The 31-year-old has been recuperating from surgery in March for carpal tunnel syndrome, which prevented him from playing for months. Incubus therefore cancelled 23 European and South American engagements.
The injured Einziger began studying music privately for five days a week. "I started working on [the symphony], and I learned very quickly that there are a lot of gaps in my music knowledge," he said.
The band's upcoming tour schedule should also give him ample time to work on the untitled composition, which he expects to be in three movements and 40 minutes in length.
The Grammy-nominated musician says he understands that the classical work's appeal should not depend on it having been written by a rock musician.
"It has to stand up to the work of other composers as well ... and [is] a pretty hefty task for me to endure."