Stereo speakers

Test left, right, center and polarity: L, R, both in phase, one side inverted

Stereo system sounds thin, wide or off-center? Four test sounds at a calibrated level tell you if the left and right speakers are swapped, if the balance is off, and if one speaker is wired + / - backwards.

Works with

SPEAKERS · HEADPHONES · TV · CAR

Type

Test

Video

Watch on YouTube · 0:42

Field card

No. 029 · A4 PDF

The video

Watch on YouTube0:42Published 2026-10-02

Before you start

• Volume low, then raise it
• Sit centered, speakers about 60° apart
• Phone: Mono Audio OFF, Balance centered
• Receiver: plain Stereo mode

Steps

1. LEFT only

   Pass: only the left speaker plays

   If not: From the right? Speaker wires or source cables crossed

2. RIGHT only

   Pass: only the right speaker plays

   If not: From the left? Speaker wires or source cables crossed

3. BOTH · in phase

   Pass: one sound, in the middle, full

   If not: Pulled to one side? Balance to center

4. BOTH · one side inverted

   What a swapped + / − wire sounds like

   Pass: Wired right: wide, thin, less bass, no center

   If not: Almost silent? Your playback is mono

How you know it worked

• Step 3 centered and full, step 4 wide and thin = wired right

If it didn't work

• Step 3 sounds like step 4? Amp off, swap + and − at ONE speaker
• Play it again at the same volume

Full sequence

L · R · BOTH = CENTER · INVERTED = WIDE + THIN

Notes from the card

• 3 sounds like 4? Amp off, swap + / − at ONE speaker
• 4 almost silent? Your playback is mono
• L or R from the wrong side? Wires or source cables crossed
• Off center? Balance to center

Sources

Snap One MoIP Amp install guide, "Verifying speaker phase"; Yamaha RX-V485 owner's manual, YPAO warning messages; Genelec, "Monitor placement"; Apple Support, "Adjust audio settings on iPhone"; YouTube Help, "Recommended upload encoding settings".