Q. What does the "program" part of the "Power Handling (program)" specification mean?
Answer:
As an example, if the speakers are rated 15-60W, if you play music with a 60W amp flat out (as long as it is not clipping) the speaker in question will handle it, but if you put a continuous sine wave at 60W through them, they wouldn’t. The speakers will be perfectly happy connected to a 100W amp, as long as it is used sensibly (as it is within the capability of the amp to damage the speakers). But this is true even of a 50W amp if you put a continuous clipped signal in, as the heating effect would be that of a much larger sine wave. Maximum continuous power handling can be a difficult number to pin down, which is why a real world program figure is given, and as a
general rule, it's better for a loudspeaker to be driven by a high powered
amplifier used responsibly, rather than a low powered amplifier
over-driven.