The Swedish Rauna company, which has been in existence for about five yearstheir little Mk.II Tyr two-way impressed J. Gordon Holt a couple of years back in Vol.9 No.2appears to be dedicated to the use of concrete as an enclosure material. One of the problems with conventional wooden cabinets is that the walls flex and vibrate, adding a spurious and often time-delayed output at some frequencies. It has even been reported that in extreme cases, the contribution of the cabinet to the overall sound at some frequencies approaches that from the drive-units. In theory, concrete should give a rigid construction with any panel resonant frequencies moved up above the critical midrange.