Everyone at the Riverside Festival agreed the sound was clear, loud, and punchy. Everyone also agreed that something felt wrong. The kick drum didn't thump — it sloshed. The bass guitar didn't groove — it dragged. It was like listening to music through a time smear.

The system designer had flown the main PA on towers 3 meters in front of the sub stacks. To align the two, he'd measured the distance difference and applied delay to the mains so they'd arrive at the mix position simultaneously with the subs. Good practice — except he'd made a unit conversion error and applied 15 milliseconds too much delay to the subs instead of the mains.

The subs were now arriving 15 ms late relative to the mains. At 67 Hz, 15 ms is exactly one full wavelength — so that frequency was actually reinforced. But at the crossover region around 100 Hz, the misalignment caused a broad cancellation notch and a perceived timing smear. Every bass note felt like it was chasing the beat and arriving just late enough to be noticeable but not late enough to be obviously broken.

Sub-main alignment is critical. The ear is remarkably sensitive to timing at low frequencies because bass transients (kick drums, bass plucks) define the rhythmic feel of music.

The Moral: Bass timing is everything. SonaVyx Transfer Function shows both magnitude and phase — verify sub-main alignment by checking the impulse response and group delay, not just frequency response.