Here's the first of a two-part investigation into the role of the record producer by John Morrish, in which no fader is left unpushed. This month, the American lot — from Elvis echoes to walls of sound.

We all know what a producer does, but do we know why? The producer piles on instruments and effects and echo, but in response to what? The song? Fashion? Simple personal preference?

All those are true, of course, but any producer working in the last three decades has inevitably been working in a growing tradition. The very best of them take from that common language and develop a voice of their own that in turn becomes part of the shared tradition again.

Those are the producers we want to look at. Not the most successful, necessarily, but those who took themselves seriously and built themselves a sound.

Let us start with Sam Phillips, a one-time radio engineer in segregated Memphis, Tennessee, a white man with a deep love of black music and a plan to bring the two sides together and make a million dollars. In a break from his usual blues sessions, Sam recorded a birthday ditty by an astonishing vocal mimic called Elvis Presley. One tiny strain in the mass of undigested vocal influences displayed by the 19-year-old in a subsequent audition, was an authentic sounding blues voice. More than that, a voice which made listeners appreciate the common heritage of poor Southern whites and their black counterparts.

Sam's claim to immortality is that he dug out that voice, wrapped it up with the hottest, weirdest-sounding white band you ever heard, and put it on tape. There wasn't much else he could do: no sampling, no FM synthesis, no effects rack. All he had was echo, but what echo. The original voice of rock'n'roll, as inescapable apart of the music today as it was in 1955.

Sam found his dream, the white boy who could sing like a black bluesman: but he sold Elvis to RCA and a sad career of films and family entertainment before the million dollars came in. Still, through the miracle of sound recording, those first moments of wonder are with us today. BUY THIS RECORD: "The Elvis Presley Sun Collection" (RCA NL 42757).

After Elvis came a string of imitators, but it was Buddy Holly's good fortune that he found a producer who broadened his scope beyond simply being a clone. Norman Petty called Holly "a diamond in the rough" and set about polishing his sound. Multitracking manipulation of echo, and weird instruments all played their part in developing a wistful and plaintive side to the new music on "Everyday", for instance. The contrast with the simple "photographic" technique of a Sam Phillips recording in one take a series of performances could not be more acute. The contrast was to re-assert itself throughout the history of production. It lives today, even in the era of the sequencer and the mag-linked multitrack.

So much for white men singing the blues, or variants of that theme. Black men were doing the same, with varying degrees of success. One white man who took up their cause was Leonard Chess, a man who seems to have known nothing much about music, but who extracted extremely interesting performances from a variety of black blues and rock artists by cajoling and/or bullying. Chuck Berry stands out, of course, recording in the Chess studios which employed a drain pipe to create the authentic sound Leonard Chess had heard in his own garage. "My father wanted drum, drum, and more drum," Marshall Chess told Peter Guralnick, "I think he was responsible for doing that to the blues, to bring out a heavy beat."

Away from the world of "drum, drum and more drum", a lucrative market for teenage pop was beginning to develop, and black artists were having a tough time because white acts would "cover" (read steal) their songs, arrangements and all.

There were various ways of escaping from this, but Jerry Leiber and Mike Stoller found some of the most successful. For the Coasters, a black vocal group, they produced a series of what they termed "playlets" based on incidents from teenage life and developed in such a way as to bring out the dramatic possibilities inherent in the vocal group format. "Riot in Cell Block No. 9" was the first.

Uniquely among the producers mentioned here, Leiber & Stoller came up with a second, entirely different, sound. Presented with Atlantic's singers The Drifters, they wrapped them up in a curious concoction of pseudo-Tchaikovsky strings and trendy Latin beat to produce "There Goes My Baby", one of the most seriously weird records ever to top the US charts. Then they let the formula run, having invented something not dissimilar to the sweet soul music of the midSixties.

Soul, of course, was not one man's invention any more than rock'n'roll had been. But that's not to play down Jerry Wexler's contribution any more than it is to discount the role of Sam Phillips in the invention of the earlier form. As a partner in Atlantic Records, Wexler was there or thereabouts in all the most significant developments in black music for at least 15 years. As a producer he made a number of significant contributions of his own, threading an interesting path between what you might call "purity" and "production".

Firstly, he eased Ray Charles, till then an immensely talented enigma, into a gospel-based style that suited him and astonished everybody else. "What'd I Say" is one of those songs that retains the power to surprise, even to shock, to this day. Secondly, he invented the distinctive Stax backbeat during his production of Wilson Pickett's "In the Midnight Hour". And finally, he rescued Aretha Franklin from a wasted career as a singer of show tunes and standards and made her truly the queen of soul.

Somehow Atlantic seems to have arrived at the idea of catering for the older, more sophisticated record buyer, and this was to place it in good stead when the hippie era descended on America. But Berry Gordy's Motown stable was always interested in the kids and in dance music. Gordy's contribution as a producer was more a case of discovering what did not work before finding what did. In the end, it was other hands who developed the Motown sound as it is universally recognised and widely imitated. Smokey Robinson produced a series of delicate soul ballads, Norman Whitfield provided the answer to the psychedelia of the big chart artists of the day, but it was the team of Holland-Dozier-Holland who pounded out the big beat for the Supremes and the Four Tops.

Few of the producers we have mentioned so far would have thought of themselves as self-conscious artists, but that was exactly how Phil Spector and his young emulator Brian Wilson chose to develop their careers. Advancing on parallel paths, they struggled to attain the kind of artistic independence appropriate to people with such a powerful confidence in their own abilities. Spector learned his perfectionism as a session guitarist on the Leiber & Stoller Drifters sessions, but began, in his own work, to build a sound much bigger than they ever dreamed of. The aim was to make a series of inimitable recordings, thus stopping the cover-version merchants before they got off the starting blocks.

The method was mono. Three tracks were used, one for the band, including at least five guitarists, two pianos, three basses, two trumpets, two trombones, two saxes, a drummer and all manner of exotic percussion; one for the vocals; and one for strings. And then he'd mix down to the loudest mono that anybody had ever heard.

The use of mono was one thing that Spector shared with Brian Wilson, although in Wilson's case it was a matter of necessity, arising out of a damaged ear. Brian Wilson is unique among the producers featured here in producing a volume of influential work for just one band: his own. The Beach Boys changed from a happy-go-lucky bunch of high-school kids to a powerful and wealthy recording unit with unprecedented privileges. Brian made them the first band to handle their own recordings and to have their own label. His masterpiece is undoubtedly "Pet Sounds", a pre-Sergeant Pepper's song-cycle of complexity and richness. He was 24 when he did it and received Paul McCartney's congratulations on "God Only Knows": the best song ever, I think he called it.

In a bid to top that (and everything else) Brian, a weird former prodigy called Van Dyke Parks, and a lorry-load of mind-expanding substances, set to work on "Smile," a concept album that started off with the intention of being about everything and got bigger and bigger until it burst. We got "Good Vibrations" and the exquisite "Heroes and Villains", and a lot of bits and pieces that made almost no sense at all.

Even now, bootlegs appear, strange chaotic, sometimes beautiful. Brian Wilson himself was (is?) a man of prodigious natural gifts who has never equalled the work he did at age 23. These days he leads a curious shadow-existence as a sort of talisman for his band of terminal good-timing rock'n'rollers. Sad is not the word for it.

Meanwhile, in Britain.... no, let's wait for next month.