One of my fondest childhood memories is of my father coming into the living-room one morning and announcing to my oldest sister: “Come quickly – there’s a very sick man in your room.” That sick man was none other than Bob Dylan himself (she had left her favourite tape running). After that it always felt as if Dylan’s incorrigible voice had invaded our house.

A certain disruptive, restless quality has always been at the heart of rock, and it seems to be channeled most effectively through voices that are not smooth or conducive to easy listening. The talent shows that obsess TV viewers today are designed as family entertainment, and they tend to reward voices that have the broadest possible appeal in small doses.

Dylan’s voice, by contrast, has always had the raw power to polarize any audience, and the same is true of surprisingly many singers who have something to say. Listening to Dylan’s Highway 61 Revisited or Randy Newman’s Sail Away, Tom Waits’ Swordfishtrombones or Leonard Cohen’s I’m Your Man for the first time can be unsettling: why would anyone who can hold a tune deliberately sing like that? The answer is not always the same, but in Dylan’s case at least the vocal style he cultivated was a perfect fit for his subject-matter and his particular stance.

That position is perhaps most clearly defined in the unparalleled Chimes of Freedom from his 1964 Another Side album. The song is dedicated to a host of the dispossessed and down-trodden that comes to include “every hung-up person in the whole wide universe.” There is nothing in popular music of the past five decades that surpasses it for sheer lyrical ambition, and its slightly ragged vocal delivery adds to the effect, as Dylan’s voice strains to articulate a vision at the limits of language: “Tolling for the rebel, tolling for the rake / Tolling for the luckless, the abandoned and forsaked / Tolling for the outcast burning constantly at stake / And we gazed upon the chimes of freedom flashing.”

Rebels and outlaws, of course, had been romanticized in popular song for centuries. Dylan inherited a host of such characters from the plain-spoken Woody Guthrie. But where Guthrie’s outlaws are noble working-class heroes, Dylan includes both the rebel and the rake in one line.

The inclusion of the rake is significant: Chimes of Freedom was a folk song when it was released, but within a year Dylan had shocked his audience at the Newport Folk Festival and emerged as a rock singer that redefined rock’s subject-matter by creating ambivalent characters in worlds with no moral centre: the voice we hear in Like a Rolling Stone has a completely different texture from the one Dylan had used the previous year, and it cannot be pinned down to any fixed position. It pitches itself deliberately between notes, apparently impervious as to whether it gives pleasure or not.

These days I am often amazed in public places by the music playing on the loudspeakers, by its lack of force and distinction. Listening vicariously the other day to an array of boy bands, girl groups and light classics, I heard the sound of a culture afraid of its own shadow, a culture to which rock ‘n’ roll never happened.

I wish the sick men and women would come out.