Biography of Roberto del Rosario, Inventor of a Karaoke Machine

Karaoke machine

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Roberto del Rosario (1919–2003) was the president of the now-defunct Trebel Music Corporation, a founding member of the Filipino amateur jazz band "The Executives Band Combo," and, in 1975, the inventor of the Karaoke Sing Along System. Known as "Bert," del Rosario patented more than 20 inventions during his lifetime, making him one of the most prolific of Filipino inventors.

Fast Facts: Roberto del Rosario

  • Known For: Holds the 1975 patent for the Karaoke Sing-Along System
  • Born: June 7, 1919, in Pasay City, Philippines
  • Parents: Teofilo del Rosario and Consolacion Legaspi
  • Died: July 30, 2003 in Manila, Philippines
  • Education: No formal musical education
  • Spouse: Eloisa Vistan (d. 1979)
  • Children: 5

Early Life

Roberto del Rosario was born in Pasay City, Philippines, on June 7, 1919, the son of Teofilo del Rosario and Consolacion Legaspi. During his life, he was never forthright about his age. As a result, there are multiple reports on what year he was born, some as late as the mid-1930s. His son Ron del Rosario reported the June 1919 birthdate in a genealogical report.

Roberto never received formal music education but learned to play the piano, drums, marimba, and xylophone by ear. He was a founding member of The Executive Combo Band, a well-known amateur jazz band headed by post-World War II Filipino politician Raúl Sevilla Manglapus and architect Francisco "Bobby" Mañosa. The band started in 1957 and played in gigs all over the world, jamming with the likes of Duke Ellington and Bill Clinton. Roberto del Rosario married Eloisa Vistan and together they had five children; Eloisa died in 1979.

In Taytay, Rizal—under the business name Trebel (Treb is "Bert" spelled backwards and El is for his wife)—del Rosario manufactured harpsichords and the OMB, or One-Man-Band, a piano with a built-in synthesizer, rhythm box, and bass pedals that can all be played at the same time. He also developed and patented a singalong machine using "minus one" technology (originally on cassette tapes) in which vocals are subtracted from extant instrumental tracks.

Del Rosario is one of several people who are associated with the invention of a karaoke machine. Karaoke is a compound Japanese word from "karappo" meaning "empty" and o-kestura meaning "orchestra." Sometimes translated as "empty orchestra," the phrase means something closer to "the orchestra is void of vocals."

Music Minus One

"Minus one" technology has its roots in classical music recording. The Music Minus One company was founded in 1950 in Westchester, New York by classical music student Irv Kratka: Their products are professional musical recordings with one track, vocal or instrumental, removed, for the purpose of allowing a musician to practice along with the professionals at home. Multi-track recording was developed in 1955, and the technology to remove one track became available to professional musicians and publishers afterward, primarily to allow them to adjust the track balance or rerecord them to get a better sound. By the 1960s, "Minus one" technology was used by migrant Filipino musical personnel, who used the technology at the request of their promoters and record labels, who wanted to save costs by hiring fewer musicians.

In 1971, Daisuke Inoue was a keyboard and vibraphone backup player in a high-end Kobe, Japan, bar, and his abilities were in great demand at customer parties. A customer wanted him to perform at a party but he was too busy, and he recorded the backup music on tape and gave it to the customer. After that, Inoue assembled a team of an electronics specialist, a woodworker, and a furniture finisher, and together they built the first karaoke machine using 8-track tapes, complete with microphone and echo effect, called the 8-Juke.

Inoue leased his 8-Juke machines to working-class bars lacking the budget to hire live, in-house musicians in the nightlife hub of Kobe. His coin-operated 8-Juke machines featured Japanese standards and popular tracks recorded by backing musicians without vocals in 1971–1972. He clearly created the first karaoke machine, but didn't he patent or profit from it—and later he denied he was an inventor at all, claiming he simply combined a car stereo, a coin box, and a small amp.

The Sing Along System

Roberto del Rosario invented his version of a karaoke machine between 1975 and 1977, and in his patents (UM-5269 on June 2, 1983 and UM-6237 on November 14, 1986) he described his sing-along system as a handy, multi-purpose, compact machine that incorporates an amplifier speaker, one or two tape mechanisms, an optional tuner or radio, and a microphone mixer with features to enhance one's voice, such as the echo or reverb to simulate an opera hall or a studio sound. The whole system was enclosed in one cabinet casing.

The main reason we know of del Rosario's contribution is because he sued Japanese companies for patent infringement in the 1990s. In the court case, the Philippine Supreme Court decided in del Rosario's favor. He won the legal recognition and some of the money, but in the end, the Japanese manufacturers reaped most of the benefits by later innovations.

Other Inventions

Besides his famous Karaoke Sing Along System Roberto del Rosario has also invented:

  • Trebel Voice Color Code (VCC)
  • Piano tuner's guide
  • Piano keyboard stressing device
  • Voice color tape


Little has been reported about Rosario's death, which occurred, according to his son, in Manila on July 30, 2003.


  • "Music Minus One." Music Dispatch, 2019.
  • Roberto "Bert" del Rosario ("Mr. Trebel") Facebook.
  • The Joaquins. "Bert del Rosario is Karaoke inventor!" My Family and More, June 5, 2007. 
  • "Roberto L. Del Rosario, Petitioner, Vs. Court Of Appeals And Janito Corporation, Respondents [G.R. No. 115106]." Supreme Court of the Philippines, March 15, 1996.
  • Rosario, Ron del. "Roberto del Rosario, Sr." Geni, December 8, 2014. 
  • Soliman Michelle, Anne P. "National Artist for Architecture Francisco "Bobby" Mañosa, 88." Business World, February 22, 2019.
  • Tongson, Karen. "Empty Orchestra: The Karaoke Standard and Pop Celebrity." Public Culture 27.1 (75) (2015): 85-108. Print.
  • Xun, Zhou and Francesca Tarocco. "Karaoke: the Global Phenomenon." London: Reaktion Books, 2007.
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Bellis, Mary. "Biography of Roberto del Rosario, Inventor of a Karaoke Machine." ThoughtCo, Aug. 28, 2020, Bellis, Mary. (2020, August 28). Biography of Roberto del Rosario, Inventor of a Karaoke Machine. Retrieved from Bellis, Mary. "Biography of Roberto del Rosario, Inventor of a Karaoke Machine." ThoughtCo. (accessed June 9, 2023).