HIFI ultrasonic directive(parametric) speaker kit(assembled)10mmx48pcs

Description

This is ultrasonic directive speaker kit.
already assembled
HIFI type( high quality like FM radio)
You can experiment directive sound beam.
sound reach about
10m
in silent room.
Double than before
This kit is based on article of Elector magazine in March 2011.
Please read this article for details of kit.
48pcs 10mm,ultrasonic transducers(color may be black)
PWM driver PCB
DC power jack is most popular 5.5mm(internal 2.1mm) type using laptop.
about 15V to 24V(upto 35V) center pin is +(plus) if 35V, you need larger heat sink.
audio input 3.5mm phone jack. you need external amp about 1W to 2W.
read more details.
D class driver and transducers
From the principle that sound comes out, the bass range is not strong.
youtube demo(search "nondirectional speaker")
This kit produce strong pulse. radio, smartphone are effected by ECM noise.
There is distortion from principle of ultrasound.
You can not use microphone directly as loud speaker.
This kit does not including microphone amp.
All kits are shipped after confirming that they work properly.