The Surround Direction and Base Width Controller Dimensions is a unique 5.1 mastering device that allows the modification of the spatial components of surround program. The device is based on the M/S stereo technology that has been expanded to be used with 5.1 surround sound system Additional, fully parametric EQ bands in the M/s chain enhance to possible modifications while the elliptic equalizers maintain stereo and mono compatibility

Surround Direction and Base Width Controller

DIMENSIONS is a unique mastering tool for 5.1 format surround sound. It is an analog processor designed to regulate the base width and depth of 5.1 format audio so as to increase the apparent width and depth of the mix. With the DIMENSIONS, and M/S based processing is now available for the 5.1 format.

Surround Direction Control Unit

There are separate sections for the control of the Width and the Depth of the program. In addition the Elliptic EQ section allows the modification of the low frequency crosstalk between left and right and front and surround independently. A Matrix section makes it possible to convert a 4 channel surround input signal into 5.1 format.

The unit converts the surround input signal into two M/S signals. The first signal describes the left to right relationship; the second signal describes the front to fear relationship. The operation of this processor has no effect on the LFE channel, and it is not integrated into the regulation, its signal bypasses all the processing elements. However, depending on the operation of the unit, the output matrix can affect the behavior of the LFE channel. In addition, there are three switches, which allow additional manipulation of the signals at the input. FRONT-REVERSE and SRD-REVERSE switches the left channel with the right channel, and the left surround channel with the right surround channel respectively. The DEPTH REVERSE switch switches the left and right front channels with the respective surround channels without affecting the center channel.

The Base and Direction Control
With the WIDTH BASE and DEPTH BASE pots, the width and depth of the program can be independently changed. The regulation values are indicated as a percentage of the original base width and there is an adjustment range of 0% to 200%. With the setting 100% the signal remains unchanged. If the WIDTH BASE pot is turned to the left (the 0% direction), the width is reduced. When placed in the 0% position, the sound field narrows to a single point source. Settings above 100% produce an extended base width, and the sound source can appear to be located beyond the borders of the loudspeakers. The DEPTH BASE operates in the same way as the WIDTH BASE except that it regulates the relationship between the front and the surround channels, (the depth of the sound field).

The WIDTH DIRECTION and DEPTH DIRECTION pots regulate the width and depth of the program (independently of each other). In the C position, there is no change in the program. If the WIDTH DIRECTION pot is turned to the left, the sound source shifts to the left and visa versa. In the extreme left position, the right channel signal is completely shifted to the left channel. Unlike a balance or pan-pot control, (that mutes one side of a signal when it is turned completely to the opposite side), this signal is not just simply muted, but is summed with the signal on the left channel.

The DEPTH DIRECTION operates like the WIDTH-DIRECTION (except that it affects the depth of the program). In this case the signal is moved forwards (position F) to the front monitors, or backwards (position S) to the surround monitors.

The SURROUND-BASE and SURROUND-DIR operate like a normal stereo direction mixer, but only for the surround channels. This process is a part of the spatial direction mixer, and is used to adapt the width and the direction of the surround channels to the front channels, and both pots operate as described above. The BASE pot allows the user to change the width of the signal from 0% (mono) up to 200% of extended base width. The direction pot is used to adjust the surround signal from normal (SC) to mono on the left channel (SL), or to mono on the right channel (SR). This pot is also used for the adaptation of an artificially produced stereo signal from a 4-channel input signal.