Why split the signal

Why it matters

The crossover is where a multi-driver build succeeds or fails. Understanding why you split the signal at all makes every later decision — slope, point, phase — easier to reason about.

How it works

A large woofer moves a lot of air for bass but is too heavy and too big to reproduce treble cleanly; the cone breaks up and beams. A small tweeter handles treble but can’t displace enough air for bass without tearing itself apart.

So you give each driver only the band it does well:

• The woofer gets a low-pass filter — it keeps the lows and rolls off the highs.
• The tweeter gets a high-pass filter — it keeps the highs and rolls off the lows.

The frequency where they hand over is the crossover point. Around it both drivers play, so their outputs must add up smoothly in both level and timing. That overlap region is where phase matters — get it wrong and they cancel instead of sum.

This filtering can happen two ways: passive, after the amplifier with coils and capacitors, or active/DSP, before the amplifier with a separate amp channel per driver.

Common mistakes

Simple example

Related concepts

• Crossover
• Driver types
• Phase