A frequency sweep plays tones from low (20Hz) to high (20kHz) across your speakers. It helps identify frequency response dips, rattles, or dead spots in your audio system.

Listen for: volume drops at certain frequencies (room acoustics), buzzing/rattling (loose parts), or complete silence (blown drivers). The sweep should sound smooth and continuous.

The stereo test checks left/right channel separation at a single frequency. The frequency sweep tests your speakers' performance across the entire audible spectrum — from deep bass to high treble.

Phone speakers typically can't reproduce frequencies below ~300Hz. Laptop speakers vary widely. Use external speakers or headphones for accurate full-range testing.