Broadcast Audio Chain Verification

TL;DR

Broadcast audio chains are long and complex: microphone → preamp → console → processing → codec → STL → transmitter → receiver. A problem anywhere in the chain degrades the signal, and finding the faulty link requires systematic measurement. SonaVyx's transfer function analysis can verify each segment by comparing input to output at every stage.

Segment-by-Segment Verification

The key insight is measuring each segment individually using transfer function, then comparing against a known reference. A transparent segment shows flat magnitude (±0.5 dB) and linear phase across the operating bandwidth.

Microphone and preamp. Feed a calibrated test signal into the mic preamp via a test oscillator or SonaVyx's signal generator. Capture the preamp output with a line-level input. Check: frequency response 20 Hz - 20 kHz within ±1 dB, noise floor below -60 dBu, no clipping at +4 dBu output.
Console path. Route the test signal through the console channel strip with all EQ and dynamics bypassed. The transfer function should be flat within ±0.5 dB. Any deviation indicates a faulty channel, gain staging error, or accidentally engaged processing.
Processing chain. Measure through each processor (compressor, limiter, EQ) individually. Document the transfer function of each unit at its operating settings. This creates a baseline for detecting when settings drift or equipment degrades.
Codec/STL path. For digital links, measure the codec's transfer function by feeding a known signal in and capturing the decoded output. Lossy codecs (AAC, MP3) introduce frequency-dependent artifacts that transfer function reveals.

Full-Chain Verification

After verifying individual segments, measure the complete chain. Open SonaVyx Transfer Function mode and inject a reference signal at the mic preamp input while capturing at the final output stage. The complete chain transfer function should match the sum of individual segment measurements. Discrepancies indicate an interaction between stages (impedance mismatch, ground loop, etc.).

Periodic Maintenance Checks

Store chain measurements in SonaVyx's Venue system (create a venue for the studio/station). Compare monthly measurements against the baseline. A 2 dB shift in the 2-4 kHz range might indicate a degrading capacitor in a preamp or a failing codec.

Common Mistakes

Measuring the complete chain without checking segments. A flat overall response can mask compensating errors: a +3 dB boost in one stage cancels a -3 dB cut in another, hiding two problems.
Ignoring phase. A codec might have flat magnitude but introduce phase distortion that affects stereo imaging and temporal quality.
Not documenting baseline settings. Measurement is only useful with a reference. Document every gain setting, processing parameter, and routing when you establish the baseline.

Tool Bridge

Use SonaVyx Transfer Function mode to measure each audio chain segment. Store baselines in Venues for periodic comparison.