X-Over

X-Over turns your Mac into a serious 1×2 crossover for live sound and DJ systems.

Plug in your interface: route the low way to the subwoofer on the left output and the high way to the tops on the right. One stereo feed becomes a proper two-way system — without a hardware processor.

The low-level C engine measures its DSP execution time automatically inside the real-time audio callback and shows it on screen. This is the app's own processing time—not round-trip monitoring latency, which also depends on Core Audio buffers, the audio interface, transport, and conversion. Intentional alignment delay is shown separately.

What you get • Crossover point from 20 Hz to 20 kHz, drag in octaves
• Filter families: Butterworth 1–8, Linkwitz-Riley 2/4/8, Bessel 2–4
• Per way: gain, delay (ms, samples, or meters), polarity invert, mute, and metering
• Input: system audio or any physical channel
• 31-band ⅓-octave RTA for input, LOW, and HIGH
• Master limiter with a −0.1 dBFS ceiling so the digital output never clips
• Mono input by default — both ways share the same source, not left-to-sub by accident

Built as scientific software: Linkwitz-Riley sum is flat, slopes match theory, and when processing is off the signal passes through bit-exact. Change input or output only when offline; hardware inputs always ask for confirmation before going live to help avoid feedback loops.

From a simple DJ setup to a two-way PA — on the Mac you already own.