Question: Who are the engineers that worked on the movie Sound City?
About the article "Sound City (film)", section "Technical".

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In 1919, De Forest filed the first patent on his sound-on-film process, which improved on the work of Finnish inventor Eric Tigerstedt and the German partnership Tri-Ergon, and called it the De Forest Phonofilm process.
Phonofilm recorded sound directly onto film as parallel lines of variable shades of gray, and later became known as a "variable density" system as opposed to "variable area" systems such as RCA Photophone.
These lines photographically recorded electrical waveforms from a microphone, which were translated back into sound waves when the movie was projected.
From October 1921 to September 1922, DeForest lived in Berlin, meeting with the Tri-Ergon developers and investigating other European sound film systems.
He announced to the press in April 1922 that he would soon have a workable sound-on-film system.
On 12 March 1923, DeForest presented a demonstration of Phonofilm to the press.
On 12 April 1923, DeForest gave a private demonstration of the process to electrical engineers at the Engineering Society Building's Auditorium at 33 West 39th Street in New York City.
This system, which synchronized sound directly onto film, was used to record stage performances (such as in vaudeville), speeches, and musical acts.
In November 1922, De Forest established his De Forest Phonofilm Company at 314 East 48th Street in New York City, but none of the Hollywood movie studios expressed any interest in his invention.
De Forest premiered 18 short films made in Phonofilm on 15 April 1923 at the Rivoli Theater in New York City.
He was forced to show his films in independent theaters such as the Rivoli, since Hollywood movie studios controlled all major theater chains.
De Forest chose to film primarily short vaudeville acts, not features, limiting the appeal of his process to Hollywood studios.
Max Fleischer and Dave Fleischer used the Phonofilm process for their Song Car-Tune series of cartoons—featuring the "Follow the Bouncing Ball" gimmick—starting in May 1924.
De Forest also worked with Freeman Harrison Owens and Theodore Case, using Owens's and Case's work to perfect the Phonofilm system.
However, DeForest had a falling out with both men.
Due to DeForest's continuing misuse of Theodore Case's inventions and failure to publicly acknowledge Case's contributions, the Case Research Lab proceeded to build its own camera.
That camera was used by Case and his colleague Earl Sponable to record President Coolidge on 11 August 1924, which was one of the films shown by DeForest and claimed by him to be the product of "his" inventions.
Seeing that DeForest was more concerned with his own fame and recognition than he was with actually creating a workable system of sound film, and because of DeForest's continuing attempts to downplay the contributions of the Case Research Lab in the creation of Phonofilm, Case severed his ties with DeForest in the fall of 1925.
Case then negotiated an agreement for his patents with studio head William Fox, owner of Fox Film Corporation, who marketed the system as the Fox Movietone process.
Shortly before the Phonofilm Company filed for bankruptcy in September 1926, Hollywood introduced a new method for sound film, the sound-on-disc process developed by Warner Brothers as Vitaphone, with the John Barrymore film "Don Juan", released 6 August 1926.
In 1927 and 1928, Hollywood began to use sound-on-film systems, including Fox Movietone and RCA Photophone.
Meanwhile, a theater chain owner, Isadore Schlesinger, acquired the UK rights to Phonofilm and released short films of British music hall performers from September 1926 to May 1929.
Almost 200 short films were made in the Phonofilm process, and many are preserved in the collections of the Library of Congress and the British Film Institute. 
Beau Borders was born and raised in New Jersey.
He became active in motorsport scene at early age.
Aged of fourteen Borders was the youngest Crew Chief in the history of IMSA.
He then worked in his fathers racing team.
Besides his passion for motorsport he also has a successful career as sound engineer.
He entered the movie industry in mid-1990s.
Borders worked at George Lucas’s Skywalker Ranch.
In the following years he collaborated on movies like "Titanic", "The Lord of the Rings" and "Transformers".
Borders and his fellow sound engineers Andy Koyama and David Brownlow are nominated for an Academy Award for Best Sound for the 2013 film "Lone Survivor".
Beau Borders resides in Venice Beach, California. 
Large-scale sound reinforcement systems are designed, installed, and operated by audio engineers and audio technicians.
During the design phase of a newly constructed venue, audio engineers work with architects and contractors, to ensure that the proposed design will accommodate the speakers and provide an appropriate space for sound technicians and the racks of audio equipment.
Sound engineers will also provide advice on which audio components would best suit the space and its intended use, and on the correct placement and installation of these components.
During the installation phase, sound engineers ensure that high-power electrical components are safely installed and connected and that ceiling or wall mounted speakers are properly mounted (or "flown") onto rigging.
When the sound reinforcement components are installed, the sound engineers test and calibrate the system so that its sound production will be even across the frequency spectrum. 
Gonzalo Gavira (October 30, 1925 – January 9, 2005) was a Mexican movie sound technician.
He formed part of the team that won an Oscar for the movie "The Exorcist" in 1973.
Outside of Mexico he worked on more than 60 other films, including the disaster movie "The Towering Inferno" and western "El Topo", as well as Sergio Leone's "The Good, The Bad, And The Ugly".
While working in the United States he always worked with an assistant named Ruben C. Bustamante, Mr. Gavira referred to him as invaluable.
In 1975 he was awarded the Silver Ariel, which is the highest award that can be received from Mexican theatre.
He died in 2005, reportedly from circulation problems.
Along with working together with director Sergio Leone, Gonzalo Gavira worked with William Friedkin, Alejandro Jodorosky (The Holy Mountain) and the great Cantinflas, who on many occasions classified Mr. Gavira as a genius.
Once upon meeting Lee Marvin, Gonzalo Gavira asked Mr. Marvin to autograph a twenty dollar bill.
Lee Marvin refused, stating he would rather use that twenty to buy some drinks later, they became fast friends.
Mr. Gonzalo Gavira worked on approximately 80% of all movie features made in Mexico.
"Letters from Marusia" was nominated for Best Foreign Film at the 1976 Oscars and "Canoa" won Picture of the Year 1976 in Mexico City. 
Willis O'Brien, creator of the highly regarded effects for the original "King Kong", provided the same services here, albeit on a much smaller budget.
Pete Peterson, who worked with O'Brien on "Mighty Joe Young" and would again on "Behemoth, the Sea Monster", did most of the actual hands-on animation.
O'Brien borrowed heavily from other previous movies for the special effects in this film.
The models used for the trapdoor spider and the giant worm with tentacles are the same ones that were used in the famous "Lost Spider Pit Sequence" from the original "King Kong".
The sounds made by the scorpions are a reuse of the ant sound effect from the movie "Them!".
A large-scale scorpion "head" was used for closeup reaction shots, but the head's human-like features distracted from the realism of O'Brien's animated models.
The steam locomotive pulling the train that is attacked is clearly a Lionel Corporation toy train.
The steam locomotive's tender clearly retains its "Lionel Lines" markings.
Three shots of scorpions attacking the city toward the end of the film are actually just empty traveling mattes as the producers had run out of money when the time came to composite these scenes.
This and numerous other flaws in the film were the subject of episode 113 of movie-mocking TV series "Mystery Science Theater 3000".