Ключевые слова: alert, amplifier, announce, announcement, attention, audio, background, blue, broadcast, broadcasting, building, bullhorn, business, communicate, communication, concept, electric, electronic, hand, horn, information, isolated, loud, loudspeaker, megaphone, message, microphone, object, old, outdoor, pole, power, public, retro, shout, sky, sound, speak, speaker, symbol, system, talk, technology, top, vintage, voice, volume, wall, warning, white,