8D Audio Test

An 8D audio test plays a moving sound source around your head so you can hear how a headphone pair renders the orbit. This page pans a continuous 440 Hz sine in a circle with the Web Audio API and prints the live angle, position and pan value. Nothing is uploaded, and nothing plays until you start it.

How to use it

The orbit is driven from a single panel: transport bar at the top, live readouts above the map, direction and speed controls below it.

1. Set the output and level first. In the transport bar, select your headphones in the output device picker, move the volume slider to a low comfortable setting, and check the sample-rate readout, which shows your interface rate, typically 48.0 kHz.
2. Press Start Orbit. A 440 Hz sine fades in over 40 ms to 0.25 linear gain, which is -12 dBFS, and the emitter begins moving clockwise at the default 30°/s.
3. Watch the readout block. Angle, Position, Pan, Speed and Period update every animation frame. Pan is the sine of the angle, so it reads +1.00 (Right) at 90° and -1.00 (Left) at 270°.
4. Reverse the direction. The Clockwise and Counterclockwise buttons flip the sign of the rotation without interrupting the tone, which is the fastest way to compare the two sides.
5. Change the speed. Drag the slider between 5 and 120°/s, or press a preset: 15, 30, 60 or 90°/s. The period readout follows period = 360 / speed, so 30°/s takes 12.0 s per revolution and 5°/s takes 72.0 s.
6. Follow the orbit map. The moving dot marks the emitter position, the head silhouette shows the listener orientation and the dashed line connects the two.
7. Stop with Stop Orbit or the transport Stop. Gain ramps down over 40 ms and the oscillator is torn down, so nothing keeps running in a background tab.

What the 8D label means

Commercial 8D tracks are binaural renders rather than a channel format. A mono or stereo source is processed with head-related transfer functions (HRTFs) that encode interaural level differences, interaural time differences and pinna filtering, then blended with reverb and early reflections so the source seems to move around a room and sometimes behind the listener. Playback is stereo by definition, and the illusion depends on each ear receiving a separate signal. That makes 8D audio a production decision you can audition, but it is not a measurement of your headphones.

This page renders the orbit geometry in a reduced form: one mono sine, one StereoPannerNode, and a pan value equal to sin(angle), smoothed with a 15 ms time constant. What you are testing is whether your headphones and your ears track a continuously changing interaural level difference smoothly, without dropouts, sticking or a collapsed center. For a fuller explanation of the effect, read what 8D audio is.

Pan positions and what each one should sound like

The Web Audio equal-power panning law keeps total power roughly constant as the source crosses the stereo field. The levels below are digital gains applied to the synthesised sine, not sound pressure.

Angle	Position readout	Pan value	Left / right gain	Expected headphone image
0°	Front	0.00	-3.0 dB / -3.0 dB	Centered between the ears
45°	Front-Right	+0.71	-12.8 dB / -0.2 dB	Strongly right, still present on the left
90°	Right	+1.00	Silent / 0.0 dB	Hard right
135°	Rear-Right	+0.71	-12.8 dB / -0.2 dB	Strongly right again
180°	Rear	0.00	-3.0 dB / -3.0 dB	Centered again, with no rear cue
270°	Left	-1.00	0.0 dB / Silent	Hard left
315°	Front-Left	-0.71	-0.2 dB / -12.8 dB	Strongly left

The table contains the honest limitation of the demo: with amplitude panning alone, 0° and 180° produce the identical signal. The graphic marks “Rear”, but nothing in the audio differs from “Front”. Front/back and elevation cues need HRTFs, interaural delays or spectral shaping that this test does not generate.

Orbit diagnostics

Listen for four things while the emitter rotates. First, the center crossing: the tone should glide through the middle without a dip or a lurch. Second, symmetry: maximum right and maximum left should be equally loud, so if one side is weaker, check the headphone fit, the cable and the operating-system balance slider. Third, continuity: clicks, stutters or dropouts usually come from the browser losing focus, Bluetooth buffering or an aggressive power-saving mode, not from the pan algorithm. Fourth, the mono check: if the orbit sounds like a volume knob rather than movement, disable Mono Audio in your accessibility settings and any “spatial audio” or “3D surround” upmixer on your headphones, because those processors widen or fold the stereo image before it reaches your ears.

Accuracy, limits and troubleshooting

• This is a spatial-audio demo, not a localization measurement. It cannot score where you heard something or how accurately you placed it. Use the sound localization test for that.
• Headphones are required. On loudspeakers, acoustic crosstalk sends both channels to both ears and the 360° orbit collapses into a level pan.
• Rear is not encoded. Front and rear are both full-center amplitude; the position readout labels the angle on screen, not a perceptual claim.
• Levels are digital. -12 dBFS at the oscillator says nothing about the dB SPL at your eardrum; that depends on the volume slider, the OS mixer and headphone sensitivity.
• Bluetooth can break the illusion. Codecs that share stereo information between channels, plus buffering jitter, smear hard pans and can add audible modulation.
• Browser restrictions apply. Audio starts only after a user gesture, some browsers suspend the audio context in a background tab, and iOS needs the ringer switch off for Web Audio to be audible.
• The tool does not measure polarity, frequency response or distortion. If you suspect those faults, run a channel or THD test first.

Related tools

• Binaural Beats — Compare a static two-tone binaural presentation with this moving amplitude orbit.
• Sound Localization Test — Score left, right and behind localization instead of watching a visual orbit.
• Headphone Test — Confirm channel assignment and balance before you judge a spatial effect.

Aliases covered on this page: 8d audio test, 8d audio check, binaural audio test, spatial audio test, and headphone spatial test.