Final answer:
In Elvis Presley's recordings at Sun Records, the standard accompaniment used was an acoustic rhythm guitar, an electric lead guitar, subdued drums, and the string bass, creating the unique rock 'n' roll sound that was distinctive to Memphis at the time.
Step-by-step explanation:
The standard accompaniment for Elvis Presley's recordings at Sun Records included an acoustic rhythm guitar, an electric lead guitar, subdued drums, and the string bass. Presley's music at Sun Records was characterized by a combination of electric instruments with the rich sounds of various genres such as gospel, blues, country, and rhythm and blues (R&B), which collectively helped give birth to the new sound of rock 'n' roll. This new musical style was an instant success, capturing the hearts of teenagers across the nation with its heavy rhythm, simple lyrics, and catchy melodies.
During his time at Sun Records, Elvis became known for his innovative blend of music, absorbing influences from his upbringing in Memphis, which was at the crossroads of music from the lower Mississippi Delta and Kentucky. The result was a unique sound that combined the blues and bluegrass into rock 'n' roll, a genre which at the time, was mainly unique to the Memphis region.