I've used that CD from a portable CD player and later an Ipod. It works fine. > On Jul 22, 2014, at 8:49 PM, "Ira Wilner" <bdcst at vermontel.net> wrote: > > I no longer own a continuously > variable audio generator, sigh! But I do have a copy of the 1988 NAB > Broadcast and Audio System Test CD. Bessel calibration tones are on tracks