Acoustic Enclosure: The most prominent feature is the sound-proof or sound-attenuating canopy that encases the engine and alternator. This enclosure is typically lined with sound-absorbing materials like foam, fiberglass, or rock wool to trap and muffle noise.
Insulated Engine Mounts: The engine is often mounted on rubber or other vibration-dampening materials to prevent the transfer of vibrations to the frame and enclosure, which can generate noise.