Multichannel Audio Verification Suite

Verifying decodeAudioData(), Web Audio multichannel routing, and direct <audio> element playback. Each card below is a generated 16-bit WAV with a distinct sine tone per channel (220 Hz + 110 Hz × channel index).

Why the original test was silent / reported 2 channels:

MediaElementAudioSourceNode.channelCount is 2 by W3C spec: the channelCount property on an AudioNode specifies how inputs to that node are up/down-mixed. Because source nodes have 0 inputs, channelCount defaults to 2 and has no effect on output channels. The actual channel count is found via decodeAudioData() or by querying output pin connections.
createMediaElementSource() detaches native speaker output: calling createMediaElementSource(audio) redirects audio away from standard browser playback into the Web Audio graph. If the context is suspended (autoplay policy) or not routed to destination, the player goes silent.
Discrete stereo downmixing on macOS: for channel counts > 6, the Web Audio spec mandates discrete routing. Stereo headphones/speakers only receive channels 0 & 1; channels 2+ are dropped unless mixed down to stereo.

Optional: drag & drop your own WAV / multichannel audio file here, or to test your custom assets.

Multichannel Audio Verification Suite

Custom file

Test cards