London Jazz Festival, various venues

The Friday launch of the London Jazz Festival routinely runs a grand-slam singers showcase, Jazz Voice, at The Barbican into a late-night taster menu at Ronnie Scott’s. The first presents jazz at its most accessible while the second rounds up the fierce and the funky.

This year’s Jazz Voice opened with a highlight, Gregory Porter singing Nina Simone’s “Feelin’ Good”. Unaccompanied, and in the spotlight, Porter walked through the audience investing each syllable with joy and hope. It set a high benchmark.

Jazz Voice prides itself on the breadth of its vocal stylists; this year’s included Americana from Lucinda Bell, svelte precision from Norma Winstone and Ian Shaw, and belting soul from Mary Pearce. Continuity was kept by the bish-bash brass and lush strings of Guy Barker’s arrangements for the 42-piece orchestra and the largely songbook repertoire – soul covers, as well as a medley celebrating the Impulse record label were delivered in the house style.

In a night when clear articulation and accurate pitch were givens, those who got inside the lyrics and sold their songs stood out most. Ayanna was the full torch-song package on “Love for Sale” and put her own understated stamp on “Strange Fruit”; the Noisettes’ Shingai Shoniwa pulled off a coup with a telephone on “Love Me or Leave Me”, and a beguiling Michelle Dockery – yes, of Downton Abbey – showed elegant poise on “Sans Souci”.

Gregory Porter’s blend of high-end soul and vocal jazz tradition remained the highlight, his musicality and narrative drive confirmed on the self-penned description of a riot “1960 What”. Porter, the last of four acts presented at Ronnie Scott’s, later revelled in the extra space afforded by a piano trio, and on Wayne Shorter’s “Black Nile”, showed a rare gift for jazz-vocal improvisation.

The show opened with Oren Marshall blowing away the comfort zone with free and screechy solo tuba, but his main spot featured gentler African-inflected vibes. The well-named Charming Transport Band featured lazy-rhythmed alto dancing across somnolent tuba and a cushion of percussion.

Grit came from the third act, Guillaume Perret & The Electric Epic. Perret veers from soft-centred soul to full-on distortion and seemed quite quaint after the acerbic saxophonist Steve Coleman and his Reflex trio. Coleman’s lines, spun from two repeated notes, embodied the spectral structures of pure thought. But he delivers his icy intellect with such a warm tone that he enchanted as well as intrigued.

Saturday’s Barbican double bill celebrated the 50th anniversary of the Impulse label by re-imagining two classic albums, Oliver Nelson’s The Blues and the Abstract Truth and John Coltrane with Johnny Hartman. The first investigated the subtleties and breadth of the blues form, and was recreated by a septet led by James Pearson. The haunting pleasures and jagged edges of “Stolen Moments”, “Hoe Down” and “Teenies Blues” came to life, with saxophonist Nathaniel Facey managing an authentic Eric Dolphy squawk.

The second album is an iconic, ballad-heavy oddity – it was John Coltrane’s only recording with a vocalist. It was here re-conceived by McCoy Tyner, the original pianist, as a downbeat interlude in a rip-roaring set. Guest vocalist Jose James had the low range and dignified precision of the original, but it was a vigorous McCoy Tyner who dominated. Full left-hand chords pounded the lower register, meditational ripples flowed in the treble and there were moments of unaccompanied tranquillity. And with saxophonist Chris Potter going for broke, the ovation was intense and prolonged.

London Jazz Festival runs until November 20; www.londonjazzfestival.org.uk