Mastering & Mix Bus EQ Frequencies: Mid/Side Balance & LUFS Headroom (20 Hz β 20 kHz)
On the stereo master bus, every 1 dB adjustment impacts all instruments simultaneously. Mastering EQ is not about fixing broken individual tracksβit is about optimizing tonal balance, maximizing LUFS loudness efficiency, and sculpting three-dimensional stereo width.
Direct Acoustic Data & Engineering Fact
Mastering EQ uses broad, low-Q adjustments (Β±0.5 to Β±2.0 dB) and Mid/Side filtering. Apply a linear-phase high-pass filter at 22β28 Hz in the Mid channel and 90β120 Hz in the Side channel to mono the sub-bass, dip 260 Hz (-1.0 dB) for headroom, and lift 12 kHz (+1.5 dB) on the Sides.
Surgical EQ Recommendations Table
| Band / Filter | Frequency | Q Factor | Gain | Acoustic Purpose |
|---|---|---|---|---|
| Sub-Sonic Protection | 24 Hz | 24 dB/oct | 0 dB | Reclaim 1β2 dB of true-peak limiter headroom from inaudible rumble. |
| Side-Channel Bass Cut | 110 Hz (Side) | 12 dB/oct | 0 dB | Ensure 100% mono compatibility for club subwoofers and vinyl. |
| Box/Mud Cleanup | 275 Hz | 1.618 | -1.2 dB | Uncover mix clarity and separation across all stems. |
| Stereo Air Lift | 14 kHz (Side) | 0.618 | +1.5 dB | Create wide, expensive commercial top-end sheen. |
Mix Engineer Practical Strategy
Use FIBONACCI EQ with golden-ratio Q curves (Q = 0.618 or 1.618) so phase shifts remain musical. High-pass the Side channel below 110 Hz (or use PHASOR's Mono-Bass Crossover) so sub energy focuses 100% in the center.
Frequency Masking & Arrangement Clashes
Excessive energy at 200β350 Hz triggers master bus limiters prematurely, causing pumping and distortion before you reach -8 to -9 LUFS integrated loudness.
Suggested VST DSP Plugins for this Task
Frequently Asked Questions
Should I cut below 20 Hz or 30 Hz when mastering?
A gentle 18β24 dB/oct filter at 22β26 Hz removes wasted sub-sonic energy while avoiding resonant phase ringing at 40β50 Hz.
Why use Mid/Side EQ on the master bus?
Mid/Side EQ lets you keep the sub-bass and lead vocal tight in the center (Mid) while boosting airy highs (10β16 kHz) exclusivamente on the stereo edges (Side).
More Acoustic Frequency Guides
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