Test Mono and Stereo Inputs Before Tuning Web Audio Panning

A mono cue and a stereo ambience can respond differently to the same pan setting. Web Audio’s StereoPannerNode has distinct processing for mono and stereo input. A stereo pan can move content from one side into the other. Isolate the signal before trying to diagnose it by ear in a busy mix.

Use two recognizable input layouts

Make a mono pulse. For the stereo test file, put an audible segment only on the left in the first half and only on the right in the second. Leave headroom and use the same output path. Check for anything between decoding and the panner that may already have converted the input channels.

Log the output at center and at both extremes

1. Start at center and log the active intervals on the left and right meters for both inputs.
2. Set pan to each extreme, listen, and note where each half of the stereo file arrives.
3. Bypass the panner and replay. If the bypass also disagrees with the expected channels, investigate the audio graph, output mapping and listening device first.

A mono cue is a useful baseline for movement. If the ambience is intentionally wide, decide how much of that width the game should retain before moving it. Record the input channels, pan positions and monitoring setup in the acceptance notes.

Prepare a sample with the Tooliva tool, then run the checks in the target environment.