Type I Noise Reduction 911

dbx Inc.; Waltham (MA)

  • Year
  • 1990 ??
  • Category
  • Miscellaneous (Other, Various) - see notes
  • Radiomuseum.org ID
  • 290662

 Technical Specifications

  • Main principle
  • Audio-Amplification
  • Wave bands
  • - without
  • Power type and voltage
  • Powered by external power supply or a main unit.
  • Loudspeaker
  • - For headphones or amp.
  • Material
  • Various materials
  • from Radiomuseum.org
  • Model: Type I Noise Reduction 911 - dbx Inc.; Waltham MA
  • Shape
  • Rack
  • Dimensions (WHD)
  • 38 x 133 x 262 mm / 1.5 x 5.2 x 10.3 inch
  • Notes
  • The 911 incorporates one channel of encode and one channel of decode circuitry in the dbx® Type I format. The Type I system doubles (up to a maximum of 115 dB) the dynamic range of the storage or transmission medium. This is achieved through compressing the signal by a 2:1 ratio during record then expanding the signal 1:2 with a precisely complementary deemphasis during playback. The companding is linear over a 100 dB range. It requires no pilot tones or special calibration. 

    Type I provides best results when used with transmission or storage media exhibiting flat frequency response (±1 dB 20 Hz - 20 kHz) - typically open reel recorders running at 15 or 30 ips, or digital media. The signal's dynamic range is cut in half, with the hottest levels considerably reduced and the softest passages boosted. On decoding, the signal is precisely expanded back, and the original dynamic range of the program is retrieved without hiss, saturation distortion, or degradation of frequency response. 

    Industry standard Type I noise reduction.
    Greater than 40dB improvement in dynamic range for typical systems.
    Front panel adjustable to match facility levels from -12 to +16dBu.
    Hardwire bypass switch.

    Used in a DBX 900 rack adapter. The rack adapter can hold up to 9 modules, and provides DC power to each module.

  • Net weight (2.2 lb = 1 kg)
  • 0.3 kg / 0 lb 10.6 oz (0.661 lb)
  • Author
  • Model page created by Bartosz Szwed. See "Data change" for further contributors.

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The model Type I Noise Reduction is part of the collections of the following members.