This may be the ambigious project.
I want to make my room completed with the Audio Cancelation circuit. The aim is to keep the room quit from the sound or noise from outside room (from door or windows). The idea is to put the microphone to sense the audio (noise), and then use the Microcontroller or DSP to make the opposite wave that cancel the audio or noise.
I think the circuit & firmware implementation is not that simple. do you?
Anyone have the idea or experience about this?
Please share.
Event the room is not so big (2x3)m, or inside the car (the noise from engine)?
The sound (noise) could be music frm other room, or the noisy engine in the car.
Some japanese car have this equipment.
How about using the microphone (loacted near the door / window)to catch the sound (noise), then use the DSP or microcontroller to generate the out of phase waveform (refer to the sinyal of the microphone).
Then use the second microphone (located in the room) as the feedback to fine adjust the phase and the amplitude, so needed the closd loop control.
Do you think this idea can be implemented?
Please give some comment or advise.
First of all, audio cancellation can be done for certain noise sources. There is a useful article on thin in one of the back-issues of "Analogue Dialog" from Analog Devices (year 2000, if I remember correctly).
I agree with you about the phase differences, but if we can cancel the wave near the source (on the window, door, etc), so there is no wave can be propagate through the room. What do you think?