Stax: The heart of soul

In spring 1967 British audiences got the opportunity to experience the Stax Revue for the first time. The 13-date tour boasted a wealth of the label's talent - Otis Redding, Sam and Dave, Arthur Conley, Carla Thomas and Eddie Floyd - performing with the musicians who had recorded dance-floor and jukebox favourites such as "Knock on Wood" and "You Don't Know Like I Know".

In the six years since former country-fiddle-playing bank clerk Jim Stewart and his sister Estelle Axton had renamed their tiny Memphis-based label, Satellite, Stax had come to epitomise Deep Soul. The tour was thus a defining moment for British fans - young mods, future stars, even the Beatles - turned out to hail the visiting emissaries.Some were surprised to discover that the blend of rolling organ, punchy horns, compulsively danceable bass and drums that defined the Stax sound was created by a mix of black (organist Booker T Jones and drummer Al Jackson) and white (writer, guitarist and A&R man Steve Cropper and bassist Donald "Duck" Dunn) musicians. Augmented by the Memphis Horns duo of Wayne Jackson and Andrew Love, Booker T and the MGs were the beating heart of the Stax studio - a disused cinema on McLemore Avenue, in the heart of Memphis's black ghetto. In the face of Southern supremacists battling civil rights activists, Stax's cross-cultural ethos was revolutionary - black and white musicians united behind an array of black stars.

The cultural impact was keenly felt across the States and, as the new BBC4 series Soul Britannia explains, in the UK. The Rolling Stones covered hits by Otis Redding and Rufus Thomas. The Beatles' "Baby You Can Drive My Car" paid homage to the label's sound, though the special magic of the McLemore Avenue studio remained just out of reach when plans for the band to record there were abandoned. Stax ("Soulsville USA") was gutsy, earthy and defiantly downhome, while the era's other great black American label, Motown ("Hitsville USA"), specialised in crossover sophistication.

The charismatic and indefatigable Otis Redding had no need for Motown's charm school or etiquette lessons. In 1966, he had easily won over British audiences on a short tour that climaxed in a Ready Steady Go! special, promoting his latest, and perhaps the greatest of all Stax albums, Otis Blue - Otis Redding Sings Soul. The album was recorded in an astonishing one-day session on 7 July, 1965, in the middle of a Memphis heat wave. The studio had no air conditioning and Otis was stripped to the waist, driving the band and humming the stabbing and soaring horn parts on originals such as " Respect" and "I've Been Loving You Too Long".

Determined to pay tribute to his recently deceased mentor, Sam Cooke, Redding included three of his compositions, most notably an unforgettable rendition of the civil rights anthem "A Change Is Gonna Come". Otis Blue relied heavily on cover versions (including "Satisfaction", learned on the spot from the recently released Stones single). But four decades later, it sounds as compelling and individual an album as any in soul history. Otis Blue marked the point where Redding became, in the words of Stax founder Jim Stewart, "more than just a soul singer and became the superstar you always dream of working with". It also marked the point where Jerry Wexler, whose Atlantic label had signed a distribution deal with Stax, began to bring Atlantic-signed acts to Stax. In some cases, the results were released on Stax (Sam and Dave); others remained on Atlantic (Wilson Pickett).

The extended Stax family was treated like visiting royalty by the UK press and public in 1967. Cropper was shocked to see crowds awaiting their plane at Heathrow. The Beatles sent limos to meet them and broke from recording sessions to complete Sergeant Pepper to spend a night on the town with Otis. Upon meeting Cropper, all four Fabs reportedly stood in line and bowed from the waist in unison.

The Stax UK shows proved unforgettable. The competitive spirit undoubtedly helped turn up the heat, and every night Otis felt dutybound, as headliner, to top the outrageous theatrics of the stars who preceded him. In London, Arthur Conley thrilled the audience with a spectacular James Brown-style exit. In Glasgow, future Average White Band guitarist Hamish Stuart was "totally blown away by the passion, the showmanship and the drama. Sam and Dave were very dramatic, a lot of turning, posing and all the rest of it."

