SPAZIAL EQ M/S — Tips for Mixing and Wider Soundstage


What mid/side (M/S) processing does — short primer

M/S processing decodes stereo audio into two components:

  • Mid — the sum of left and right (L+R), representing centered material.
  • Side — the difference (L−R), representing stereo information and spatial content.

Applying EQ separately to these components allows you to:

  • Tighten or broaden a mix without changing overall panning.
  • Reduce masking between vocals and guitars by attenuating competing frequencies in the mid channel.
  • Sculpt reverb and ambience in the side channel without affecting the vocal presence.

Plugin signal flow and interface overview

Most SPAZIAL EQ M/S layouts follow a consistent logic (actual control names may vary by version):

  • Input/Output meters: show level before and after processing.
  • M/S Mode switch: toggles between stereo (L/R) and mid/side operation.
  • Band sections (typically multiple bands): each band usually includes:
    • Type (bell, shelf, high/low pass)
    • Frequency selector
    • Gain control (boost/cut)
    • Q (bandwidth)
    • M/S selector per band — choose whether the band affects Mid only, Side only, or Both.
  • Global controls:
    • Stereo Width or Mid/Side Balance knob — adjust relative level of side vs mid.
    • High-pass and low-pass global filters (often available).
    • Linear phase / minimum phase toggle — affects phase behavior and latency.
    • Solo/Listen for Mid or Side — isolate components to hear adjustments.
  • Bypass and preset management.

If SPAZIAL EQ M/S includes spectrum displays and correlation meters, use them to visualize how changes affect tonal balance and stereo correlation.


Key controls and how to use them

  • M/S Mode switch: Engage to work in the mid/side domain. Use the Solo/Listen buttons to audition Mid or Side while making changes.
  • Band M/S routing: Assigning a band to Mid targets center elements; assigning to Side affects reverb/ambience and stereo accents.
  • Q (bandwidth): Narrow Q values for surgical cuts (e.g., resonance taming), wider Q for musical shaping.
  • Linear vs Minimum phase: Use linear phase for mastering or when preserving phase relationships is critical; minimum phase for lower CPU and fewer pre/post-ringing artifacts in typical mixing tasks.
  • Stereo Width knob: Increasing width raises the level of side content relative to mid — use sparingly, +2 to +6 dB can widen subtly; extreme values can make mixes unstable or mono-incompatible.

Practical workflows and step-by-step examples

Below are common tasks with stepwise settings and rationale. Start conservative — small gains/cuts are usually better.

  1. Tightening a mix (control low-mid muddiness)
  • Switch to M/S mode.
  • Solo Mid channel and sweep a low-mid range (150–400 Hz) with a moderate Q.
  • If buildup exists, apply a cut of −1.5 to −4 dB with Q around 0.8–1.5.
  • Uns solo and A/B with bypass to confirm impact on fullness without hollowing.
  1. Making vocals clearer without touching reverb
  • Assign a narrow bell on the Mid channel around 2.5–5 kHz for presence; small boost +1 to +2.5 dB, Q ~1.
  • Alternatively, cut competing Mid content around 300–600 Hz by −1.5 to −3 dB.
  • If reverb sounds too bright or sibilant, switch a high shelf on the Side channel down −1 to −3 dB above 5–8 kHz.
  1. Widening ambience and room sound
  • Target Side channel: subtle high-shelf boost of +0.8 to +2 dB above 8–12 kHz for air.
  • Use low-shelf on Side to slightly reduce low-end (−1 to −3 dB below 120–250 Hz) to avoid muddy widening.
  • Increase Stereo Width by small increments; monitor mono compatibility and phase correlation.
  1. Cleaning stereo guitar bed
  • In Side: use narrow cuts to tame resonances or scratchy frequencies that distract (2–6 kHz).
  • In Mid: gentle low cut around 60–100 Hz if low rumble exists.
  • Pan imaging stays intact because you’re operating on mid/side components rather than individual channels.
  1. Mastering dose: subtle stereo correction
  • Linear phase mode.
  • Use very gentle moves: Mid low-end shelf +0.5 dB around 40–80 Hz if center bass is lacking; Side top-end shelf +0.5–1 dB above 8–12 kHz for added sparkle.
  • If stereo image is lopsided, use the Stereo Width or adjust Side gain by ±0.5–1 dB.

These are starting points — always use ears and context rather than fixed numbers.

  • M/S Mode: ON for imaging tasks; OFF for standard stereo EQ.
  • Band gain (surgical): ±0.5 to ±4 dB. In mastering, stick to ±0.2 to ±1 dB.
  • Q values:
    • Surgical cut/boost: Q 4–10
    • Broad musical shaping: Q 0.5–1.5
  • Low cut (Mid): 20–40 Hz (gentle) to remove subsonic rumble.
  • High shelf (Side): +0.5–2 dB at 8–12 kHz for air.
  • Stereo Width: 0 to +6 dB typical; avoid > +8 dB without reason.

Troubleshooting common issues

  • Phasey or hollow sound after EQ:
    • Check minimum vs linear phase; switching to minimum phase can sometimes sound more natural in mixes.
    • Reduce extreme boosts; try cutting opposing frequencies instead.
  • Mono compatibility problems:
    • Temporarily sum to mono while adjusting Side boosts; if elements vanish or sound odd, reduce Side gain or adjust Mid.
  • Excessive noise when widening:
    • Apply low cut to Side below 120–250 Hz to prevent boosting noise and rumble.
  • CPU/latency concerns:
    • Disable linear phase or reduce analysis resolution for lower latency during tracking.

Example preset bank (practical presets)

  • Vocal Clarity (Mid-focused)
    • Mode: M/S On
    • Band 1 (Mid): Bell 350 Hz cut −2.5 dB Q 1.2
    • Band 2 (Mid): Bell 3.2 kHz boost +1.8 dB Q 1.0
    • Side: no change
  • Airy Stereo (Side-focused)
    • Side: high shelf +1.2 dB @10 kHz
    • Side: low shelf −2 dB @180 Hz
    • Stereo Width +3 dB
  • Tight Bass (Master)
    • Mid: low shelf +0.6 dB @60 Hz
    • Side: low shelf −3 dB @120 Hz
    • Linear phase On
  • De-Boxing (reduce boxiness in mid)
    • Mid: bell 250 Hz −3 dB Q 1.4
    • Side: slight high shelf +0.8 dB @9 kHz
  • Wide Reverb Control
    • Side: bell 4 kHz cut −1.5 dB (tame sibilant reverb)
    • Side: high shelf +1 dB @12 kHz (add air)
    • Mid: no change

Listening tests and verification

  • Always A/B with bypass and reference tracks.
  • Check in mono periodically (Ctrl/Command + click stereo width or use a mono plugin).
  • Use phase correlation meter — aim for mostly positive correlation; large negative spikes indicate mono incompatibility.
  • Solo Mid and Side to confirm surgical changes are affecting intended material.

Final notes and best practices

  • Think of M/S EQ as surgical spatial sculpting: small changes produce big perceived differences.
  • Prioritize subtraction (cuts) over heavy boosts when possible.
  • Use linear phase for mastering or when inter-band phase relationships matter; expect higher latency and CPU use.
  • Preserve the musical intent — widening or de-centering elements can change emotional focus.

If you want, I can convert any of the example presets into exact parameter lists for a specific DAW/plugin format, or create a shorter cheat-sheet you can print and keep at your mixing station.

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