Controlled signal
The tool generates the test inside your browser with a bounded app-level gain. Your operating-system and hardware volume remain separate.
Online Frequency Sweep
A sweep helps reveal obvious dropouts, rattles and resonances. Listen at a moderate, fixed level and treat changes as clues rather than calibrated measurements.
20 Hz20,000 Hz
Perceived loudness will change with frequency even when digital level stays constant. Listen for repeatable jumps, dropouts or rattles rather than perfect loudness.
Local by default
Output tests do not upload audio. Microphone tools request permission only when started and explicitly state what stays in memory.
SCOPE / 01
What this test checks
A logarithmic sweep moves continuously between the selected start and end frequencies. It is useful for locating a repeatable transition, missing region or resonance before narrowing the range with a tone generator.
- A speaker or headphone changes abruptly across the audible range.
- You hear a rattle but do not yet know which frequency triggers it.
- The digital start, end and duration requested from the browser oscillator.
- Whether an abrupt change repeats at approximately the same point in both sweep directions.
- Whether a physical adjustment changes the same audible region.
- Flat loudness or calibrated frequency response.
- Whether a missing extreme is caused by the listener, device, fit or room.
PROCEDURE / 02
How to run this test
Keep the level moderate and change one thing at a time so the result remains useful.
- 01
Choose the start, end and duration.
- 02
Lower volume before sweeping toward an unfamiliar range.
- 03
Play once and note obvious jumps, rattles or missing regions.
- 04
Repeat in reverse after changing one fit, position or setting.
INTERPRETATION / 03
What your result means
Match what you heard or saw, change one variable, then use the linked check to verify the result.
| Observation | Likely cause | Next step | Retest |
|---|---|---|---|
| 01A sharp jump or rattle repeats at the same point. | A driver, enclosure, nearby object, headphone fit or room surface may have a narrow resonance. | Use the tone generator to bracket the smallest repeatable frequency range, then move or secure nearby objects. | Pinpoint the frequency |
| 02The sweep fades gradually near one extreme. | Normal device roll-off, room behavior, seal and personal audibility can all reduce perceived level toward the range limits. | Keep volume fixed and compare another device rather than raising extreme-frequency level sharply. | Understand frequency limits |
| 03Clicks or dropouts appear at different points each run. | CPU load, driver buffering, Bluetooth interference or another unstable part of the signal path is more likely than a fixed acoustic resonance. | Close high-load applications, compare wired output and repeat the same sweep duration. | Troubleshoot crackling |
| 04The sweep changes after reseating headphones or moving speakers. | Fit, listening position or room interaction was influencing the original result. | Use the position that produces the most stable repeatable result, then retest at the same level. | Check the output device |
VARIABLES / 04
Why results can vary
The generated signal stays controlled; the physical device, room and system path can still change what reaches you.
Human loudness sensitivity
Equal digital amplitude does not sound equally loud at every frequency, especially near the limits of audibility.
Sweep duration
A slower sweep makes narrow changes easier to locate, while a short sweep is better for a broad overview.
Hardware roll-off
Small drivers and their enclosures commonly become quieter before reaching the lowest or highest selected frequency.
Room and headphone seal
Position, reflections and leakage can create strong changes that are not present in the digital signal.
LIMITS / 05
Browser limits and safety
Online Frequency Sweep questions
Which direction should I sweep?
Either direction works. Repeating in reverse can help separate expectation from a repeatable change.
Why does volume seem to change?
Human sensitivity, device response, fit and the room all vary with frequency.
How long should the sweep be?
Ten to fifteen seconds is practical for an overview; longer sweeps make narrow changes easier to locate.