| Have you ever wondered how you hear different | | | | exact replica of an orchestra instead of a one |
| sounds coming out of your left and right speakers | | | | man band. Another approach to this technology is |
| and not the same sound on both? This dual sound | | | | called the MS or Middle-Side Technique. This |
| is called stereo sound. Stereo sound is produced | | | | technique involves one element to be bi-directional |
| by stereo microphone recordings from a studio or | | | | and the other omni-directional. The bi-directional |
| concert setting. To give you a better | | | | records all sound except for the center area and |
| understanding on this works here's an explanation | | | | the omni records everything. This results in sound |
| of a mono-microphone. Microphones work by | | | | first moving through the bi-directional component |
| intaking sound waves which vibrate a diaphragm | | | | and then through the omni component giving you |
| connected to an amplifier circuit. | | | | the feeling of which direction the sound is coming |
| The diaphragm is typically made out of a material | | | | from. If the sound comes from either side the |
| called electret, which is a type of plastic. The | | | | signal is louder than any instrument that makes |
| electret has a maintained charge on it which | | | | noise from the center. |
| allows electricity to flow. The disadvantage to | | | | The sound differences are separated into |
| using this plastic material is that it only holds a | | | | channels to maintain the sound difference of the |
| charge for a couple years before it has to be | | | | two sides and are played back on right and left |
| replaced. | | | | speakers. Imagine listening to a band that sounds |
| As the diaphragm moves the sound waves are | | | | like the noise only comes from one person and |
| converted into an electrical signal through the | | | | not all members of the band. The sound you hear |
| amplifier, called rarefactions and compressions. | | | | would not have enough fluctuations in sound |
| The signals from the amplifier are then recorded | | | | waves for your ears to hear the audio levels |
| onto a medium like a tape, cd, or record. So, in | | | | each instrument and vocal are actually producing. |
| order to make a stereo microphone, two | | | | The performance would be just like karaoke |
| microphones are encased, put at a 45 degree | | | | instead of professional. This is why stereo |
| angle, but have to be bi-directional. This placement | | | | microphones are needed to produce optimal |
| is also referred to as X-Y setup or Blumlein Pair. | | | | sound performance. |
| Due to this configuration the sound is like and | | | | |