Certified to THX ULTRA2 and THX SELECT2 standards, the formidable Ci200QSb-THX in-wall subwoofer delivers deep bass and theatre thumping output capabilities, matched to the uncanny ability to deliver all the drama and emotional intensity of full theatre sound quality.


With a powerful high-output 200mm (8in.) sub-bass driver, the Ci200QSb-THX can be used in passive mode to supplement the LF output of KEF’s Ci series in-wall or in-ceiling speakers. In Active mode, when 2 pair of the Ci200QSb-THX subwoofer are powered by the powerful 250Wx 2 KEF KASA500 System Amplifier the performance meets THX Select2 specification. When 4 pair of the Ci200QSb-THX are powered by 2 KEF KASA500 System Amplifiers the performance meets THX Ultra2 specification.


  • Nominal Impedance:

    6 Ohm - Passive Mode (Crossover "ON")
    N/A - Active Mode (KASA500)

    Sensitivity (2.83V/ 1m):

    85dB - Passive Mode (Crossover "ON")
    N/A - Active Mode (KASA500)

    Frequency Response:

    40Hz-100Hz - Passive Mode (Crossover "ON")
    18Hz-140Hz - Active Mode (KASA500)

    Crossover frequency:

    100Hz - Passive Mode (Crossover "ON")
    N/A - Active Mode (KASA500)

    Recommended Amplifier Power:

    10-150W - Passive Mode (Crossover "ON")
    KASA500 - Active Mode (KASA500)

    Drive Units:

    LF: 200mm (8 in.)

    Product external dimensions:

    Diamater: 273 mm (10.75 in.)
    Depth: 106mm (4.17 in.)

    Cut-out dimension:

    H x W: 238mm (9.37 in.)

    Mounting depth from surface:

    Product only: 101.6mm (4 in.)

    Optional rough in frame: