The consultant arrived at 9 AM and began tuning. By 4 PM, he had applied forty-one parametric EQ filters, adjusted seven delay lines, changed two crossover frequencies, and reversed the polarity on the right subwoofer. He announced that the system was 'dramatically improved' and packed up to leave.

I had taken a transfer function measurement at 8:55 AM, before he started. I took another at 4:05 PM, after he finished. The before/after comparison was, as they say in academia, not supportive of the consultant's hypothesis.

The 'before' measurement showed ±4 dB deviation from 60 Hz to 16 kHz, coherence above 0.8, and a smooth phase response. Not perfect, but respectable. The 'after' measurement showed ±11 dB deviation, coherence dropping to 0.3 in the crossover region, and phase discontinuities at three frequencies where filters were fighting each other.

The frequency response was 7 dB worse by every objective metric. The coherence was destroyed at the crossover. The phase response had more discontinuities than a roller coaster. Seven hours of expert tuning had taken a decent system and made it substantially, measurably, provably worse.

The consultant disputed the measurements. He said the system 'felt' better. When shown the overlay, he said the measurements 'didn't capture the whole picture.' The measurements captured the whole picture. The picture was not flattering.

The Moral: Always take a baseline measurement before touching anything. SonaVyx's before/after comparison provides objective proof of whether your adjustments helped or hurt — because intuition is not a measurement, and 'it feels better' is not a specification.