Ключевые слова: ad, advertisement, advertising, amplifier, announce, announcement, area, attention, audio, blue background, broadcasting, bullhorn, business, communication, content, demonstration, device, discount, electronic, equipment, freespace, gesture, hand, isolated, loud, loudspeaker, management, megaphone, message, mock up, object, pastel, place, political, portable, proclaim, promotional, protester, public, refer, sale, scream, shout, sound, speaker, technology, volume, workspace, yellow,