fadY
New Member
Hi,
I am working on a project called "parametric array". It's a device that makes sound to be very directional. If you want to learn more about it you can visit the site: **broken link removed**
Actually to have the directionality effect, you have to mix an ultrasound signal to the audible sound you want to transmit. I realized an Amplitude Modulation circuit using as a carrier a 38kHz sine wave and as a signal 1kHz sine wave.
My college had the ultrasonic emiter given by ATC for a demo. So I just had to match the emiter to an amplifier. I have been told by ATC that my emiter had a 160nF capacitance and a 2 Ohm resistance. I built a 8W amplifier and plugged an inductor of 150µH in series with my transmitter to compensate the capacitance of the emiter.
That went good, I had quite a low volume but I could hear that the device produced very directionnal sound.
I am now trying to plug it on an audio 50W amplifier. I firstly checked that my amplifier (Rotel RA931MkII) worked good at frequencies as high as 60kHz (pluggin it on a 4Ohm resistor and studying voltage vs. frequency). That was ok.
Then I tryied it on my emiter.To be more cautious, I plugged a 4Ohm resistance in series with the inductor and the emiter. But, when I tried to make it work, the voltage at the output of the amplifier didn't go above 1V (with 1V input) and the amplifier began to spread roasted components smell :roll: so I turned it off...
Do you know something that could help me in understanding my problem?
Thanx
fadY
I am working on a project called "parametric array". It's a device that makes sound to be very directional. If you want to learn more about it you can visit the site: **broken link removed**
Actually to have the directionality effect, you have to mix an ultrasound signal to the audible sound you want to transmit. I realized an Amplitude Modulation circuit using as a carrier a 38kHz sine wave and as a signal 1kHz sine wave.
My college had the ultrasonic emiter given by ATC for a demo. So I just had to match the emiter to an amplifier. I have been told by ATC that my emiter had a 160nF capacitance and a 2 Ohm resistance. I built a 8W amplifier and plugged an inductor of 150µH in series with my transmitter to compensate the capacitance of the emiter.
That went good, I had quite a low volume but I could hear that the device produced very directionnal sound.
I am now trying to plug it on an audio 50W amplifier. I firstly checked that my amplifier (Rotel RA931MkII) worked good at frequencies as high as 60kHz (pluggin it on a 4Ohm resistor and studying voltage vs. frequency). That was ok.
Then I tryied it on my emiter.To be more cautious, I plugged a 4Ohm resistance in series with the inductor and the emiter. But, when I tried to make it work, the voltage at the output of the amplifier didn't go above 1V (with 1V input) and the amplifier began to spread roasted components smell :roll: so I turned it off...
Do you know something that could help me in understanding my problem?
Thanx
fadY