Dynaquad, or DY, was a

matrix decoder Matrix decoding is an audio technology where a small number of discrete audio channels (e.g., 2) are decoded into a larger number of channels on play back (e.g., 5). The channels are generally, but not always, arranged for transmission or recordin ...

4-channel

quadraphonic sound Quadraphonic (or quadrophonic and sometimes quadrasonic) sound – equivalent to what is now called 4.0 surround sound – uses four audio channels in which speakers are positioned at the four corners of a listening space. The system allows for th ...

system developed by

Dynaco Founded by David Hafler and Ed Laurent in Philadelphia, Pennsylvania in 1955, Dynaco was an American hi-fi audio system manufacturer popular in the 1960s and 1970s for its wide range of affordable, yet high quality audio components..Dunn, Greg, ...

in 1969. The system originally had four speakers that were arranged in a diamond shape (centre-front, centre-left, centre-rear, centre-right). Initially (first available in 1969 with th ''Dynaco SCA-80Q'' amplifier ), it was introduced as a derived (2:2:4) four channel "decoding" system based on the

Hafler circuit The Hafler circuit is a passive electronics circuit with the aim of getting derived surround sound or ambiophony from regular stereo recordings without using costly electronics. Such circuits are generally known as matrix decoders. The Dynaquad ...

, where the back channels played ambient sounds recovered from standard stereo sounds. As such it wasn't used initially used as an encoding method (a similar approach was used on the

Electrovoice Electro-Voice (EV) is an American manufacturer of audio equipment, including microphones, amplifiers, and loudspeakers, focused on pro audio applications such as sound reinforcement. As a subdivision of Bosch Communications Systems Inc. since 20 ...

Stereo-4 Stereo-4, also known as EV (from Electro-Voice) or EV-4, was a matrix 4-channel quadraphonic sound system developed in 1970 by Leonard Feldman and Jon Fixler. The system was heavily promoted by RadioShack stores in the United States, and some rec ...

system).

Commercial usage

4 0 channels (quadrophonic)(quadrophonie) label

A simpler form of Dynaquad was adopted, allowing an easy adaptation of existing home setups. The two forward speakers remain in their normal positions, with the user only needing to add two similarly positioned back speakers, forming a square (front-left, front-right, back-left, back-right). Four channel record pioneers

Vanguard Records Vanguard Recording Society is an American record label set up in 1950 by brothers Maynard and Seymour Solomon in New York City. It was a primarily classical label at its peak in the 1950s and 1960s, but also has a catalogue of recordings by a n ...

started to use it as an encoding/decoding matrix (4:2:4 format) in 1971. There were few albums released in the format. The competing

system was very similar and can be considered as compatible, as both use very similar decoding matrixes (based on the

). The left and right rear speakers are connected to the two-channel stereo amplifier via a passive matrix circuit, while the front ones stay directly connected to the amplifier. A lot of stereo material, recorded with a central, non-directional microphone (kidney pattern) placed in front of the orchestra, possessed suitable phase difference stereo signals. When taken from this passive speaker matrix for the rear channels, they produced a quasi-quadraphonic effect at low cost (the patent specifies the use of one fixed 10 ohm resistor and three variable 20 ohm resistors in a star arrangement). Especially for classical music, a fine impression of concert-hall ambiance is achieved with such a system. Dynaco sold this matrix circuit (''Dynaco QD-1 Quadaptor'', introduced in 1971)with a large and triple high-wattage potentiometer inside. 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. to max. level) using fixed resistors of, for example, 20, 10, 5 and 0 (short-circuit) ohms. Because, in practice, only the highest level was of any use, a more basic set-up with only the fixed 10 ohm resistor at close-to-zero cost is possible. The system requires relatively flat impedance curves for the rear speakers to work properly, which was often the case in the tube-amplifier days. Tube amplifiers had a constant impedance over a wide range, and worked best with high-efficiency speakers. Later on, when transistor amplifiers were used, speakers tended to lose that design feature. (Lower impedance meant higher power output for these amplifiers, compensating for the lower efficiency of such designs.) The system worked best using a transistor-based stereo amplifier, low-efficiency front speakers, and high-efficiency, constant impedance rear speakers.

Surround Matrix

The encoding was unusual in that, like the Stereo-4 system, it did not use 90° phase shifters.

Records

Albums

* The Flame by

The Flames The Flames was a musical rock group from Durban in South Africa. They performed across London in the late 1960s, where they met Brian Jones, Keith Moon, Keith Richards, Jerry Garcia, Miles Davis and Carl Wilson. They later traveled to Los Ange ...

* 4 Dimensional Sound Demonstration record (D-400)

Beach Boys Recordings

During 2016, recording engineer Stephen Desper in several online forum posts publicly refuted the common rumour that a number of

Beach Boys A beach is a landform alongside a body of water which consists of loose particles. The particles composing a beach are typically made from rock, such as sand, gravel, shingle, pebbles, etc., or biological sources, such as mollusc shell ...

recordings had been mixed and released in Dynaquad or any other four channel matrix. 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.

References

{{Quadraphonic sound Surround sound Quadraphonic sound