The Ghost in the Machine: Why Phase Comes Before EQ
We all experienced this. One adds low-end EQ to the kick drum channel, but nothing seems to happen when you stepp out pf the center FOH and moves little to the side. That majestic impact disappears in the room? This is not subjective. It is a phase problem.
Phase cancellation, not EQ
When two sources reproduce the same frequency but arrive at different times, their waveforms no longer add coherently. At certain offsets, they partially or fully cancel. No amount of equalisation can correct a timing error.
The acoustic crossover
In most sound systems, subwoofers and main loudspeakers overlap somewhere around 80–100 Hz. In this region, both systems reproduce the same content.
At 100 Hz, one full wavelength is 10 ms.
If the subwoofer arrives 5 ms late, it is 180° out of phase with the main.
At 80 Hz, the same delay is still a severe phase mismatch (≈144°).
Result: cancellation in the crossover region. Boosting EQ here does not restore energy; it increases drive into a null and often makes the result less consistent across the audience.
The correct fix
Fix the system in time before touching any EQ.
Using Smaart, measure the relative delay between subs and mains and apply the appropriate time offset. However, in classic L/R subwoofer arrangement you have often lost before you even started. Here more drastic measures are required. – like placing a centre bass for example … and other dirty tricks we cannot mention here.
When the phase traces overlap through the crossover region, low-frequency energy sums correctly and the kick drum regains impact—without any EQ boost.
Smaart is excellent on its own, but most users find they get much more out of it after some structured training. That’s where our seminars come in. At TZ Audio we run practical seminars, both online and in-venue. We offer seminar-only or full “all you need packages” including software & hardware. It’s simply the fastest way to become comfortable and confident with the measuring a sound system.
If you’re in Norway, Sweden, Denmark or Iceland – or elsewhere – we offer is online seminars and traveling to Norway is a valid option too of course. We’re here if you have any questions about the software or upcoming seminars.
Thanks for reading!