Why did the singer move to the left?

A stereo image is an auditory illusion created by two speakers and your listening position. It can move because the music was mixed that way, a channel is quieter, one speaker is closer, or the left and right room paths are different. The best troubleshooting sequence begins with checks that do not require moving furniture.

First, choose material that should be centred

Not every singer is mixed in the middle, and instruments may pan differently throughout a song. Use more than one familiar recording with a steady centred voice, or a mono test signal played through both speakers if your equipment supports it. Ask whether the lean persists across sources, tracks and listening volumes. If it occurs only on one song, you may be hearing the mix rather than your setup.

Make this a seated test at your normal ear position, not a comparison between walking around the room and sitting. A small shift left or right can alter direct-path level and timing; that is one reason a phantom centre can be sensitive to listener position.

Rule out a channel or balance issue

Confirm both speakers play, that the left and right cables or wireless channels are mapped as expected, and that balance, individual trims and DSP presets are unchanged. If your system has a channel-identification test, run it at a safe level. A muted or misrouted side can look like a room problem from the sofa, so solve these basic faults before pursuing reflection treatment.

Do not use a phone measurement to infer which cabinet is physically left or right without a controlled channel test. Room Tuner’s Pro left/right check in Full measurement specifically asks you to confirm the physical side heard; it does not “recognise” the speaker’s location from the microphone.

Make the two direct paths comparable

Measure from each speaker’s acoustic centre to the listening point. Aim for similar distance and ear-height alignment. Keep the speakers at similar height and, where feasible, similar distance from the wall behind them and the nearest side wall. Start with a symmetrical triangle rather than trying to compensate for one speaker’s poor location by turning up its volume.

Toe-in matters because it changes both on-axis direct sound and the distribution of side-wall reflections. Turn speakers by comparable angles first, then test modest adjustments in the same direction or symmetrically. Our toe-in guidecomplete speaker-placement guide

The room can make one side sound different

Genelec’s imaging guidance attributes left/right shifts at different frequencies to differences in direct and reflected paths, even in rooms that are geometrically symmetric when equipment placement is not. A desk, shelving, bare window or wall close to one side can alter the energy that reaches the seat. Avoid assuming the answer is “more absorption on the louder side”; first identify which surface or object is plausibly different and test a reversible change.

Move a portable obstacle, close a curtain, or shift the listening position slightly along the symmetry line. Listen to the centred reference again. An improvement is a clue, not proof; moving a source or listener changes many paths simultaneously. Avoid treating a blanket draped over one side as a permanent acoustic design without further checks.

What a measured left/right comparison can—and cannot—show

When a system lets you play the speakers separately, a controlled measurement can compare their level and relative midrange response at the same phone position. Room Tuner Pro’s left/right check is available within Full measurement when the paths can be clearly separated; the user confirms the physical channel heard. The app may withhold a conclusion if channel separation or evidence is weak. Its microphone cannot diagnose a damaged tweeter, a wiring defect or hearing asymmetry.

A phone response represents the speaker plus its room path at that seat. The result is relative, not a calibrated absolute SPL figure. Keep volume, playback route, phone position/orientation and microphone settings unchanged. For a broader discussion of those limits, read what an iPhone measurement can really tell you.

A practical one-change imaging test

1. 1 · Confirm the source

   Use a stable centred vocal or mono reference on more than one recording.

2. 2 · Confirm the channels

   Check routing, balance and trims. Save current settings before altering them.

3. 3 · Mark the geometry

   Measure left and right speaker-to-seat distances, heights and toe-in.

4. 4 · Match one variable

   Correct a distance or angle difference without changing the other variables.

5. 5 · Listen again

   At the same seat and volume, decide whether the image moved or stabilised.

6. 6 · Test reflections

   If needed, change one nearby object or curtain and repeat the same reference.

If a persistent lean survives basic channel, geometry and reflection checks, consult the system’s own diagnostics or a qualified technician; a room app alone cannot determine a hardware fault.