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ok guys, help me out here....my little sister in law is doing a presentation on this at school. i think i know what they are, but seeing as how my stereo knowledge is not book taught, i don't know the terms.... she's going to take a home stereo to school, and show how when the speakers are facing each other closely, they have cancelation. then she's going to put them at a 90 degree angle to each other and show how the waves combine to have a louder output. do you think this would be an effective way to get these concepts across to junior high school kids? she lives halfway across the country from me, so i can't just build boxes to demonstrate this. would a ported enclosure have the effect of a constructive wave? please just give me some input on this.....thanks
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Posts: 2177 | From: Stanton, MO | Registered: May 1999
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posted
To start - constructive waves combine to produce a result larger (greater intensity) than the individual waves. Destructive waves combine to produce a result smaller thatn the individual waves.
This would be most apparent with bass in her demonstration. For construdtive interference she could have the two speakers playing bass far apart and then move them close together. When they are side by side the overall bass level should be louder. This may not be readily apparent in a large room. For destructive interference, simply repeat the test but with the polarity reversed on one of the speakers. WIth them far apart (something over 10feet or so) they should sound just like normal but when brought close together the bass should drastically diminish.
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transfer the waves to water wave you can see. people believe and understand what they can see best. Hearing does do that as well.drop marbles into water at two spots and watch the waves cancel out and out strangely in the center
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Posts: 1147 | From: Rowlett, TX, USA | Registered: Jun 2000
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