3Com CP-1 owner manual Stereo Logic

Theory and Design

Lexicon

result is superior steering. An added benefit is that the CP-1 is the only Pro Logic decoder which needs no front panel input balance control; the user need not bother with this adjustment. You can check the quality of the balance and azimuth in a tape or disc if you wish by turning the Auto Azimuth/Balance parameter off and observing any changes in the location of dialog and effects.

In addition, because the side and rear cancellation of dialog is unusually good even with poor material, you can use Stereo Logic to set the rear channel filtering higher than is recommended in the Pro Logic specifica- tions. This added surround brilliance makes some effects, such as falling rain all around you or objects zooming from rear to front, much more convincing. This feature should be used with caution, however, since in this mode the decoder is different from the one on which the film was mixed.

Stereo Logic

The Stereo Logic program is primarily designed for the playback of music through film-sound systems. Its basic structure is similar to Pro Logic but it contains more variable parameters. In the Preset version of Stereo Logic these parameters are set for music but they can be changed to produce a versatile program for film sound as well.

The range of the Rear Delay parameter is 0-32 ms, as opposed to 16-32 ms in Pro Logic, for use with music programs in which you may want to hear the front and rear outputs of the program simultaneously.

Music does not necessarily contain a crucial, centrally located element analogous to the dialog in films. So the Preset version of Stereo Logic has no automatic adjustment for interchannel time delay and balance (that is, the Auto Azimuth/Balance parameter is off). The Front Effect parameter, which controls the steering among the front three channels, is preset half way up, meaning that centrally located sounds are diminished by 6 dB in the side speakers and vice-versa. The setting for Dolby Stereo films is 16 (up all the way).

The Rear Effect parameter controls the steering of effects, music and ambient sounds to the rear speakers. Its preset value is determined by the speaker configuration specified by the user. (See page 13.) The preset value is zero if there are no rear speakers in your system and 8 (of a possible 16) when there are rear speakers. When the Rear Effect is set to zero all rear

Page 48