Auxiliary Bass One AB1

Rogers, Catford (see also Rogers Birmingham)

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  • Year
  • 1985 ??
  • Category
  • Loudspeaker, headphone or earphone
  • Radiomuseum.org ID
  • 343169

Click on the schematic thumbnail to request the schematic as a free document.

 Technical Specifications

  • Main principle
  • Audio-Amplification
  • Wave bands
  • - without
  • Power type and voltage
  • No Power needed
  • Loudspeaker
  • Permanent Magnet Dynamic (PDyn) Loudspeaker (moving coil) / Ø 5 inch = 12.7 cm
  • Material
  • Wooden case
  • from Radiomuseum.org
  • Model: Auxiliary Bass One AB1 - Rogers, Catford see also
  • Shape
  • Miscellaneous shapes - described under notes.
  • Dimensions (WHD)
  • 162 x 570 x 190 mm / 6.4 x 22.4 x 7.5 inch
  • Notes

  • The Auxiliary Bass One is a sub-woofer system designed specifically for use with the LS3/5a in either the 15-ohm or the 12-ohm standard and bi-wire versions. The system addresses the limitations of the LS3/5a by increasing the low-frequency performance, increasing its sensitivity, and reducing the overall impedance, thus presenting a more manageable load for the amplifier. Each system is configured as a stand on a plinth, one required for each speaker. Thereby giving a true stereo subwoofer.

    Each enclosure houses one five-inch bass unit, the same type used in the LS3/5a (B110·SP1228). The unit is mounted horizontally within the cabinet and employs a symmetrically loaded technique to give an extended low-frequency performance. Although the high-frequency cut-off is set at 120Hz it is important that the sonic characteristics of the AB1 and LS3/5a bass units are the same to achieve a seamless Integration.
    The volume behind the driver is a closed box loading of the same displacement as the LS3/5a, whilst the volume in front of the unit is reflex loaded and sets the high-frequency cut-off point at 120Hz.

    Each AB1 should be positioned so that the reflex port fires inwards ie. towards each other.

    The decoupling spikes (provided) should be fined to the top of each AB1 cabinet.

    If you do not wish to damage the base of the LS3/5a with the spikes it is recommended that blu-tack™ be used as an alternative.

    Connection of the combined AB1/LS3/5a (see system setup) is into the subwoofer and through a high pass filter network, set at 120Hz. This effectively limits the low-frequency excursion of the LS3/5a reducing modulation effects on the critical mid-band and allows the unit to be used at higher levels. The reduced excursion also results in less energy being transmitted Into the AB1 cabinet, resulting in a cleaner more accurate bass response.

    The top set of terminals from the AB1 is connected (via link pins) to the LS3/5a.

    If the LS3/5a's have the bi-wire facility it is recommended that they be used in this mode. Note this system cannot be tr-wired!

    Recommended placement:

    12” (25cm) from the rear wall, and 20” from the side wall, speakers angled inwards so the axis cross just in front of the listener.

    Specifications:

    Type: Single driver subwoofer
    Frequency Response: 55 Hz to 120 Hz -3 dB
    Power Handling Combined System: 40 W unclipped program
    Recommended Amplifier: 25 to 100 W
    Crossover Frequency: 120 Hz
    Impedance: 8 Ω nominal
    Sensitivity: 82 dB @ 1m for 2.83 volts input
    Bass: KEF B110 (SP1228) 125mm cone
    Bass Loading: Symmetrically loaded – 24 dB/octave band-pass
    Cabinet: 15mm medite critically damped, satin black plinth
    Connectors: Rogers 4 mm binding posts with links
    Dimensions: 570 x 190 x 162mm
    Plinth: 24 x 240 x 210

     

  • Net weight (2.2 lb = 1 kg)
  • 8.2 kg / 18 lb 1 oz (18.062 lb)
  • Mentioned in
  • - - Manufacturers Literature
  • Author
  • Model page created by Gary Cowans. See "Data change" for further contributors.

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