Dynaquad , or DY , was a matrix decoder 4-channel quadraphonic sound system developed by Dynaco in 1969.
27-520: 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 , 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
54-616: A built-in Hafler circuit. Philips had a similar circuit in their two-channel receivers. Many receivers from middle price brands had such circuits, but often without a volume control for the rear channels. More expensive brands seldom had Hafler or similar circuits, because they thought such circuits increased the distortion of the sound. Most of Marantz ' four-channel receivers had a variable matrix called Vari-Matrix (not to be confused with Sansui's QS Vario Matrix) that could simulate four-channel stereo from two-channel sources in different ways and
81-434: A major quotidian brand of American teenage life. The company went out of business after being sold to Stern Electronics in 1982. Automated musical equipment, such as coin-operated phonographs and orchestrions , was manufactured under the J.P. Seeburg and Company name for most of its early years. Until 1956, the company was family-owned. The company was founded by Justus Percival Sjöberg from Gothenburg , Sweden. He moved to
108-767: A number of Beach Boys 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. 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 system works using similar principles. Named after its early proponent audio engineer David Hafler ,
135-415: 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
162-489: A total of 100 selections, more than four times greater than previously available. In 1950, Seeburg introduced the first commercial jukebox designed to play the then-new 45 rpm records. They increased the number of records from 50 to 100 in 1955, eventually settling on 50 or 80 per machine after 1958. The classic M100C is featured early in the opening of the Happy Days TV series, although the actual spinning 45 rpm record shown
189-403: Is being played on a Rock-Ola. The Seeburg "Select-O-Matic" mechanism stores the records in a linear magazine and plays them vertically clamped to a flywheel turntable. The selected record is pushed forward from behind, then clamped in place. The tonearm is likewise oriented vertically and has a stylus on each side. The tonearm assembly shifts right or left depending on which side of the record
216-585: Is being played. In machines manufactured during the 1950s, the entire mechanism was visible to the user. Later machines concealed the mechanism in favor of graphics and lights, but internally it was essentially the same mechanism. Seeburg started diversifying its product lines in 1959 with the introduction of background music players such as the Seeburg 1000 , which used special 9-inch, 16⅔ rpm records. Seeburg acquired Williams (pinball and other games) and Gulbransen (electronic organs and drum machines) in 1964 and
243-446: Is the type of quad setup used by Seeburg jukeboxes that had quadraphonic sound. The Hafler circuit is capable of partially decoding a Dolby Surround track since both share the same operating principles (based on sound phase differences). Yet the Hafler circuit lacks the proper separation or balance between channels of a true Dolby Pro Logic decoder. In the early and mid-1970s, for example, Ferguson made two-channel receivers with
270-508: The H. N. White Company (King brass and woodwind instruments) in 1965. Gulbransen remained in production through the late 1960s, with limited production (mostly drum machines) revived during the 1970s. In 1965, the Seeburg Corporation announced that it was establishing a new music performance rights organization to compete with ASCAP, BMI, and SESAC. The society was called Coin-Operated Phonograph Performance Society (COPPS). The plan
297-519: The United States after graduating from Chalmers University of Technology and used an Americanized spelling of his surname for the company. The Seeburg Style L (Lilliputian) Nickelodeon was a coin-operated 54 note player piano with its suction pump driven by an electric motor. An example can be seen at the Musical Museum , Brentford, England. In the early days of the jukebox, the 78 rpm record
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#1732895675686324-410: The arrival of gramophone records, the company developed a series of "coin-operated phonographs." Before it began manufacturing its signature suite of jukebox products, Seeburg was considered to be one of the "big four" of the top coin-operated phonograph companies alongside AMI , Wurlitzer , and Rock-Ola . At the height of jukebox popularity, Seeburg machines were synonymous with the technology and
351-436: The circuit exploits the high amount of stereo separation between Left and Right channels and sound phase . This type of system is called 2:2:4 , since the rear channels are simulated from a two-channel stereo track, with no actual extra tracks encoded. The rear channels will playback out of phase sounds, while the forward channels are unaffected. Using the circuit typically reduces stereo separation by only about 2 dB and
