SYSTEM ENGINEERING PROTOCOLS
Standard Operating Procedures for Professional Audio Infrastructure, Signal Flow, and Diagnostics.
1. Signal Flow & Gain Staging
Maintaining a high Signal-to-Noise Ratio (SNR) without clipping is the foundation of high-fidelity live sound. The digital realm is unforgiving; unlike analog saturation, digital clipping creates destructive square wave distortion. The "Golden Rule" is to prioritize digital headroom (>12 dB) at the preamp stage to accommodate transient spikes.
Gain Staging Targets vs. Clipping
Values relative to 0 dBFS (Digital Full Scale)
The Optimization Protocol
| Stage | Target / Goal |
|---|---|
| Preamp | -18 to -12 dBFS (Headroom) |
| Processing | Unity Gain (In = Out) |
| Mix Bus | Peak < 0 dBFS |
| System Drive | High Level (> Noise Floor) |
| Amplifiers | Clip AFTER Limiter |
2. Hardware & Wiring
Understanding the physical layer (Layer 0) is critical for system reliability. A reversed polarity on an XLR cable can cancel out bass frequencies, while improper RJ45 termination causes data packet loss in AoIP networks. The industry standard for data wiring is T568B.
RJ45 Pinout (T568B Standard)
Used for Dante, Milan (AVB), and Control Networks.
Analog Pinouts
XLR / TRS
Speakon NL4
3. Network Standards
Audio-over-IP (AoIP) requires logical segmentation. Using Private IP Ranges (RFC 1918) prevents conflicts with public internet traffic. Understanding port usage is essential for configuring firewalls and managed switches to allow clocking (PTP) and audio (Dante) to pass freely.
Critical UDP Ports
Network Scale & Host Capacity
Logarithmic Scale: Number of Usable Hosts per Subnet
4. The Logic Tree
When a signal fails, panic is the enemy. Follow the linear logic path. Do not skip steps. Verify the physical layer first before diving into DSP.
1. Physical Layer
Is the cable plugged in? Is the "Link" light active?
2. Patching (Soft)
Check Dante Controller or Console Soft Patch. Is Source routed to Destination?
3. Gain & Mutes
Is the Preamp up? Is a DCA muted? Is the Master fader up?
4. Clocking & Sync
Are devices locked? Check for red sync lights or audible clicks.
5. DSP & Dynamics
Is a Gate stuck closed? Is a Compressor threshold too low?
6. The Split Test
Inject Pink Noise halfway. Works? Issue is Upstream. Fails? Issue is Downstream.