The Wharfedale MACH 9) Some competing loudspeakers sold at the time were the Bose 901 Series IV and V, Bose 201 Series I, Bose Series 601 Series II, JBL Delta, Cerwin Vega D series, JBL Radiance, JBL Sigma, and Acoustic Research AR-58B. The Wharfedale MACH The Wharfedale MACH series of loudspeakers consists of the MACH 3, 5, 7, and 9. This is an informational page devoted to owners and users of these loudspeakers and those interested in history and construction of electronic sound reproduction. These loudspeakers were manufactured at Rank Hi-Fi, Wharfedale Works in West Yorkshire by Wharfedale Loudspeakers in England (UK). They
Mach number speeds, it is a dimensionless number. If < 0.2–0.3 and the flow is quasi-steady and isothermal, compressibility effects will be small and simplified incompressible flow equations can be used. The Mach number is named after Austrian physicist and philosopher Ernst Mach, and is a designation proposed by aeronautical engineer Jakob Ackeret. As the Mach number is a dimensionless quantity rather than a unit of measure, with Mach, the number comes "after" the unit; the second Mach number is "Mach2" instead of "2Mach" (or Machs). This is somewhat reminiscent of the early modern ocean sounding unit "mark" (a synonym for fathom),