RAP / Voicing alarm: In America, close-harmony singing is threatening to overthrow rap. Lloyd Bradley tries to separate the rough from the smooth

Perhaps the one major discovery made by the television series Tom Jones: The Right Stuff was the resident vocal group, True Image. Performing the title song, backing musical guests and taking their own spotlight, the New York sextet delivered textbook displays of close harmony a cappella singing. Directly after the series ended, True Image performed to packed houses, but stirred little interest from UK record companies. Apparently, in the current soul / dance music climate, their gospel-rooted style (the term a cappella derives from the Italian meaning 'of the chapel') was a bit of a novelty - quaint, but of little commercial worth.

But things might have been very different for them back in the States. While the rap and rave-dominated UK black music market turns increasingly to studio technology to gee up un-sung vocals, its counterpart in the USA is re-embracing the multi-part harmony. The closer the better. During the past few months, American charts and record company rosters have been overflowing with school- age types who, five years ago, would have swaggered around in gold chains, industrial-sized sneakers and conspicuously-branded sportswear, bragging over beat-box backing tracks. Today, though, they're clustering round microphones, and coming on smooth in intricately arranged songs.

Boyz II Men, Guy, Joe Public, Father MC, Levert and Keith Sweat have reached platinum status in the States, while seldom nudging the British charts. It points to a vast divide between black music on either side of the Atlantic. True Image's Reginald Brisley claims the US shift after rap's decade of dominance is the result of that genre 'reaching its natural limits' and there being 'few rappers who don't actually want to sing'. This may be true, in some cases, but it's only a small part of the story, which goes back to the second half of the 1980s and starts with the musical phenomenon known as 'swingbeat'.

In swingbeat, a straight R&B- based, singer-and-band approach met rap's computerised studio techniques. Names to mention at the time were the writing and production team of LA & Babyface (responsible for records by The Whispers, Karyn White, Whitney Houston and The Jacksons) and the teenage whizz-kid Teddy Riley (Keith Sweat, Kool Moe Dee, his own group Guy). But it wasn't until both these camps assisted with Bobby Brown's Don't Be Cruel album in 1988 that swingbeat became a serious mainstream proposition.

Even with an eight-digit sales total, the LP was more important for its projected personality and content. At the time, there was a generation of teenagers who couldn't remember life before rap, yet as performers became increasingly extreme in their political attitudes and their aggression, the distance between them and younger record buyers (the industry bedrock) widened. Only the rappers LL Cool J and Will 'Fresh Prince' Smith appeared to court pin-up status in the old-fashioned style. Meanwhile the established soul crooners (Luther Vandross, Alexander O'Neal and Barry White) were, at their time of life, somewhat unappealing to the average 14 year old. The marketing gap was there, and Bobby Brown was almost over-qualified to fill it.

Then only 19, he understood his audience perfectly; for five years he'd been part of bubblegum soul sensations New Edition who were conceived as a Jackson 5 for the 1980s; he was undeniably good-looking; and his musical interests combined soul and hip hop. Don't Be Cruel went further than just spot-welding some computerised rhythm tracks to the traditional soul production. Brown added rap's essential arrogance to his own blend of showbiz suave. He would seamlessly slip from singing (complete with harmonies) to rapping, mid-number.

It signalled to young black Americans that you could be tough and sing sweetly, and it would probably go down well with the girls. While the music became sparer and harder- edged, the vocals became smoother, subtler and more far more intricate. In this modified form, the music started calling itself New Jack Swing, and at its core were Brown's former New Edition colleagues: Johnny Gill and Ralph Trevsant both launched giant solo careers; Michael Bivins, Ronald DeVoe and Ricky Bell were voted Billboard's 'Best New Group' as Bell Biv Devoe. And Bivins formed his own production and management company to have instant success with ABC, a five-piece vocal group with an average age of nine, and Boyz II Men, four church-trained teens who sing a cappella and then add beat-box backing tracks.

The upsurge in Afro-American film has accelerated the boom. Film-makers found the music afforded street credibility without alienating the mainstream. The a cappella group Take Six have maintained a high profile since contributing to the Do The Right Thing soundtrack. (It was on the Spike Lee-written and directed BBC TV documentary Do It Acapella, incidentally, that Tom Jones first spotted True Image.) New Jack City's soundtrack was the most talked about aspect of the film; and, after it had become an oft-used requiem at ghetto youths' funerals in real life, Boyz II Men's unaccompanied 'It's So Hard To Say Goodbye To Yesterday' was played at a screen gang member's last rites during Lethal Weapon 3.

Brisley says, 'There'll never be a shortage of newcomers because so many learned to sing like that at church as a natural part of growing up. Quite apart from good singing, presented properly, always appealing, it's because so many of the style's record buyers remember singing in church that they're going for it in such a big way.'

A lack of strong church singing traditions in Britain contributes to the style's slow progress in this country. Also, the music isn't quite hard enough for UK hip hop fans with an acute taste for acts like Public Enemy, NWA and Ice Cube. It's not unlike the UK reggae market of the Seventies, when it was the heavier dub tracks that were in demand, while the softer 'lovers' rock' sold little outside the UK's inner cities.

This looks unlikely to change in the near future, although Bobby Brown is about to release his first new album for three years. He is the only artist of this type to make anything like a lasting impression in the UK. Advance tapes show his approach has in no way mellowed; the album's production is at the cutting edge of the style, and once again uses Teddy Riley as a co- producer. Riley was drafted in to weave his magic on Michael Jackson's Dangerous album, a record that, over here (and in spite of Jackson's highly publicised tour) is being outsold two to one by Simply Red's Stars.

(Photograph omitted)