Mid-Side Matrix Audio Filter

Processes a left/right (L/R) stereo signal internally using a mid/side (M/S) model to control perceived stereo width. This filter redistributes energy between the center (mid) and the sides without changing overall timing or pitch.

This filter is typically used along with a special, dual microphone recording technique.

Mid-Side Matrix is a stereo spatial processing filter. It operates only on stereo material.

Parameters

Width (0 - 100%)

Controls the balance between the mid (center) and side (stereo difference) components.

• 0%
  Side information is removed.
  The result is effectively mono (center only).

• 50% (default)
  Neutral setting.
  Stereo width is preserved as in the original signal.

• >50%
  Side information is amplified.
  Stereo image becomes wider.

• 100%
  Maximum widening.
  Can sound exaggerated or unstable on some material.

Note:
Width changes how wide the sound feels, not how loud it is.

Dry → Wet (0.0 - 100.0%)

Controls the mix between the original stereo signal and the mid-side processed signal.

• 0.0%
  Original audio only.

• 50.0%
  Blend of original and processed audio.

• 100.0%
  Fully Mid-Side processed audio.

This allows subtle widening or narrowing without fully replacing the original stereo image.

Auditory characteristics

• Changes perceived stereo width
• Center content (vocals, dialogue) remains stable
• Side content (ambience, reverb, stereo effects) is emphasized or reduced
• Excessive widening may cause phase issues or poor mono compatibility

Recommended use cases

• Widening music or ambient tracks
• Narrowing overly wide stereo recordings
• Improving focus of dialogue by reducing side content
• Creative stereo effects
• Matching stereo width between clips

Example settings

• Subtle widening (music)

  • Width: 60 - 70%
  • Dry → Wet: 100%

• Strong widening (ambient effects)

  • Width: 80 - 90%
  • Dry → Wet: 100%

• Dialogue focus / near-mono

  • Width: 0 - 20%
  • Dry → Wet: 100%

• Gentle adjustment

  • Width: 70%
  • Dry → Wet: 40 - 60%

Usage notes and tips

• Always check mono compatibility after widening.
• Small changes in Width are often sufficient.
• Use Dry → Wet for fine control rather than extreme Width values.
• Best suited for stereo music and ambience, not centered narration.

Limitations

• Operates only on stereo audio
• Does not create true spatial depth
• Extreme values can introduce phase cancellation
• Not a replacement for surround mixing