The Sealed Knot are one of the great free improvisation groups, comparable to the classic 1980s SME line-up of John Stevens, Nigel Coombes and Roger Smith for edge-of-your-seat attentiveness and sheer inter-group telepathy. Rhodri Davies, Mark Wastell and Burkhard Beins have been a unit since 2000, a melding of London and Berlin. Recent sightings have been rare, but they played in Berlin this May, and now Wastell’s revived Confront label is releasing this live album from January 2009.The purpose of the 2009 show was to celebrate Another Timbre’s release of And We Disappear, recorded live in Switzerland at a 2007 festival titled Ear We Are. That album was about the yawning gulf between Davies’s high, piercing ebow work and Wastell’s glacial double bass. Whereas the new record has Wastell switching to tam tam, and all three musicians employing electronics – but lo-fi mechanical electronics, rather than digital processing. So there’s a pleasing, subdued industrial fury lurking beneath the music. Filigrees of rapid clicking make way for subterranean pulsing, and Beins adds the super-pure tones of bowed cymbals, to blur the electric/acoustic distinction further. Around 18 minutes the group contemplate silence, before launching into a further 13 minutes of patient exploration and metallic mystery.Wastell has grumbled that critics are “always 12 months behind the flow” when it comes to describing what musicians are up to, and here he is, helping us along by releasing a four year old recording. Never mind that the trend-buzz around Lower Case Improv, New London Silence & co has worn off; with music of this quality we’re dealing with simple excellence, and any opportunity to see this group at work should be seized.