Cloth mousepads are the quietest choice.
Cloth pads, no question.
The scratchy noise you’re hearing is hard mouse feet scraping against a hard surface. Plastic, glass, or aluminum pads amplify that. Cloth’s soft weave absorbs the friction instead of broadcasting it.
If you’re on a budget, any basic cloth pad from a reputable brand will do the job. Speed cloth (lower friction) is still quiet. Control cloth (higher friction) is quieter but not by much. The real enemy is anything glossy or rigid under your mouse.
One caveat: your mouse feet matter too. PTFE (white) feet are the quietest. Ceramic or glass feet will scratch on almost anything, even cloth, if there’s enough grit. Replace them if they’re worn.
Your mic will thank you for skipping the hard pad.
