Both the volume and duration are measures, which are strings of the format "value:unit". FYI, ISO 31-0 [0] already defines a single space as the separator betw

Both the volume and duration are measures, which are strings of the format "value:unit". FYI, ISO 31-0 [0] already defines a single space as the separator between the value and the unit. Granted, most people (and even some scientists) don't know about this rule. [0] http://en.wikipedia.org/wiki/ISO_31-0#Expressions http://en.wikipedia.org/wiki/ISO_31-0#Expressions