Ultrasonic speaker or ??

Yea I know that it sounds high. I think they are using an ac adapter and using the voltage swings for inflated wattage figures?? plus using multiple piezo transducers to multiply the wattage figure.
This piezo stuff is driving me to drink!

MrDEB said:

Yea I know that it sounds high. I think they are using an ac adapter and using the voltage swings for inflated wattage figures?? plus using multiple piezo transducers to multiply the wattage figure.
This piezo stuff is driving me to drink!

Click to expand...

No, it's not claiming to provide 400W, and DC input is only 24W according to the final output diagram.

The audio 'power' is supposed to be the 'equivalent' of 400W due to the high efficiency of the piezo transducers compared to conventional transducers.

However, that device seems to do pretty well exactly what you're looking for?.

I don't know how they calculated 400 Whats!
The circuit has an output stepup transformer. The article says 20V p-p and also says 15V RMS. 15V RMS produces 28 Watts into 8 ohms but since the output is a square-wave then the fundamental is only 14 Watts.

The article claims that the four piezo tweeters produce 120dB at 18 inches. Then at 3 feet the sound level is 114dB and at 48 feet the sound is 90dB which is pretty loud.

They calculated using a home mortgage calculator w/ adj rate of wattage. LOL
And to verify their results they used a wall street banker