Pieces on the physics you run into when tuning a system — and on what software can and cannot do about it.
Feedback is not bad luck, it is a loop with gain. Which lever buys how many decibels — ordered by effect, not by effort.
The corner gives you level and takes away evenness. Two subs left and right lay a striped pattern across the audience. Changing either costs nothing.
A deep, narrow notch in the response cannot be equalised away. Why that is, how to recognise it, and what actually helps instead.
The crossover region sounds thin, the kick has no punch. Why measuring distances is not enough, what counts instead, and how to verify the result.
A microphone with a known deviation beats a flat one without. What a measurement mic has to do, what you can skip, and what happens without calibration.
80 Hz is a home-cinema convention, not a PA rule. What really sets the crossover, why crossing higher demands tighter time alignment, and how to verify your choice.