Metric Halo Sonic EQ — Free Download

Purpose and Heritage

Sonic EQ is a digital mastering equalizer originally developed by Dr. James A. Moorer for Lucasfilm’s SoundDroid project and later expanded for Sonic Solutions mastering DAWs. This modern version, available as a native plugin, re-creates the classic Sonic EQ processing for contemporary digital audio workstations.

The plugin is a six-band fully parametric equalizer with each band supporting filters from second to eighth order, using a low-noise 64-bit state-space structure with the core Sonic EQ coefficients. It is designed to deliver a full, sweet, and powerful musicality while providing precision control over filter ripple, both in-band and out, making it suitable for managing specific frequency content with minimal effect on surrounding program material.

Key Capabilities

Every band offers high-order slopes, allowing steep filtering up to eighth order, which is useful for surgical cuts and precise boosts. The plugin also includes a special band for RIAA encode/decode and digital de-emphasis for vinyl and early digital format transfers. Built-in SpectraFoo spectrum analysis and level metering provide visual feedback, and scalable gain reduction meters help monitor dynamic changes.

The interface features adjustable UI size and disclosable graphs, along with a preset manager for cross-platform presets. This combination of features supports forensic restoration, sound design, mastering, post-production, and recording workflows, allowing users to create complex EQ curves that sound clean and natural.

Workflow and Integration

For mastering engineers, Sonic EQ integrates into existing DAW workflows, whether using hardware DSP or fully native processing. It can be used as a surgical EQ for precision cutting without phase coherency artifacts, or for boosting to a sweet spot, with transient preservation. The built-in analysis tools help visualize the audio spectrum, aiding in making informed EQ decisions.

In post-production, the plugin supports precise frequency management with high-order filters, useful for cleaning dialogue or adding presence. For sound design, the ability to create unusual curves that still sound natural allows for creative shaping. The RIAA and de-emphasis filters are valuable for transfer work, ensuring accurate playback of vinyl or digital sources.

Practical Applications

Practical uses include mastering tracks to achieve a smooth and natural extension, surgical EQ for ridding problematic frequencies without affecting transients, and applying RIAA decode for vinyl transfers or digital de-emphasis for early digital formats. The plugin’s versatility extends to live sound, where its simplicity and power can shape sound quickly.

The high-order filters are especially useful for eliminating rumble or low-frequency noise with steep slopes, while the precision control helps maintain the integrity of the program. The included presets offer starting points for common tasks, and the scalable meters provide visual confirmation of gain changes. This makes Sonic EQ a valuable tool for a wide range of audio professionals.

Key features

• Six-band fully parametric interpolated state-space EQ
• Filters up to eighth order per band
• RIAA encode/decode and digital de-emphasis band
• Built-in SpectraFoo spectrum analysis and level metering
• Scalable gain reduction meters
• Adjustable UI size and disclosable graphs
• Cross-platform preset manager

Best for

Best for mastering engineers, post-production professionals, and sound designers seeking a transparent, high-precision equalizer with steep filter slopes and built-in analysis tools, especially for surgical frequency control and vinyl or digital format transfers.