Final answer:
Jimmy Page, the guitar player from the Yardbirds, added a progressive sound to his music in the 1960s and continued to seek new sounds throughout his career.
Step-by-step explanation:
The guitar player from the Yardbirds who added a progressive sound to his music in the 1960s and continued to seek new sounds in his advanced years is Jimmy Page. He is known for his innovative and experimental guitar playing, incorporating various genres like gospel, blues, country, jazz, and R&B into his music. Page's willingness to learn new techniques and push musical boundaries has made him one of the most influential guitarists in rock music.