German reference speakers – that's what Gruensch believe they have in their Grand Reference. Considered an open baffle with integral guides to create a "naturally diffuse sound field", the upper driver array centres on a planar 8" widebander covering in excess of four octaves up to 15kHz above which a ribbon super tweeter takes over. Two 10" planars bracket the widebander to be themselves bracketed by 8.5" woofers. The 15" active sub-bass driver meanwhile loads into a sealed enclosure. Crossovers are 1st order. Bandwidth is 15Hz – 100'000Hz, sensitivity 91dB and nominal impedance 7.1 ohms. Each speakers weighs 200kg and measures 155.5 x 34.7 x 65cm HxWxD.