No apologies for having two of WAO138?!’s number amongst our review flock this month. Their current form really is that rich. In a singularly positive fashion, Signum have always made great stock from positioning themselves in the genre’s artistic middle ground. Getting the best of all worlds, 'Knock Knock' typifies this stance. Shifting with supreme fluidity between sound-styles, and bound together by Ron Hagen’s apparently effortless production engine, this release delivers thrills from first minute through last.