378-473: The company began. The production assets were sold to Stern Electronics , who began producing "Stern/Seeburg" jukeboxes. The parts department stock was purchased by Los Angeles-based Jukeboxes Unlimited in September 1980. In March 1984, former Seeburg employees and a group of investors formed "The Seeburg Phonograph Company" and acquired its production assets from Stern, which was going out of business. It became
405-512: The first manufacturer to produce a CD jukebox. It remained in operation for a few years and several models of CD jukeboxes were made during that period. Eventually, the company closed and now nothing remains. The Seeburg name lived again on Wurlitzer 1015 reproduction CD jukeboxes produced in Mexico for a short time. As of February 2010 , a touchscreen digital jukebox conversion kit bearing the Seeburg name
432-465: The format. The competing Stereo-4 system was very similar and can be considered as compatible, as both use very similar decoding matrixes (based on the Hafler circuit ). 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
459-557: 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
486-500: The listener could adapt the sound with a control. The Vari-Matrix could also, with good results, play all matrix records. Technics by National Panasonic had a similar matrix decoder with two controls. Tandy Corporation used this circuitry for Quatravox matrix decoders used in their Realistic branded Hi-Fi systems sold at their Radio Shack stores in the US. In the early 1970s, the words "ambiophony" and "ambiophonic" were synonymous with
513-459: 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. The encoding was unusual in that, like the Stereo-4 system, it did not use 90° phase shifters. During 2016, recording engineer Stephen Desper in several online forum posts publicly refuted the common rumour that
540-444: The musicians mostly are in synchronous phase. Thus, if rear speakers are fed with the difference between the stereo channels, audience noises and reverberation from the auditorium may be heard from behind the listener. This can be most easily achieved by wiring two similar additional rear speakers in series between the live feeds (positive terminals) from the stereo amplifier. Alternatively, one rear speaker can be used on its own. This
567-413: 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
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#1732895675686594-413: The phrases "quadraphonic" and "four-channel stereo". But around 1973 the words ambiophony and ambiophonic were used to describe simulated four-channel stereo of the Hafler type. Ambiophonic could also mean the so-called concert hall sound in opposite to a surround sound with instruments all around the listener. The concert hall sound means the listener hears all the instruments from the front, whereas
621-470: The rear channels are mainly used to give the listener the acoustic effect of sitting in a concert hall. (Ambiophony or ambiophonic sound should not be confused with Ambiophonics or Ambisonics .) Seeburg Corporation Seeburg was an American design and manufacturing company of automated musical equipment, such as orchestrions , jukeboxes , and vending equipment. Founded in 1902, its first products were Orchestrions and automatic pianos but after
648-400: The rear speakers are only required to reproduce a limited frequency range (allowing them to be smaller and cheaper). The rear sound level in a live performance recorded in stereo is reproduced about 7 dB below the front level, but clearly audible. The rear ambient sounds, applause, and coughs from the audience are sometimes received out of phase by the stereo microphones, while sounds from
675-509: Was for Seeburg to make recordings solely for play in jukeboxes. During the 1970s Seeburg was faced with debt and a declining market for their music products. The corporation headed into bankruptcy in 1979 and was broken up in 1980. In Seeburg's reorganization effort, jukebox production came under the "Seeburg Phonograph Division," which the court closed in September 1979. Following the demise of Seeburg Phonograph Division, ownership of Seeburg's assets passed to their creditors and liquidation of
702-424: Was standard and until 1949, only 10 to 24 selections could be played on one machine. The Seeburg Symphonola jukebox of 1938 (illustrated below) has 20 10" 78 rpm records and can only play one side of each. An example of this instrument can be seen and heard at the Musical Museum , Brentford, England. The small number of selections changed with the Seeburg model M100A, which could play 50 records front and back for
729-564: Was used on the Electrovoice Stereo-4 system). 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 started to use it as an encoding/decoding matrix (4:2:4 format) in 1971. There were few albums released in
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