SPEAKERS AND SOUND

1. SPEAKERS AND SOUND Nathan Grisier Emmanuel Villarruel PrajaKatel Jackson Lund

2. What you’ll learn • Sound Interference and Overtones • Amplifiers/Speakers • Acoustic Architecture • Line arrays

3. Sound Interference and Overtones • Sound • Produced from vibrations • Loud enough for everyone to hear • Interference • Weather • Destructive interference • Opposite vibrations

4. Overtones • Other frequencies besides the fundamental that exist in musical instruments • Different musical instruments produce different overtones • Create individual sound of instruments • Most instruments would sound the same if it weren't for overtones

5. Instruments

6. Amplifiers/Speakers • An electronic amplifier that amplifies low-power audio signals to a level suitable for driving loud speakers is the final stage a typical audio playback chain

7. The History of Modern speakers • Lee de Forest • Invented the first audio amplifier, 1909 • Triode Vacuum tube • AM radio • MattiOtala • Discovered Transient Intermodulation Distortion (TIM)

8. How sound is amplified • Sound waves are perceived by the microphone and are then converted into corresponding electrical voltage varying in frequency and amplitude according to pressure of the sound vibrations • Many amplifiers have provision for receiving the signals from several microphones or other sources , combining them, and amplifying the combined program to the power required for the audience to hear easily

9. History of Acoustic Architecture and design • Roman Era • Vitruvius • Wrote “De Architectura”, known today as “The Ten Books on Architecture”. • Beginning of acoustic architecture • Renaissance • Opera houses • Concert halls • Churches • 18th Century • Experimentation • 20th Century • Wallace Sabin

10. Noise Control • A = Absorb • Reduces reverberation • Porous absorbing materials • drapes, carpets, ceiling tiles, etc. • B = Block • Prevents sound waves from continuing on their path • panels, walls, floors, ceilings and noise barriers. • C = Cover-up • sound masking • white or pink noise

11. Outdoor Noise Control • Regulating sound levels • To much noise can be a health hazard, so rules have been set in place that engineers have to be aware of when building a venue • Noise barriers • Walls that are placed around the venue to try and prevent the sound from escaping to residential areas • Buffer zones • Place commercial/industrial buildings around the venue rather than residential.

12. Line Arrays • Why and what are line arrays? • Line arrays are a group of speakers, usually 3- 12 or as much as 20, stacked on top of each other and hung at a diagonal angle. • Time delay • Sound is a directional waveform and travels around 1000 ft/sec. causing time the time delay to differentiate between the front row to the middle to the very back row of the venue or concert field. • The job of the sound engineer or technician is to balance

15. Solving the problem • In order to reach the everyone line arrays are strategically placed on the stage and throughout the audience. • The sound output to the middle row line arrays are put on a time delay • In order to find the right time delay, measure 1 milsec/ft from the middle row

16. Conclusion • next time one of you attend a concert, whether inside or outside, you will be able to understand why the speakers and the music sounds clear and full of life

17. THE END