Assertion: speaker's amplifier | /r/HasProperty | powered by battery
Facets:
Source sentences:
text: Second, in order for the speaker to take the electrical sound impulses and convert those impulses into an actual sound that you can hear, the speaker needs to be physically connected to an amplifier, which can be powered either by a battery (most applicable for portable devices) or AC power.
text: The amplifier may be built right into the speaker housing or, in some cases, the speakers are physically attached with speaker wire to an external amplifier that is powered by batteries or plugged into an AC power source.