Audio reproduction systems are used to reproduce audio signals. 5, and a quotient of the total blade count divided by 110 is less than a difference \u22121) of the total pressure ratio minus one, and the total pressure ratio is greater than 4. The cargo container apparatus also includes a cargo container transporter having a base portion, an elevatable platform, a pair of side support rails, and front and rear ramps. The ratio value is compared to the adaptive threshold value for respective adjacent region pairs, to determine whether an edge is present between the respective adjacent region pairs. The bar-like parts are disposed at certain intervals therebetween in the longitudinal direction of the vehicle. It is determined if the number of requests for the alternative network location exceed a threshold value for a period of time, and if so, an alarm is generated.