Speaker Box Calculator

Calculate optimal sealed and ported enclosure volume for a speaker driver based on Thiele-Small parameters.

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How It Works

Speaker enclosure design uses Thiele-Small parameters. For sealed boxes: Vb = Vas / ((Qtc/Qts)² - 1), where Qtc = 0.707 gives a maximally flat (Butterworth) response. Higher Qtc gives a bass bump but poorer transient response. Ported boxes are typically ~1.5× larger but extend bass lower. Key parameters: Vas = equivalent compliance volume, Qts = total Q factor, Fs = free-air resonance. Ideal drivers for sealed: Qts 0.3-0.5. For ported: Qts 0.2-0.4.