LONG-A

Speaker + subwoofer test · stereo pair, polarity, 20–200 Hz sweep and a held tone every 10 Hz

Type

Setup

Video

Watch on YouTube · 8:56

Field card

No. 033 · A4 PDF

The video

Watch on YouTube8:56Published 2026-10-10

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

5. IN PHASE vs INVERTED

   Back and forth: listen for the change

   Pass: Wired right: in phase centered, inverted wide

   If not: In phase wide and thin? Amp off, swap + / − at ONE speaker

6. SET LEVEL on this tone

   Comfortable, not loud. Then don't touch it

   Pass: Never turn up for the lowest notes

   If not: Buzzing already? Turn down

7. SWEEP 20 → 200 Hz

   Something buzzes? Note the Hz

   Pass: Booms and dips = the room, not a fault

   If not: Rattle heard? Jump to that Hz chapter

8. WALK THE ROOM

   Press a hand on what you suspect

   Pass: Buzz stops under your hand = found it

   If not: Silent? That note is below your sub's range

If it didn't work

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Full sequence

L · R · BOTH · INVERTED · A/B · LEVEL · SWEEP · 20 … 200 Hz