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Sound Systems. Objectives. Discuss the basics of a sound system Understand implementations & various uses, for both live and recorded music. What is a sound system?. The basic function of a sound system is to reinforce the sound.
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Objectives • Discuss the basics of a sound system • Understand implementations & various uses, for both live and recorded music.
What is a sound system? • The basic function of a sound system is to reinforce the sound. • Whether it is a public speaker with one microphone or a live band in a concert hall, the function is the same • ....to reinforce the sound.
Basic Components • Input Device • Mixer/Amplifier • Output Device
The Mixer This is the control center The mixer receives the input from a microphone, a direct connection from an instrument, or pre-recorded audio. We process the signal for volume level and tone quality, and then it sent to the output – speakers, headphones, or another recording device.
A mixer can change the individual quality of a sound: what is called the timbre (tone color). • A mixer can combine multiple sounds together • A mixer can blend multiple sounds together
Amplifier • A device that changes the amplitude (overall volume) of a signal. • Amplitude = height of a sound wave • Without an amplifier, we can not hear sound. • Size range from mp3 players to multiple units used in concerts and studios • The opposite of an amplifier is an attenuator
Terms • How much an amplifier increases the original level is referred to as its gain. • As you increase the signal strength, electrical noise is inherent (you hear it as a hum or hiss).
Types of Mixers Powered Mixer –Amplifier is built in Unpowered Mixer – Separate amplifier required
Channels • Mixers are classified by how many CHANNELS – input sources – they can accept • Channels can either be configured for MONO or STEREO input • MONO – for a direct input from a microphone or instrument • STEREO – for a direct input from a stereo source (perhaps a prerecorded input) • Each channel appears in a CHANNEL STRIP.
Channel Strip References • Online Mixer • Buckle Mixing Board
The Input Sound – what we PERCEIVE as sound – is our ear picking up on small variances of pressure waves in the air. A microphone does exactly that – but converts the pressure waves into electrical signals.
Dynamic Microphone • Takes advantage of an electromagnet • When a magnet moves past a wire (or coil of wire), the magnet induces current to flow in the wire. • The diaphragm moves either a magnet or a coil when sound waves hit the diaphragm, and the movement creates a small current
Condenser Microphone • Similar to a capacitor (an electronic device that stores current – like a battery). • One plate of the capacitor moving in response to sound waves. • The movement changes the storage amount of the capacitor, and these changes are amplified to create a measurable signal. • Usually need a small battery or electrical current to run. This is typically called phantom power, and is usually rated at 48v. • http://www.youtube.com/watch?v=OMs_tuBEo2Q
http://www.youtube.com/watch?v=nPjUB-KQ3_Q • They all have some sort of diaphragm that collects the signal. • The differences are how they convert that signal to a sound wave. • Today: we use dynamic and condenser microphones. Most efficient in processing acoustical sound into electrical sound.
Other types of microphones • Parabolic mic • Shotgun mic • Lavaliermic • Wireless mic • Pressure Zone mic • Kick Drum mic • Omnidirectionalmic • CardioidMic • Bi-Directional mic • http://www.youtube.com/watch?v=_MMHi8bQVv0
Speakers • In a perfect world – the 100% opposite of a microphone • What basic components do you think there are in a speaker?
Speakers 101 • The cone, usually made of paper, plastic or metal, is attached on the wide end to the suspension. • The suspension, or surround, is a rim of flexible material that allows the cone to move, and is attached to the driver's metal frame, called the basket. • The narrow end of the cone is connected to the voice coil. • The coil is attached to the basket by the spider, a ring of flexible material. The spider holds the coil in position, but allows it to move freely back and forth. • Some drivers have a dome instead of a cone. A dome is just a diaphragm that extends out instead of tapering in.
Three types… Tweeter Mid Range Woofer
Size reasoning • To create higher frequency waves -- waves in which the points of high pressure and low pressure are closer together -- the driver diaphragm must vibrate more quickly. • This is harder to do with a large cone because of the mass of the cone. • Conversely, it's harder to get a small driver to vibrate slowly enough to produce very low frequency sounds. It's more suited to rapid movement.
Types of Enclosures Sealed enclosure Bass reflex enclosure • No air can escape. • Internal air pressure changes constantly based on which way the wave (cone) is moving. • Requires more energy to overcome air pressure • More precise sound reproduction. • Redirect the inward pressure outward, using it to supplement the forward sound wave. • Accomplished by a small port in the enclosure. • Requires less energy • Less precise sound reproduction.
Similar to the enclosure system • The PASSIVE speaker is not hooked to current. Relies only on the pressure waves created by the active speaker. • Used in rear-speakers of surround sound systems.
Your assignment • Surround Sound Research • How is surround sound achieved? • What role did DOLBY have in this? • What was one of the earliest movies to employ surround sound? • What does the term “5.1” mean?
Effects • EFFECTS are alterations done to the original signal. • These can be either GAIN-based or TIME-based • Gain based – alters the amplitude of the signal • Time based – alters via time manipulation
Reverberation • http://www.mcsquared.com/reverb.htm • “Reverb” happens naturally – based on what reflects the wave in a room. • From any sound source, say a speaker of your stereo, there is a direct path that the sounds covers to reach our ears. But that's not the only way the sound can reach us. • Sound waves can also take a slightly longer path by reflecting off a wall or the ceiling, before arriving at your ears.
Delay • You can use a long delay to layer notes. • Create interesting rhythms as a result • http://en.wikipedia.org/wiki/Delay_%28audio_effect%29
Multi-Tap Delay • In some cases, you might want more flexibility in a delay unit, and a multi-tap delay offers gives you just this. • Multi-tap delays are interesting because they allow you to create more complex patterns that can add a rhythmic quality to the instrument.
Ping-Pong Delay • The ping-pong delay produces a bouncing sound, where it's typically bouncing between the left and right channels of a stereo signal.
Flanging • Flanging has a very characteristic sound that many people refer to as a "whooshing" sound, or a sound similar to the sound of a jet plane flying overhead. • Clip – first time, normal, second time with effect • http://en.wikipedia.org/wiki/Flanging
Chorusing • Just as a chorus is a group of singers, the chorus effect can make a single instrument sound like there are actually several instruments being played. • It adds some thickness to the sound, and is often described as 'lush' or 'rich'. • First time – normal, second time – with effect • http://en.wikipedia.org/wiki/Chorus_effect
Connections • Speakers • ¼” • Speakon Jacks • Standard Speaker Wire • Microphones • XLR Cables
Microphone Cables • XLR • Cannon X Series (original maker) • Latch (so they don’t fall out) • Rubber (surrounding the female end for insulation) • Typically have 3 connectors • 1 is a ground for electrical currentOther two are positive/negative leads • