When artists die mid-career, they seal their creative selves in aspic, relieving us from having to watch them croak ignominiously towards their dotage. Bob Dylan, as one would expect from a singer who will always defy expectations, has denied us this, forcing us to work with him as he moves from standing with his guitar at the front of the stage to standing behind the piano somewhere at the back, tantalisingly out of view; from relating to his audience to ignoring it completely; from singing whole phrases to using economical, three-syllable motifs. Still, we come back for more.
Much has been written about Dylan's lyrics, but his recordings offer more than words. His extraordinary voice and delivery bind them to melody and his singing inspires, provokes and divides. When I want to remind myself of his glorious capacity to go beyond the horizon vocally, I listen to "Isis" for those swoops that lend accent and colour to the melody and the surprising, sermonising stresses.
Dylan well understands the emotional power of the voice - why the vocal performances of Sun Records artists such as Elvis Presley, Carl Perkins and Roy Orbison pulsate with vitality; why, as he wrote in 2004, Johnny Cash's singing was "full-tilt and vibrant with danger". Dylan's voice is crafted from something similar.
All singers make stylistic choices. Dylan's are informed by the vocal qualities of the folk musicians he admires and the bluesmen and country singers he has soaked up. On the 1962 recording "Baby Let Me Follow You Down", the country-folk nasality and timbre, phrasing, trademark glissandi to and from notes and the pitched speak-singing are already there, though a little self-conscious, as if waiting for the summons from the muse. When that physical voice joins forces with the poetic voice on his second album, The Freewheelin' Bob Dylan, something alchemical happens.
All of the early recordings place the voice up front in the mix. In songs that display what the writer Michael Gray calls "the genius of his singing", where the silences, sighs and audible intakes of oxygen contribute to what Dylan once described as "exercises in tonal breath-control", every word has clarity and is given its required length and pitch. There's immense musicality in this - it is driven, skilful, artful and soulful.
Dylan first blew me away with "It's Alright, Ma (I'm Only Bleeding)". By the time this was recorded, the intimacy of the café and concert hall had started to give way to vocally stressful rock'n'roll stages. The demand on the voice had changed. With his music now heavily amplified, his singing had to cut through drums, keyboards and electric guitars. It was harder and darker, though it remained lyrical and fluttered with rhythm. The 1965 recording of "Love Minus Zero/No Limit" is positively romantic.
Throughout Dylan's life and musical explorations, his voice has retained its strength and commitment. But since Time Out of Mind (1997), it has had a roughness that brings with it a deeper, more distinctive flavour, like an aged whiskey, and an authority that demands attention. In Nat Hentoff's sleeve notes for The Freewheelin' Bob Dylan, the then 21-year-old singer speaks about his delivery on "Don't Think Twice, It's All Right": "I don't carry myself yet the way that Big Joe Williams, Woody Guthrie, Lead Belly and Lightnin' Hopkins have carried themselves. I hope to be able to someday but they're older people." Now, he is older.
Great vocalists divide listeners. Powerful timbres are like marmite: they're not for the faint of heart. Dylan is no Dean Martin - there's nothing easy listening about him - but his voice is up there with the best. Like Cash, Édith Piaf, Maria Callas and Nina Simone, his concern is direct and visceral communication. Dylan may turn away from us on stage these days, but he continues to bewitch us with a voice of burned sand, blowing across the porches, gallows, bars, altars and stories of a mythical America.
“Man in the Long Black Coat: Barb Jungr Sings Bob Dylan" (Linn Records) is out on 30 May