Crossover Frequency
Definition
Crossover Frequency
The crossover frequency is the point where an audio system divides the signal between two or more drivers, with each driver handling frequencies above or below the crossover point. At the crossover frequency, both adjacent drivers contribute equally (-6 dB each for Linkwitz-Riley alignment). SonaVyx reveals crossover behavior through transfer function measurement, showing magnitude and phase alignment between drivers.
At crossover: each driver level = -6 dB (LR4) or -3 dB (Butterworth), combined = 0 dB
How It Is Measured
Crossover frequency and alignment are measured using transfer function analysis of the complete system. SonaVyx reveals the crossover region by showing magnitude response (looking for dips or peaks at the crossover point), phase response (checking for phase alignment between drivers), and coherence (verifying both drivers contribute coherently). Measuring each driver individually and then combined reveals the crossover behavior.
Practical Example
A two-way PA speaker has a crossover at 1.2 kHz. SonaVyx transfer function shows a 6 dB dip at 1.2 kHz with a rapid phase rotation. This indicates the woofer and tweeter are arriving out of phase at the crossover frequency. Adding 0.3 ms delay to the tweeter aligns the acoustic centers, and the dip disappears, producing a smooth transition through the crossover region.
Crossover Types
Linkwitz-Riley (LR) crossovers are the standard for professional sound. LR2 (12 dB/octave) and LR4 (24 dB/octave) provide flat magnitude through the crossover region when drivers are properly aligned. Butterworth crossovers produce a +3 dB peak at the crossover frequency when summed, which can be desirable or problematic depending on the application. Bessel crossovers prioritize linear phase (constant group delay) at the expense of slope steepness.
Phase at Crossover
The phase relationship between drivers at the crossover frequency determines whether they sum constructively or destructively. LR4 crossovers produce 360 degrees total phase shift at crossover (180 per filter), so both drivers arrive in phase. Odd-order crossovers (Butterworth 3rd order) produce 270 degrees total shift, requiring polarity reversal of one driver. SonaVyx phase display shows these relationships directly.
Acoustic vs Electronic Crossover
The electronic crossover frequency is where the filter divides the signal. The acoustic crossover depends on the physical driver response roll-off combined with the electronic filter. If a woofer naturally rolls off at -6 dB/octave above 2 kHz, an electronic crossover at 1.2 kHz produces steeper acoustic roll-off than the electronic filter slope alone. Measuring the complete system transfer function with SonaVyx reveals the actual acoustic crossover behavior.
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