Webcam, Mic & Speaker Test — What the Numbers Actually Mean

Run the Webcam, Mic & Speaker Test first, then use this guide to understand each reading and fix the most common problems before assuming your hardware is broken.

📷 Webcam Readings

Resolution & Live FPS

Resolution and frame rate come from the actual settings your camera and driver negotiated with the browser via track.getSettings(), combined with a live frame-timestamp counter for real FPS — not the number printed on the box.

Light Level & Sharpness

These are relative indicators computed from the visible frame — average brightness for light level, and edge-contrast for sharpness. They flag "too dark" or "clearly out of focus," not a calibrated camera-quality score.

🎤 Microphone Readings

Browsers can't report a calibrated decibel (SPL) value — that depends on microphone sensitivity and OS gain, details the Web Audio API doesn't expose. Treat the level meter as relative loudness, useful for spotting silence, inconsistency, and clipping, not for comparing absolute loudness across different microphones.

Electrical Hum (50Hz/60Hz)

This checks for elevated energy specifically at mains frequency (50Hz or 60Hz depending on your region) and its harmonics — a strong signature of ground loops, unshielded USB cables, or a mic sitting too close to a power adapter or laptop charger. It's distinct from general room noise, which spreads across many frequencies rather than concentrating at one.

AGC / Noise Pumping

Many OS drivers and cheap mics apply Automatic Gain Control (AGC), which boosts the mic's gain during quiet moments and reduces it during loud ones. The tell-tale sign is the background noise floor visibly rising right after you stop talking, then settling back down over a second or two — sometimes called "noise pumping" or "breathing." This test watches for exactly that pattern over a ~20 second rolling window.

Plosives / Pops

P, B, and T sounds create a sharp, fast burst of low-frequency (bass) energy when spoken directly into a mic — the classic "pop" or "thump" you hear on badly-mic'd audio. This counts how many of those bursts happened during your test.

🎯 Video Call Readiness Score

This combines your camera and microphone readings (plus whether you've run a speaker test) into a single 0-100 score with a checklist, so you can see at a glance whether you're ready for a call instead of interpreting a dozen separate numbers yourself.

Speaker output can't be auto-graded — there's no way for a webpage to confirm you actually heard sound — so it's scored as tested/not-tested rather than pass/fail. Play any speaker test button at least once to mark it complete.

📈 Speaker Frequency Response (Mic Loopback)

This plays a slow sweep from 60Hz to 8000Hz through your speakers while listening back through your microphone, then plots the result — dips or peaks can point to weak bass response, a rattling frequency, or a struggling driver.

🌀 Distortion Estimate (THD)

Plays a steady test tone through your speakers and measures how much extra energy shows up at harmonic frequencies (2×, 3×, 4×, 5× the original tone) compared to the tone itself — more harmonic energy means more distortion. You can choose Bass (100Hz), Mid (1000Hz, the standard reference), or Treble (6000Hz) depending on what part of your speaker's range you want to test.

Like the frequency response test, this is a loopback estimate — your microphone's own harmonic response is baked into the number, so treat it as useful for comparing volume levels or speaker positions on your own setup, not for comparing against a manufacturer's published spec.

⏱ Webcam Capture Latency

Point your camera at the flashing box in the webcam section, and this measures the real time from when the box turns white on your screen to when your camera actually captures that change — a genuine end-to-end pipeline latency, not a number from a spec sheet.

🎯 Focus/Exposure Stability

Watches your camera's light and sharpness readings over about 8 seconds while you sit still. A healthy camera settles quickly and holds steady; a camera that's continuously "hunting" — re-focusing or re-exposing even on a static scene — shows those values constantly swinging instead of settling.

📈 Trend History

Every time you finish a camera, mic, or distortion test, a snapshot is saved to a rolling history (last 10 sessions) stored only in your browser — never uploaded anywhere. Useful for spotting things like "did my mic's noise floor get worse after I changed USB hubs" over multiple sessions.

🔊 Speaker Readings

The Left/Right/Both/Sweep tones are real hard-panned oscillator signals — what you hear is exactly what's being sent to that channel. If audio plays from the wrong side, that's a genuine channel-routing issue (wiring or an OS balance setting), not a bug in the test. The frequency sweep (60Hz–8000Hz) helps you catch rattling or buzzing at specific frequencies, which often points to a loose speaker driver or enclosure.

Common Problems & Fixes

• Camera shows black preview: Check OS-level camera privacy permissions before assuming hardware failure.
• Mic shows no signal at all: Confirm the correct input device is selected in the dropdown, and that it's not muted at the OS level.
• Speaker test is silent: Check your OS default output device and volume — this is far more often the cause than a hardware fault.
• Echo during calls: Enable Echo Cancellation (shown in the mic stats) or use headphones instead of open speakers.

Frequently Asked Questions