No. 3: Horn Array Speakers (Japan)
Horn Array Speaker Features
Showing their mettle in times of emergency
An innovative new direction in public address, horn array speakers deliver clear emergency broadcasts even to distant locations
The Great East Japan Earthquake unleashed unprecedented destruction in the affected regions. One difficulty that came to light during that terrible event was that in certain areas it was difficult to hear the wireless emergency evacuation broadcasts intended to alert residents about the incoming tsunami. Anticipating further disasters that might come in the near future, what can be done now to help save more lives? Part of the answer lies in TOA's newly developed "Horn Array Speakers," which offer an effective sound delivery range several times that of conventional speakers.
A horn array speaker is a new type of public address speaker comprised of several square horn speakers connected together into a single unit. These multiple speakers all broadcast the same sound simultaneously, and in the process of being transmitted these sounds can be controlled to overlap in a way that increases their energy, resulting in sound that can be heard clearly at distances up to two or three times that of conventional speakers. Further, their vertical directivity can be narrowed easily, effectively suppressing the loudness of the sound in the immediate vicinity beneath the speaker location so that it doesn't bother those in directly adjacent neighborhoods.
The difficulty in hearing evacuation instruction broadcasts during the recent earthquake had various causes in different regions. In some cases there were simply not enough speakers, and in others the speakers that were used did not have a far enough range and couldn't cover the whole area. Sometimes multiple speakers broadcasting at the same time interfered with one another and created an echo-like "round" effect that made the content difficult to understand.
Horn array speakers could be used more effectively in such circumstances. Their long range can allow them to cover a wider area with fewer speakers, and their lack of interference can reduce the round effect, solving both problems at once.
A further advantage of horn array speakers is that their relatively fewer installation locations compared to conventional speakers means easier maintenance and upkeep.
Horn array speakers are already in operation at regional municipal facilities in Hiroshima, Okinawa, and Kanagawa prefectures, as well as in Pacific coast regions like earthquake-prone Shizuoka prefecture, and in regions now recovering from the Great East Japan Earthquake. Requests for sound transmission tests have been pouring in, and the TOA staff has been accommodating these by travelling all over Japan with its demonstration speakers and measuring instruments.