Matthew E White is explaining the power of musical arrangement. It’s what he does best with his production house, Spacebomb, which will be showing off its achievements to date in a one-off concert this evening at the Barbican. A “Revue” event will be put on featuring strings, choir, the Spacebomb house band and the vocals of artists who have graced their studio, including Natalie Prass, Mike Scott of The Waterboys, Bedouine, Charlie Fink from Noah and the Whale, and White himself.