1, 15 inch speakers are all 50 cm. Both centimeters and inches are units of length, and 1 inch equals 3.33 centimeters, so 15 inches equals 15 times 3.33 equals 50 centimeters. That is, the length of 15 inch is equal to 50 cm.

2. The installation method of speaker duct is "regular triangle method". A pair of speakers are arranged in a line facing the audience and placed on both sides of the display (or computer desk). The distance between the two speakers is 1 to 2 meters.