Pros

Big, punchy bass for very little money
Four switches per earpiece change the bass and treble (16 sound settings)
In the default setting the bass mostly stays out of the vocals' way

Cons

With the bass switches up, bass can spill into the mids and muddy voices
The switches need the included pin tool; fingernails won't do
Clear plastic shells and cable can yellow over time
No carry case, and the sound feels fairly closed-in

Updated 27 October 2026

The KZ Castor Bass is the bass-heavy version of KZ’s Castor earphones, and it costs very little. Each earpiece has four small switches that change the bass and treble, giving 16 sound settings. You flip them with the included pin tool, not your fingernails.

In the default setting the bass is big but mostly stays out of the way of vocals. Turn the bass switches up and it can spill into the mids and make voices sound muddy; some reviewers prefer the regular (non-Bass) Castor for that reason. The sound feels fairly closed-in rather than spacious, there’s no carry case, and the clear plastic shells and cable can yellow over time.

Two dynamic drivers per side (10 mm for bass, 8 mm for mids and highs)
Four tuning switches per earpiece, 16 sound settings
Detachable cable with a 0.75 mm 2-pin connector, 3.5 mm plug
Clear resin shells