How can I create an active noise control stereo using simple terms?

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I want to create an active noise stereo which works like the headphones except it's a big speaker. I need your help on how i would go about doing this? I ain't no electrical engineer or anything, in fact I have no knowledge whatsoever so try to help me using simple terms.
 
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T.O.E Dream said:
I want to create an active noise stereo which works like the headphones except it's a big speaker. I need your help on how i would go about doing this? I ain't no electrical engineer or anything, in fact I have no knowledge whatsoever so try to help me using simple terms.

Have you been through the intro page at wikipedia, and followed some of the links at the end of the article?

http://en.wikipedia.org/wiki/Active_noise_cancellation

.
 
A question about active noise control. Does there need to be a specific angle at which the speakers must be at with the sound source?
 
T.O.E Dream said:
A question about active noise control. Does there need to be a specific angle at which the speakers must be at with the sound source?

Yes, I believe that placement of both the noise source, the noise cancelling speaker(s) and the listener(s) are important. Can you tell us why that would be? BTW, do you know the speed of sound in air? And what is the normal range of frequencies of audio sounds that we hear? What are the corresponding wavelengths of sound in air? (Quiz questions for you)
 
im a musician who is also studying physics at high school, and we have come to the part where we talk about how speakers work and so on, but what i asked and my teacher couldn't sanswer was, how does a speaker produce the different tone colours of instruments.
if a violin plays a concert C and then a trumpet plays a concert C, how does the speaker change the tone of the sound so we recognise it as the respective instrument??
 
A good quality speaker will just reproduce the waveform that comes from the instrument.

Because the waveforms are different from each other, our ears recognise the instrument by its different waveform.

This is the waveform of a saxaphone:
http://hyperphysics.phy-astr.gsu.edu/HBASE/Music/saxw.html#c3
Oscilloscope-style waveform plot over 0 to 15 ms with a voltage axis from -1.29 to 1.29, with an FFT bar chart below showing the harmonic spectrum, where harmonic 2 dominates at 1.00 and harmonic 1 is about 0.52.


This is the waveform of a clarinet
http://hyperphysics.phy-astr.gsu.edu/hbase/Music/clarw.html
Top: a periodic waveform trace over 0 to 16 milliseconds, with vertical axis labels 1.51, .757, 0, -.757, -1.51. Bottom: bar chart of Fourier transform harmonic amplitudes for harmonics 1 to 15, with the fundamental and third harmonic tallest. Right: table of harmonic amplitudes.


Note that the speaker cone can only be in one position at a time, so it only traces one waveform, even if it is reproducing all the instruments of the orchestra.
 
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  • Oscilloscope-style waveform plot over 0 to 15 ms with voltage from -1.29 to 1.29, above an FFT bar chart showing harmonic amplitudes; a table lists harmonics 1 to 10 with amplitudes .52, 1.00, .04, .04, .01 and .00 for the rest.
    saxw1.gif
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