Crossover frequency calculator
The crossover is set by what your speakers can do, not by the subwoofer. Tell the calculator what's playing above the sub and it returns a starting frequency, plus the two settings people forget to check afterwards.
Frequently asked questions
What is a subwoofer crossover frequency?
It's the frequency where your main speakers hand over bass duty to the subwoofer. Below the crossover, the sub plays; above it, your speakers play. Setting it correctly is what makes a system sound like one seamless instrument instead of speakers plus a thumping box.
Why is 80 Hz the standard crossover recommendation?
80 Hz is low enough that the subwoofer can't be located by ear, and high enough that typical bookshelf speakers aren't strained. It's the THX reference point, and it's the right default unless your speakers are unusually small or genuinely full-range.
Where do I find my speaker's rated low end?
On the manufacturer's spec sheet, look for frequency response — e.g. '55 Hz – 20 kHz'. The first number is what this calculator wants. If two numbers are given (-3 dB and -6 dB), use the -3 dB figure.