode: final loudness and ceiling.
- Sample rate conversion (if the delivery format requires it), followed by a new true peak check.
- Bit depth reduction with dither: always the last process.
Compare every stage with the bypass at matched loudness, because even a 0.5 LU difference skews your judgment.
Parameters and units
| Stage | Typical amount |
|---|---|
| Corrective EQ | cuts −1/−3 dB, Q 2–6 |
| Bus compression | ratio 1.5:1–2:1, GR 1–2 dB, attack 10–30 ms |
| Multiband | GR 1–3 dB per band |
| Tonal EQ | ±0.5–2 dB, Q 0.5–1 |
| Saturation | THD < 1% |
| M/S | Side high-pass 80–150 Hz; Side ±1–2 dB |
| Clipper | 0.5–1.5 dB |
| Limiter | 1–4 dB, ceiling −1.0 dBTP |
| Dither | TPDF at 16 bit; optional at 24 bit |
Musical function
The chain turns the mix into a file that sounds consistent on every system and next to other tracks: it corrects the imbalances the mix did not resolve, brings loudness to the level of the genre and the destination, controls peaks and prepares the delivery format. A well-made mix calls for a short chain; heavy moves in mastering point to a problem that should be fixed in the mix.
Practical example
Incoming pop mix and measurements after each stage:
| Stage | Integrated loudness | True peak | PLR | LRA |
|---|---|---|---|---|
| Mix | −15.8 LUFS | −4.2 dBTP | 11.6 dB | 6.8 LU |
| Corrective EQ (−2 dB at 250 Hz) | −16.1 LUFS | −4.4 dBTP | 11.7 dB | 6.8 LU |
| Bus compression (2:1, GR 1.5 dB) + makeup | −15.0 LUFS | −3.8 dBTP | 11.2 dB | 6.3 LU |
| Tonal EQ and saturation | −14.6 LUFS | −3.5 dBTP | 11.1 dB | 6.3 LU |
| Clipper (1 dB) | −13.9 LUFS | −3.9 dBTP | 10.0 dB | 6.2 LU |
| Limiter (+4.5 dB, ceiling −1.0 dBTP) | −9.5 LUFS | −1.0 dBTP | 8.5 dB | 5.9 LU |
The master reaches −9.5 LUFS with a PLR of 8.5 dB and an LRA of 5.9 LU: commercial pop density with the transients and the shape of the song preserved.
Common mistakes
- Placing processors after the limiter without re-measuring the true peak.
- Applying dither before the limiter or more than once.
- Using many processors out of habit: every stage adds phase shift, noise and artifacts.
- Judging without loudness compensation.
- Chasing meter numbers instead of comparing with the reference by ear.
- Receiving a mix with a limiter already on it and limiting it a second time.
- Converting the sample rate after the limiter without a new peak check.
How to check it
- App analysis: analyze mix, master and reference in the same comparison. Read Integrated loudness (BS.1770), Maximum short-term (3 s), Maximum momentary (400 ms), Loudness Range (EBU 3342), True peak (×4, BS.1770), PLR, PSR, Crest factor, Inter-sample peaks above 0 dBFS, Clipped sections, the energy per band, Side / Mid, Stereo correlation and Drop when summed to mono.
- Criteria: loudness within ±1 LU of the reference, PLR within ±1.5 dB, bands within ±2–3 dB, true peak ≤ −1 dBTP, no overs and no clipping.
- Loudness-matched comparison: lower the master to the loudness of the mix to check that mastering improved the sound and not just the volume.
Starting settings
| Parameter | Value | Why |
|---|---|---|
| Bus compression | 1.5:1–2:1, GR 1–2 dB | Cohesion without losing dynamics. |
| Clipper | 0.5–1.5 dB | Reduces the limiter's workload. |
| Limiter | 1–4 dB, ceiling −1.0 dBTP | Final loudness with controlled peaks. |
| PLR drop mix → master | 2–4 dB | Density achieved without crushing the transients. |
| LRA drop mix → master | ≤ 1–2 LU | Shape of the song preserved. |
| Dither | last process, applied only once | Correct bit depth reduction. |
Example chain
| Step | Tool | Settings | Why |
|---|---|---|---|
| Preparation | Trim / utility | Input peaks −6/−3 dBFS | Headroom for the following stages. |
| Corrective EQ | FabFilter Pro-Q / Fruity Parametric EQ 2 | Cuts −1/−3 dB | Fixes imbalances before dynamics. |
| Compression | Bus compressor / multiband | 2:1, GR 1–2 dB | Cohesion and band control. |
| Color | Tonal EQ, saturation | ±0.5–2 dB, THD < 1% | Final character. |
| Image | M/S EQ or imager | Side HP 80–150 Hz | Centered bass and controlled width. |
| Clipper | Clipper with oversampling | 0.5–1.5 dB | Trimming of short peaks. |
| Limiter | FabFilter Pro-L 2 / Ozone Maximizer | Ceiling −1.0 dBTP, true peak | Loudness and compliance. |
| Dither | TPDF dither from the limiter or the export | 16 bit only | Bit depth reduction without distortion. |
How to check the result
- Master true peak ≤ −1.0 dBTP and Inter-sample peaks above 0 dBFS = 0.
- Integrated loudness within ±1 LU and PLR within ±1.5 dB of the genre reference.
- Master LRA no more than 2 LU below that of the mix.
- Energy per band within ±2–3 dB of the reference; width of the Sub and Bass bands ≤ −15 dB.