The Lucasfilm THX standards successfully established important criteria for the total performance of movie theatre sound systems throughout the USA and the rest of the world. Turning their attention to the domestic stage, Lucasfilm produced a similar set of standards for home audio systems. Home THX certification was a guarantee that these very high standards had been met and that high quality reproduction of multi-channel film sound was guaranteed.

 

The THX specification comprised identical Left, Centre and Right front speakers with a significant and carefully specified amount of vertical directivity to reduce floor and ceiling reflections and improve speech intelligibility; dipole surround speakers to match the effect of multiple monopole surrounds in a theatre; and a high performance subwoofer with a pre-determined 80Hz crossover to the satellites.

 

The KEF AV1 THX subwoofer used the established coupled cavity bass loading technique powered by an exclusive KEF activator amplifier supplying up to 200 watts to each of the two bass drivers. The amplifier featured partial current drive and a blend control to compensate for the phase difference due to the different positions of the subwoofer and satellite speakers.

 

The AV2 dipole surround provided all the performance required by the THX specification in a neat and compact package. When wall-mounted precisely to the left and right of the listening position, energy is radiated to the front and rear of the room with very little being radiated along the ‘null’ axis towards the listener. The result is that the listener is enveloped in ambient sound without hearing it as coming from the speakers themselves.

 

For the ultimate in home theatre sound, the three front speakers must be identical, ensuring that each on-screen sound remains absolutely consistent in quality despite its location, motion or change in perspective. The wide horizontal but narrow vertical dispersion of the AV3 allows accurate sound to reach each listener with the negative effects of ceiling and floor reflections greatly reduced.

 

Specification: Model AV1
System type: Active Subwoofer
Enclosure type: Coupled cavity
Dimensions (H x W x D): 428 x 550 x 500mm (16.8 x 22 x 19.7 inches)
Weight: 49.75kg (109.5 lbs)
Nominal impedance: active system
Amplifier requirements: active system
Frequency response: 35Hz to 80Hz +/-3.0dB, -6dB at 29Hz (THX); 22Hz to 150Hz, -6dB at 18Hz (Stereo)
Sensitivity: active system
Maximum output: 115dB
System: SP3169
Drive units: 2 x B250 bass unit (SP1215)
Amplifier: SP2201

 

Specification: Model AV2
System type: Three-way, wall-mount dipole surround
Enclosure type: Reflex
Dimensions (H x W x D): 260 x 310 x 130mm (10.2 x 12.2 x 5.1 inches)
Weight: 6kg (13.2 lbs)
Nominal impedance: 4 ohms
Amplifier requirements: 10-100W
Frequency response: 125Hz to 8kHz +/-3.0dB
Sensitivity: 89dB at 1m for 2.83V
Maximum output: 110dB
System: SP3163
Drive units: B110 bass unit (SP1083), 2 x 73mm (3inch) midrange unit (SP1342), 2 x 25mm (1 inch) tweeter (SP1231)
Crossover network: SP2218R (right system) and SP2218L (left system)
System: SP3232
Drive units: B110 bass unit (SP1083), 2 x 73mm (3inch) midrange unit (SP1342),  2 x 25mm (1 inch) tweeter (SP1231)
Crossover network: SP2245R (right system) and SP2245L (left system)

 

Specification: Model AV3
System type: Two-way, shelf/stand-mount
Enclosure type: Closed box
Dimensions (H x W x D): 570 x 240 x 190mm (22.4 x 9.4 x 7.5 inches)
Weight: 9.2kg (28 lbs)
Nominal impedance: 4 ohms
Amplifier requirements: 10-150W
Frequency response: 80Hz to 20kHz +/-3.0dB
Sensitivity: 90dB at 1m for 2.83V
Maximum output: 112dB
System: SP3177
Drive units: 2 x B160 bass unit (SP1340), 3 x NT25 tweeter (SP1353)
Crossover network: SP2219
System: SP3233
Drive units: 2 x B160 bass unit (SP1340), 3 x NT25 tweeter (SP1353)
Crossover network: SP2246

 

Download Reference Series Home Theatre Models AV1 AV2 AV3 Brochure
Download Reference Series Model AV1 Installation Instructions
Download Reference Series Model AV2 Installation Instructions
Download Reference Series Model AV3 Installation Instructions