Dynaquad

[1][2][3] The system originally had four speakers that were arranged in a diamond shape (centre-front, centre-left, centre-rear, centre-right).

[8] A simpler form of Dynaquad was adopted, allowing an easy adaptation of existing home setups.

[12] Electronic amateurs could build the circuit much more cheaply – e.g., with a four-position switch (four steps in level of the rear sound from min.

The system requires relatively flat impedance curves for the rear speakers to work properly, which was often the case in the tube-amplifier days.

He confirmed that he had developed a two channel virtual surround matrix that had only been partially realised by the record company on the Beach Boys releases.