With reference to sound quality space and visionSound quality we invented a “noiseless audio system”. The sound is delivered by ultra-low frequencies via its 10-cm deep speaker units thanks to a vibration-canceling woofer and a low-frequency-sound-enhancing passive radiator. The volume of the main body has been reduced to half of conventional models. This is the world’s smallest household audio system with an HDD. The compact disc slot gives a feeling of more space. The GUI is easy to. The stand-by power is 0.1 W or less. Fully lead-free solder and fully vinyl chloride-free materials are used throughout.