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The MTC-81BB8 is designed for use in applications requiring preinstalled backcans and is compatible with ceiling speakers having a 286 mm (11.25 in) mounting circle diameter, such as the JBL 8138 ceiling loudspeaker, and the JBL MTC-81TB8 tile bridge for suspended ceilings.


  • Fits 8138 speaker and MTC-81TB8 Tile Bridge
  • Extra-large 7.4 liter (0.26 cu ft) volume allows for extra bass
  • Industry standard 286 mm (11.25 in) mounting circle
  • Five conduit knockouts
  • Nesting during storage minimizes storage space requirements

JBL MTC-81BB8 Pre-Install backcan for 8138, 7.4 liter, 7"H x 11-3/4" dia

  • Internal Volume

    7.4 liters (0.26 cu ft)


    22 mm (0.87 in) diameter opening

    Five (5) locations

    4 on side of can
    1 on top of panel of can

    Suspension Tabs

    2 flexible perforated mounting straps, one on each side.

    Attachment Points

    4 clip-nuts on 286 mm (11.25 in) mounting circle fix M4 tapping screws for attaching tile bridge to backcan, plus 4 thru holes providing clearance for screws from speaker to attach to tile bridge (see assembly drawing).


    16 gauge (1.3 mm thick) steel, finished in black polymer E-coating for a high level of rust resistance.

    Dimensions (H x W x D)

    178 mm (7 in) height x 300 mm (11.75 in) width and depth

    Net Weight (ea)

    1.1 kg (2.5 lbs)

    Shipping Weight (ea)

    1.5 kg (3.2 lbs)

    Associated Models

    8138 200 mm (8 in) ceiling speaker
    MTC-81TB8 tile bridge for 600 mm (24 in) ceiling tile applications.

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