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Three 880 Hz beeps from the left speaker only. If you hear them on the right, your channels are swapped.

Three 1320 Hz beeps from the right speaker only. The higher pitch also helps confirm which side is which.

An 880 Hz tone in both channels, in phase. It should image as a tight phantom centre, midway between the speakers, with equal loudness on each side.

100 Hz in both channels, in phase. Bass should sound full and solid, locked to the centre.

The same 100 Hz with the right channel inverted. With correct wiring this should sound thin, hollow and diffuse, with much less bass than the in-phase tone. If it sounds fuller, one speaker is wired backwards.

A slow 8-second sweep through the woofer band. Listen for rattles, buzzes or cabinet resonances that only appear at certain frequencies. Keep the level modest.

Pink noise switching between speakers every second. Each side should sound identical in tone and level, and the image should snap cleanly between speakers with no centre leakage.

Noise panning smoothly from hard left to hard right over 6 seconds. The image should glide in a straight line at constant loudness, with no jump in the middle or dip at the ends.

Noise bursts stepping through 25, 50, 75 and 100% left and right. Each step should land at a distinct, stable position; blurred or wandering positions suggest imaging or room problems.

Mono noise stepping in fine increments from left through centre to right. The centre step should sit exactly between the speakers; if it pulls to one side, adjust toe-in or speaker position and try again.

Pink noise with the right channel inverted. Should sound extremely wide, diffuse and hard to locate, wrapping around the sides. A centred or narrow sound here suggests a channel or phase integrity problem.

Alternating 2-second blocks: identical noise in both channels (narrow, upfront) versus independent noise in each channel (wide, recessed). The contrast between the two is a rough gauge of how your system and room render front-to-back depth.

Noise shaped to the low-mid band. Most listeners localise this low in the stage, near floor level.

Noise shaped to the presence band. Tends to localise at tweeter height, straight ahead.

Noise shaped to the brilliance band. Often perceived above the speakers; compare with the low band for the full effect.

Short transient bursts at 2, 4, 6 and 8 per second. Attacks should stay separate and crisp as the tempo rises; smearing or blurring points at slow drivers, room splash, or an over-damped amplifier.

One isolated 20 ms transient. Should be a single clean crack with immediate silence after it; any echo, buzz or tail is coming from the room or the speakers, not the signal.

Warbling tones stepping through 1/3-octave bands from 20 to 200 Hz, 2 seconds each. Every band should speak at a similar level; a band that booms or vanishes is your room, not the cable.

A slow 20-300 Hz sweep with 2-second dwells at 40, 80 and 160 Hz. Frequencies that suddenly swell, sustain or rattle the room are your standing-wave hotspots.

Band-limited noise sweeping 50-400 Hz. With a well-integrated subwoofer the level should stay even all the way up; a dip near the crossover point means the phase or crossover setting needs work.

A 1 kHz tone alternating between channels while the right side drops in 0.5 dB steps. Note the round where you first hear the image pull left; that is roughly your balance sensitivity.

A 1 kHz tone stepping down in 6 dB increments to -30 dB. The step where it disappears into room noise marks your system's usable dynamic floor at that listening level.

Mono pink noise, identical in both ears. It should sit dead centre inside your head and stay there. A pull to one side indicates a channel imbalance in the headphones, cable or source.

A very quiet mono 1 kHz tone at -30 dBFS. Channel imbalance is easiest to hear at low level: listen for the image drifting off centre as you listen, and compare with your system's balance at normal level.

Two seconds of in-phase noise followed by two seconds with one side inverted, twice. The in-phase blocks should sound centred; the inverted blocks diffuse and hollow. If the inverted blocks sound more natural, one driver is wired out of phase.

Noise bursts with a tiny inter-ear delay, stepping 0, 0.15, 0.3, 0.45 and 0.6 ms. The image should walk from centre toward the leading ear. This is a simple interaural time difference approximation, not a real HRTF binaural render.

A slow 20-200 Hz sweep at a reduced, headphone-safe default level. Buzzes or rattles that appear only in one ear or one band point at a driver or fit problem. Keep the volume low.

A slow sweep through the sibilance region. Peaks that stab or hiss harshly show where a headphone is hot; a smooth, even rise and fall is the goal.

Tones at 60, 40, 30 and 20 Hz at equal level. An honest framing: below about 30 Hz many headphones roll off, and what you hear there is a mix of extension and distortion products, not a measurement.