Stereo room check
Speaker Test
Run a speaker sound test for left and right routing, phantom center, polarity, phase, and useful frequencies.
Start at low volume. No audio leaves your device.
Speaker system check
ReadyOut-of-phase audio often sounds diffuse or weak in the center when you sit equally between two speakers.
How to test speakers and phase
Match the distance from your head to each speaker before comparing levels.
Play Left and Right and identify the cabinet that actually produces each tone.
Listen for a stable center in phase and a diffuse image out of phase.
A speaker test must account for both channel routing and the room. Unlike headphones, each speaker reaches both ears and reflects from walls, furniture, and the desk. The useful question is not whether the unused ear is silent. It is whether the correct physical cabinet plays, whether the two speakers create a stable center, and whether their polarity works together.
Begin with a moderate midrange frequency and use the Left and Right controls. Trace any unexpected result from browser to output. An audio interface may call its channels 1 and 2, an amplifier may use A and B speaker groups, and passive speaker cables may cross behind furniture. Correct these physical assignments before applying software balance.
Build a stable stereo image
The Stereo control sends the same tone to both channels in phase. From a centered seat, the sound should form a phantom source midway between the cabinets. If it pulls strongly to one side, compare distance, toe-in, amplifier gain, and nearby reflective surfaces. Moving your chair only a few centimeters can clarify whether the issue follows the room or remains fixed.
A soundbar, smart speaker pair, or home theater receiver may apply virtual surround, delay, room correction, or bass management. Those systems are not necessarily wrong when they sound wider than two conventional speakers. Disable processing for a baseline, then restore one feature at a time.
Understand the phase comparison
In phase means both speaker cones receive matching polarity for the test signal. Out of phase reverses one channel inside the browser. The out-of-phase button should usually make the center less stable and can reduce low-frequency energy at the listening position. This contrast helps you learn the symptom of a reversed speaker connection.
If the In phase control already sounds diffuse while Out of phase becomes focused, inspect speaker polarity. On passive systems, red amplifier terminals should normally connect to red speaker terminals and black to black. Powered monitors can also have polarity switches or signal-processing options. Turn the system off before changing physical wiring.
Use frequency tones responsibly
The frequency slider covers a practical 80 Hz to 2 kHz range for quick speaker checks. Low frequencies interact strongly with room boundaries, while midrange tones are more useful for finding rattles, driver dropouts, and level differences. Sweep slowly and keep the level conservative. A loud sine wave concentrates energy and can stress a driver more than normal music.
This tool does not calibrate monitors or produce a measurement graph. For room correction you need a calibrated microphone and dedicated analysis software. Use this page for routing, placement, polarity awareness, and quick fault isolation, then move to the broader frequency generator if you need a specific test tone.