====== Interference With Two Sound Sources ======

{{tag> oscillations_and_waves speakers interference acoustics located}}

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{{Two_Speaker_Interference.jpg?400|}}

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===== Description =====

Consists of a pair of speakers hooked up to the amplifier and a function generator.


===== Purpose =====

To demonstrate the interference pattern produced by two sound sources.  

===== Apparatus =====

  * [[demonstrations:3_oscillations_and_waves:sound_waves:speakers:start|A pair of speakers]]
  * [[demonstrations:9_equipment:oscilliscopes_and_function_generators:function_generator:start|Function generator]]
  * [[demonstrations:9_equipment:av_receiver_amplifier:start|Amplifier]]

===== Setup =====

  - Place the speakers on a cart at least two feet apart. You will have to adjust this distance according to your frequency
  - Attach the function generator output to the Amplifier and connect the amplified outputs from the amplifier to the input at the back of the stereo labeled "Phono Right"
  - Ensure the stereo is set to play the phono input 
  - Attach the two cables from the back of the stereo to the speakers as shown in the picture
  - Test the speakers to check if the polarity is right (they only work one way) 
  - Select a frequency on the function generator and turn up the volume on the stereo 
  - The table (or cart) can be turned so that any interference pattern produced in the direction of the speakers can be swept across the audience producing audible maxima and minima

===== Notes =====

In the new Hebb theater (as of 2020), a frequency of 600 Hz with three feet of separation between the speakers seems to show a noticeable effect.

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<WRAP box>
<WRAP centeralign> // Demo room information // 
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<WRAP tablewidth 100%>
| **Location** | T1 |
| **Maker** | Unknown |
| **Current State** | Working |
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