Assertion: speaker's amplifier | /r/HasProperty | external
Facets:
Source sentences:
text: What could be seen as a pro for some and a con for others, the Q Acoustics Concept 20 speakers are passive and require an external amplifier.
text: Most such speakers have an internal amplifier and consequently require a power source, which may be by a mains power supply often via an AC adapter, batteries, or a USB port.