Efficiency bandwidth product (Fs/Qts); lower values favour sealed boxes, higher values suit ported designs.

Thiele-Small Alignment Calculator

Sealed and vented box volume suggestions from Fs, Qts, and Vas.

Fs (Hz)

Qts

Vas (litres)

Target Qtc (sealed)

How the Thiele-Small alignment calculator works

Driver Fs, Qts, Vas, and target sealed Qtc yield recommended sealed box volume and Fc. EBP (Fs/Qts) suggests whether sealed or ported alignments are typical starting points.

Key terms

Fs - free-air resonance of the driver.
Qts - total Q at Fs; lower values suit smaller sealed boxes.
Vas - volume of air with same compliance as the driver suspension.
EBP - efficiency bandwidth product; guides ported vs sealed choice.

Frequently asked questions

What is EBP? Efficiency bandwidth product (Fs/Qts); lower values favour sealed boxes, higher values suit ported designs.