DAW-Agnostic DIY Split EQ with Metaplugin (and Oeksound Spiff)

#Audio#Plugins#Eventide Split EQ#Metaplugin#Oeksound Spiff#Transient Designer#Mixing#Mastering

In a previous post and video, I explored creating a DIY “Split EQ” effect within Reaper, allowing separate processing of transient and tonal parts of audio using a standard transient designer. While powerful, that method relied heavily on Reaper’s specific routing capabilities.

This post covers the follow-up video where I recreate this functionality using DDMF Metaplugin, making the setup DAW-agnostic. We also test Oeksound Spiff as an alternative splitting engine, potentially getting closer to the behaviour of dedicated plugins like Eventide SplitEQ.

Watch the video walkthrough here:

Why Metaplugin? Portability!

DDMF Metaplugin is a plugin that hosts other plugins, allowing you to build complex effects chains with intricate routing, all within a single plugin instance that can be loaded in almost any DAW. This overcomes the DAW-specific limitations of the previous Reaper FX Chain method.

The Metaplugin Signal Flow

The logic inside the Metaplugin patch mirrors the concept from the previous video:

  1. Input & Split: The incoming stereo signal enters the Metaplugin environment.
  2. Tonal Stream: The signal is sent to a transient shaper plugin (like the free Kilohearts Transient Shaper) with its ‘Attack’ turned fully down. The output of this plugin is our Tonal stream.
  3. Transient Stream: The Tonal stream’s polarity is inverted. This inverted Tonal stream is then mixed (summed) with the original, clean input signal. The result of this sum (Original + (-Tonal)) effectively isolates the Transient stream.
  4. Processing: The separated Transient and Tonal streams are routed internally within Metaplugin to a multi-channel capable EQ plugin (like FabFilter Pro-Q, configured to process the different streams independently – e.g., Transient on L/R, Tonal on Surround L/R).
  5. Mixing: After EQ (or other processing), the Transient and Tonal streams are summed back together into a final stereo output.
  6. Utilities: The Metaplugin patch includes handy A/B switches configured as mute buttons, allowing easy soloing of either the Transient or Tonal path for monitoring during setup.

This Metaplugin setup reliably separates the streams and ensures that, regardless of the transient shaper settings, the summed output perfectly nulls with the input if no EQ/processing is applied.

Exploring Oeksound Spiff as the Splitting Engine

The most exciting part of this follow-up was testing Oeksound Spiff in place of the standard transient shaper. Spiff uses a more sophisticated, adaptive FFT-based method for detecting and processing transients, which is conceptually closer to how dedicated Split EQs might operate.

  • A Metaplugin preset allows switching between the Kilohearts Transient Shaper and Spiff as the core splitting plugin.
  • Spiff was configured for maximum sensitivity and resolution to capture as much transient detail as possible (see video for specific settings). The same logic (Plugin Output = Tonal, Original - Tonal = Transient) was applied.
  • The video includes comparisons listening to the isolated Transient and Tonal parts generated by Kilohearts, Spiff, and the original Eventide SplitEQ, as well as the audible effect of applying a 5kHz transient boost with each method. As expected, Spiff’s separation sounded somewhat different and arguably closer in character to SplitEQ’s results compared to the basic transient shaper method.

Updated Reaper FX Chain (Briefly)

For users of the original Reaper chain, the video also demonstrates an updated version. This revised chain achieves the same (Original - Tonal = Transient) logic but uses only one instance of the transient shaper plugin, relying on more intricate multi-channel pin routing and Reaper’s built-in utility plugins (Polarity Control, Downmixers) to perform the necessary signal subtractions and routing before feeding the Pro-Q plugin.

Conclusion

Using Metaplugin provides a robust and portable way to implement this DIY transient/tonal splitting technique in any DAW. Furthermore, integrating an advanced tool like Oeksound Spiff demonstrates how the quality of the separation can be improved, blurring the lines between this DIY approach and dedicated commercial plugins. While requiring specific tools (Metaplugin, Spiff/Pro-Q for advanced use), these methods offer deep control over audio dynamics and tone.