Densmore told Billboard:
What were the influences that shaped the Doors' sound and what does
each member of the band bring to the table?
John Densmore: Ray grew up in Chicago so he had the blues, Muddy Waters and
all that. He also had classical training. That was pretty cool. That
was invoked in the intro to "Light My Fire," which was very kind of
Bach-like. Robby had a flamenco and folk music background. I was so
enamored with watching Robby's fingers crawl across the flamenco
guitar strings like a crab.
I'm a jazz guy and Ray was also into jazz, so when we met we talked
about [John] Coltrane and Miles [Davis]. I think that influence gave
me freedom. Like in "When the Music's Over," I just stopped playing
the beat, and I would just comment on Jim's words percussively, out of
rhythm, like we were having a conversation. I got that from listening
to Elvin Jones and John Coltrane.
And then there was Jim, Mr. Literary, who had read every book on the
planet, but didn't know anything about music and how to write songs
and trusted us. Therefore, we were a total democracy.
We shared everything—writing credits, veto power. Jim had melodies as
well as words. He didn't know how to play a chord on any instrument,
but he had melodies in his head. To remember the lyrics he would think
of melodies and then they would stay in his head. He had melodies and
lyrics in his head, and he would sing them a cappella, and we would
eke out the arrangements.
With regards to the source, the intro to the article states:
The interview is from Billboard's November 4, 2006 issue and was
conducted on the occasion of Ben Fong-Tores' oral history "The Doors
by the Doors" (Hyperion) as well as the release of six-CD box set