Phone media volume must be at MAX. Then raise head-unit volume until the cone clearly moves. Sweeps below 40 Hz at high gain can damage tweeters or unported subs.
100%
Polarity Test
Plays a short positive pulse once per second. A correctly wired speaker's cone should push OUT toward you on each click. If it sucks inward, the speaker wires are reversed.
Tip: Turn head-unit volume up to ~50-70% for clear cone movement. Watch the cone directly, or place a small piece of paper on it — the paper should lift on each pulse.
Phase / Polarity (Listening)
Plays a correlated signal on L+R. Stand between the speakers and flip the R channel — in-phase images centered and solid, out-of-phase feels hollow, diffuse, or cancels bass.
200 Hz
Pink noise reveals polarity errors better than a sine — broadband cancellation is easier to hear. If flipping R makes it sound better, your R speaker is wired backwards. If flipping R makes it sound worse, L is the problem.
Frequency Sweep
Logarithmic sweep 20 Hz → 20 kHz. Listen for rattles, buzzes, dropouts, and frequency response issues.
20Hz
20 s
20 Hz
20 kHz
Full-range sweeps are loud on subs at the bottom end — keep volume conservative on the first pass.
Channel Identifier
Isolates the left or right channel with a distinct tone. Verify wiring — the correct speaker should be the only one playing.
—
Active Channel
Left channel plays 440 Hz; right plays 880 Hz. Alternating mode swaps every 1.5 s.
Crossover Tones
Preset frequencies for verifying crossover handoffs. Tap a tone — it should come out of the driver assigned to that band. Wrong driver = wrong crossover wiring or DSP.
—
Select Frequency
Hit the same button again to stop, or tap a different frequency to switch. Common XO points: sub/mid ~80 Hz, mid/tweeter 2.5–5 kHz.
SPL Meter
Uses the phone mic to measure sound pressure. Uncalibrated by default — for accurate readings, compare to a known SPL source once and tap "Calibrate".
--
dB SPL (approx)
406080100120
+30 dB
Hold phone at listening position. Phone mics compress above ~100 dB — treat readings above that as "very loud" rather than exact.
Reference Tracks
Curated audiophile/demo tracks by category. Tap any row to open on YouTube. For best sound, search these same tracks on Apple Music Lossless, Tidal HiFi, or Qobuz.