Often it was the force and strength of the individual characters on the label that made Stax output so remarkable. Writers responded to the imposing personalities of the stars to pen some of their most memorable songs. The songwriting team of Isaac Hayes and David Porter always cooked up " something soft" for Carla Thomas and "something coarse" for Sam and Dave. Redding's signature tune, "Mr Pitiful", was developed by Cropper from a title conferred on Otis by a local because of his mastery of the pleading ballad. Together with "The Big O", he penned the fast-paced statement of intent on a 10-minute drive to the studio, recording it soon after.

Like so much 1960s pop, Stax moved at an accelerated pace, revelling in the hothouse atmosphere.The odd fluffed vocal line, an imprecise tuning or a dropped note were often overlooked - in favour of retaining the all-important feel and atmosphere.

Shortly after his return from Britain, Otis stole the show at the Monterey pop festival. But back home in Georgia, he found his achievements counted for little at a restaurant where the waitress informed him: "You know we don't serve niggers here."

"(Sittin' on) the Dock of the Bay", a stunning but introspective acoustic ballad, marked a significant break with the Stax sound and showed that Otis had the artistry and ambition to map out the future. But what that future may have been remains one of the great "what ifs" in pop history. By the time the song had become Redding's first US pop number one, in spring 1968, he was dead, aged 26, his plane having crashed en route to a concert.

For Cropper and many others, Otis's death spelt the beginning of the end of the Stax dream. There were more great records and even more ostentatious stars to come after Redding's death. (Isaac Hayes was to make the move from arranger, writer and keyboard-player, cast himself as the shaven-headed "Black Moses" and compose Shaft; he became the label's biggest-ever, platinum-selling act.)

But the assassination of Martin Luther King and the arrival of a new regime at the label resulted in divisions that never healed. King was shot at the Hotel Lorraine, Memphis, on 4 April, 1968, a regular after-hours hangout for Stax employees. Shortly after the news of King's death spread, William Bell was among several black musicians who had to escort Steve Cropper and Duck Dunn past an angry mob outside the McLemore Avenue studio.

For Booker T, it marked the point where everything changed "for relations between the races in the South". Three years later, Cropper was the first of the inner circle to leave, the MGs split and the McLemore Avenue studio was no longer responsible for the Stax sound. The label's informal atmosphere changed - new executives flaunted firearms, the Stax open-door policy ended. Despite buoyant sales and the 1972 Wattstax Festival in LA(hailed as "the black Woodstock"), the feeling that Memphis's home-grown gold was being drained away persisted, with accusations of financial impropriety, law suits and tax investigations.

Stax artists were often meagrely rewarded for their sweat-soaked labours (at the time of his death Redding was rumoured to be planning to leave the label) and many suffered from the inevitable side effects of the non-stop work rate. By the early 1970s, Sam and Dave were at each other's throats and both were junkies. In 1975, the great Al Jackson was shot dead in his Memphis home.

Stax struggled on but finally closed its doors in 1976. Yet such potent musical history never lies dormant for long. In the years since 1976, the Stax sound has been revived in movies such as The Blues Brothers and The Commitments. This year marks 50 years since Stewart and Axton launched the Satellite label. A two-CD set will be released to celebrate, and the Stax imprint is also being relaunched with new releases from Isaac Hayes and Angie Stone. In Memphis, the anniversary will be marked at the Stax Museum of American Soul Music, built on the site of the old cinema studio.

In Memphis, music historian Robert Gordon's forthcoming Stax documentary, Justin Timberlake is among stars who attest to the label's lasting influence. Forty years since its finest arrived on British shores, Stax still symbolises a heartfelt authenticity and deep soulfulness that time cannot erode.

'Soul Britannia' starts at 9pm on BBC4 tonight. The Barbican Soul Britannia Concerts take place tonight, tomorrow and Sunday (which features Stax stars Sam Moore and Eddie Floyd). The musical tribute to Stax/Atlantic, 'Sweet Soul Music', begins its UK tour this month