this horn-shaped speaker produces high-quality sound without using power

the sound is made louder by using reverberation

designed by loudspeaker manufacturer noboru denki. ‘sound loudspeaker NMP-001’ is a non-powered passive speaker for commercial use. the brand has been a specialist manufacturer of loudspeaker audio equipment for commercial use for 75 years since its establishment. they created this device to allow users to enjoy high-quality sound without using any power source. all you have to do is insert your smartphone into the recess and blast your favorite music or radio sound.

the sound is made louder by using the reverberation of the three-layered ondo of the horn, so the user can enjoy it outdoors, in the garage, during daily cleaning and cooking, and in any place where the power supply is remote. music and radio sounds from smartphones are echoed by passing through the tube, reflex, and horn of the internal mechanism, and are amplified into a high-quality sound.

all images courtesy of noboru denki

a reflex-type horn speaker type with excellent sound pressure

the device by noboru denki has a simple function, a slightly rugged but textured design, and a restrained coloring. the horn part has a shape that follows the structure of a general commercial horn speaker, in which an aluminum round plate is turned into a conical shape by spinning. measurements are taken in an anechoic room for acoustic tests in an environment that is not affected by ambient noise or reverberation. the arithmetic mean value was calculated from the frequencies of four points using a single-frequency sine wave so that there would be no gap in amplification, and amplification performance of +10 decibels or more was achieved.

project info:

name: sound loudspeaker NMP-001

designer: noboru denki