• The Optimus 745 speaker system is sold by Radio Shack.speaker image by Byron Moore from Fotolia.com
  
  The Optimus 745 stereo rack system has a 100-watt-per-channel amplifier. Equipped with a CD changer, this system looks good in a simulated black wood grain veneer cabinet. The cabinet design enhances the bass from the sound system, and the CD changer can handle up to 24 CDs at one time.
  
  

General Specifications

• The system needs 120 volts of AC current, delivered at 60 hertz (Hz). It will use 230 watts of electricity while the system is in use. The system measures at 16 1/2 by 16 1/2 by 18 1/8 inches and weighs in at 36 pounds. This system is equipped with a 24-disc bi-directional radial changer that will only accept 5-inch CDs. The optical source for this system is a 3-beam semiconductor laser. It has a signal to noise ratio of 73 decibels. You can control this system with its included infrared control that requires two AA batteries.
  
  

Amplifier and Tuner Specifications

• The system has three different amplifiers: a main, a center, and a surround amplifier. Each has bass, E-bass and treble control of +/- 10 decibels. The system has a nominal output impedance of 8 ohms for its speaker outputs and 8 to 32 ohms for its headphones jack. The system has a FM tuner frequency range of 87.9 to 107.9 MHz in 200 kHz steps and 87.5 to 108 in 50 MHz steps. Its AM tuner frequency range is 520 to 1710 kHz in 10 kHz steps and 522 to 1710 kHz in 9 kHz steps.
  
  

Speaker Specifications

• The Optimus 745 system has three speakers: a main, center and surround. The main speaker measures at 36 by 12 by 11 1/2 inches and weighs 26 pounds. Its enclosure has a removable grill and has a 10-inch woofer, 4-inch midrange and a 3-inch tweeter. It has a frequency response of 40 Hz to 20 kHz, with a sensitivity of 90 decibels, and a maximum power of 200 watts. The center speaker measures at 11 by 4.56 by 5 1/2 inches and weighs 2.14 pounds. It is a 4-inch full-range speaker in a fixed-grill enclosure. It has a frequency response of 160 Hz to 16 kHz with a sensitivity of 88 decibels and a maximum power of 30 watts. The surround speaker measures at 7.12 by 4.56 by 4.56 inches and weighs 2.3 pounds. It is a 4-inch full-range speaker in a fixed-grill enclosure. It has a frequency response of 160 Hz to 16 kHz with a sensitivity of 88 decibels and a maximum power of 30 watts.