Audio Signal Flow

This SOP defines the standards and best practices for designing, verifying, documenting, and maintaining audio signal flow for all MP/RV events. Clear and consistent signal flow ensures reliable operation, fast troubleshooting, and predictable results across FOH, monitors, and broadcast feeds.

If you cannot clearly trace the signal path, the system is not ready.

Purpose

  • Ensure clean, logical signal paths from source to output.

  • Prevent routing errors, feedback loops, and unintended processing.

  • Standardize how signal flow is designed and documented.

  • Enable fast troubleshooting under show conditions.

  • Support consistent workflows across operators and consoles.

Who This SOP Is For

  • Audio leads / A1s

  • Monitor engineers

  • Audio technicians

  • Warehouse staff assisting with system prep

  • Project Managers overseeing audio scope

  • Authorized freelancers

Anyone configuring routing or patching must understand this SOP.

Scope

This SOP applies to:

  • Microphone and line-level inputs

  • Digital and analog stage boxes

  • FOH and monitor consoles

  • Submixes and matrices

  • System processing (DSP)

  • Amplifiers and powered speakers

  • Recording and broadcast feeds

Manufacturer-specific routing details are documented separately.

Signal Flow Principles

All audio systems must follow these principles:

  • Source → Control → Processing → Output

  • Avoid unnecessary conversions.

  • Maintain proper gain structure at each stage.

  • Keep routing as simple as possible.

  • Document any deviations from standard flow.

Complexity increases failure risk.

Standard Signal Flow Overview

Typical MP/RV signal flow:

  1. Source (microphone, DI, playback)

  2. Stage cabling

  3. Stage box / digital snake

  4. Console input

  5. Channel processing

  6. Mix buses / matrices

  7. System processing (DSP)

  8. Amplifiers or powered speakers

  9. Loudspeakers

Every step must be verified.

Input Stage

  • Verify correct source connection.

  • Confirm phantom power where required.

  • Set input gain conservatively.

  • Label channels clearly and consistently.

Input errors propagate downstream.

Console Routing

  • Confirm channel-to-bus routing.

  • Verify aux sends for monitors.

  • Confirm matrix routing for fills and delays.

  • Avoid duplicate or unintended routing paths.

Routing mistakes cause feedback and confusion.

Monitor Signal Flow

  • Maintain separate monitor mixes when possible.

  • Verify pre/post-fader settings.

  • Label mixes clearly.

  • Avoid sharing monitor paths unintentionally.

Monitor clarity affects performer confidence.

System Processing

  • Apply processing intentionally.

  • Avoid stacking unnecessary EQ or dynamics.

  • Maintain consistent crossover and alignment settings.

  • Document DSP configurations.

Processing should serve coverage and clarity.

Amplification & Output

  • Verify amplifier input assignments.

  • Confirm speaker polarity.

  • Match amplifier channels to speaker loads.

  • Avoid overdriving outputs.

Output errors are difficult to correct mid-show.

Broadcast & Recording Feeds

  • Define broadcast and recording tap points clearly.

  • Avoid changing levels mid-show.

  • Communicate feed type (pre/post processing).

  • Test feeds thoroughly.

External feeds require extra care.

Verification & Testing

  • Line-check every input.

  • Verify signal through each stage.

  • Test all mixes and outputs.

  • Walk the signal path logically during testing.

Testing confirms theory.

Documentation

  • Maintain input lists and patch sheets.

  • Document: - Channel assignments - Routing decisions - Special processing

  • Save console files with notes.

Documentation supports continuity.

Changes During Show

  • Avoid structural routing changes mid-show.

  • If changes are required: - Communicate clearly - Document immediately

  • Restore standard routing post-show.

Unplanned changes increase risk.

Troubleshooting Signal Flow

When issues occur:

  • Start at the source.

  • Follow the signal path step-by-step.

  • Verify each stage before moving on.

  • Avoid random adjustments.

Systematic troubleshooting saves time.

Roles & Responsibilities

Audio Leads / A1

  • Design and approve signal flow.

  • Verify routing and processing.

  • Document system configuration.

Audio Technicians

  • Assist with patching and testing.

  • Follow approved signal paths.

  • Report inconsistencies.

Warehouse Staff

  • Support prep and documentation.

  • Maintain standard templates.

Project Managers

  • Understand signal flow implications for scope and staffing.

Quality Control

  • Signal flow verified before doors.

  • Documentation complete.

  • Changes tracked and reviewed.

  • Issues addressed post-show.

Clear signal flow prevents show failures.