Mixing on a single small speaker reveals balance problems that stereo nearfields hide

Single-speaker mono listening (historically via the Auratone 5C Super Sound Cube) provides advantages that stereo nearfields cannot: (1) no phantom-image instability — every sound’s position is unequivocally the physical speaker, so level balances can be judged with accuracy; (2) the small single-cone design has no crossover electronics and therefore no crossover-region comb filtering; (3) low output means room modes have minimal impact; (4) summing stereo to mono raises central sounds by approximately 3dB relative to edge sounds, exposing mix balance shifts. Bruce Swedien claimed approximately 80 percent of Michael Jackson’s Thriller mix was done on Auratones. Modern substitutes include the Avantone Mix Cube.

Examples

A central lead vocal that appears balanced in stereo will be 3dB louder in mono compared with sounds at the stereo extremes — if the mix collapses in mono, that vocal may now overwhelm everything else.

Assessment

Explain why a mix engineer might discover that a lead synth hook that sounded fine in stereo becomes problematic in mono. What specific property of the Auratone made it useful for judging bass-instrument balance?