Another effective method is a mass-loaded platform. A heavy slab of granite, marble, or dense MDF under a turntable or speaker reduces resonance because the extra mass is harder to set vibrating. Isolation racks with damping layers work on the same principle, keeping shelf equipment away from floor and footstep vibrations.
For speakers, decoupling stands and acoustic foam or rubber wedges help stop the cabinet from transferring energy into the floor. In studios, floating floors and isolation pads under monitor speakers are widely used for the same reason. Microphones often rely on shock mounts, which suspend the capsule inside an elastic frame so handling noise and footsteps never reach the recording.
