Why layout matters
A textbook crossover on a napkin still fails if inductors couple, grounds loop, or the network sits in a magnetic soup next to the woofer motor. Builders blame “the crossover design” when the real issue is parts placement and wiring.
Mistake 1: Parallel inductors / shared magnetic field
Big iron cores next to each other induce weirdness. Orient axes to minimize coupling; leave space; don’t stack coils like pancakes unless you know why.
Mistake 2: Long unshielded runs past the woofer magnet
Keep the network away from the motor when you can. Short, tidy leads beat artistic spaghetti.
Mistake 3: Star grounds ignored
Mix chassis, input, and network grounds casually and you invent hum. One clear reference; document it in the build notes.
Mistake 4: Padding the tweeter by ear only
L-pads and series resistors change response *and* impedance. Measure after, even roughly. “Sounds brighter in the garage” is not a transfer function.
Mistake 5: No damping on a ringing network board
A rattling PCB or loose coil is a mechanical oscillator. Secure parts; damp panels near the network.