The cast and band are in the thick of rehearsals for The Beautiful Cosmos Of Ivor Cutler, Vanishing Point theatre company's impressionistic music homage to the Glasgow-born poet, singer and stalwart of the late John Peel's radio programme, which speaks volumes.
Cutler was, after all, a member of the Noise Abatement Society, and claimed to loathe amplified music in all forms. The feedback is a consequence of a late-running sound-check caused by a piano's exterior splintering in a way that rendered it unusable. A replacement piano found at short notice, a piano tuner was also required to before work could proceed.
The band is led by musical director James Fortune, and includes multi-instrumentalist and recipient of a Herald Little Devil award Nick Pynn. Pynn, who has worked with comedians Stewart Lee and Boothby Graffoe, won the award with his partner, Kate Daisy Grant, after the pair got married on their only day off from their Edinburgh Festival Fringe show. With keyboardist and vocalist Jo Apps, guitarist Ed Gaughan and percussionist Magnus Mehta also on board, Fortune has pulled together a dynamic and eclectic ensemble.
"For me," says Fortune, "the challenges are to investigate the songs enough so you can rework them, but still keep their original spirit intact. A lot of Ivor Cutler's songs sound like they could have been sung by Paul Robeson. There is cowboy music in there, and there is something Jewish there as well."
As well as the piano, the stage is awash with other musical instruments, with a couple of old-fashioned armchairs nestled in front of the piano in a way that suggests the Scotch sitting room immortalised in Cutler's brutally absurd stories. Elicia Daly, who plays a version of Cutler's partner, Phyllis King, sits obliviously knitting on one of the chairs. Leaning up against the piano are a series of oversize reproductions of the sleeves for each of Cutler's albums.
At the front of the stage, set apart from everything else, sits a harmonium. In its isolated state, this wooden monster of an instrument looks like a miniature altar. The fact the harmonium once belonged to Cutler makes the presence of the man interviewers were instructed must be called Mr Cutler even more tangible.
The instrument was re-discovered by musician and Celtic Connections director Donald Shaw. It had lain in storage for years after Cutler had apparently abandoned it following a show in Glasgow, where he was overheard in the wings giving the instrument a stiff talking to. Shaw bought it, and has now lent it to Vanishing Point. While this anecdote in itself could form the basis of a Cutler tribute, it is a long way from how Lenton originally envisaged the show.
"It's a biography, a celebration and a gig," he says of how it has turned out. "What we did not want was to just have someone imitating Ivor Cutler and what he did. You can get the real thing on YouTube, so there is no point on that. We wanted to do something that told a story, but which said something about Ivor Cutler's life.
"I have always said it's an anti-Mamma Mia! When you look at Mamma Mia! it is the work of Abba structured together, but Abba do not play a part in that musical, so anyone could have written those songs. That was my first idea with this, to make it something completely separate from Ivor Cutler's life, but the more work we did on it, the more we found you can't separate Cutler's work from his life."
Rather than make a Vanishing Point approximation of a jukebox musical, Lenton, along with Fortune and actor and company associate Sandy Grierson, have done something more akin to the rock and roll biographical shows Elvis and Buddy. This has been done using a mountain of research material pulled together by Grierson, and enabled with the help of Cutler's son and King, who have allowed Vanishing Point unlimited access to their archives. Despite such exhaustive researches, Lenton is not aiming to creative something rarefied.
"It has got to be a story that people who don't know anything about Ivor Cutler can come along," he maintains, "as well as one that aficionados can enjoy. On one level it is quite a simple story, although it is never a naturalistic portrayal of Ivor Cutler. It is a biography told through his songs, and it is a celebration, but it is not just fragments. There is an aesthetic to Cutler, and there is something really Russian in his radio plays, and that is the essence we want to capture."
With the piano tuned, the band warm up as Grierson walks the stage with a giant cut-out of a vivid green sea creature. Costume designer Jessica Brettle comes in carrying two tweedy tartan caps that would not look out of place on a well-dressed Womble. They are, of course, dead ringers for Cutler's own head-wear, and Grierson dutifully tries them on for size.
The band run through a version of Cutler's late song, A Bubble Or Two, which, by way of an alternating male/female vocal and a twanging guitar, becomes transformed into the sort of galloping wild west melodrama on which Lee Hazlewood might have duetted with Nancy Sinatra.
It is louder than Cutler's original, but there is a reinvigorated joy there that even a member of the Noise Abatement Society might tap a toe to. "I think he would be all right with that," says Fortune, "but you have to be careful to get the balance right."
The Beautiful Cosmos Of Ivor Cutler, Citizens Theatre, Glasgow, April 9-20, then tours.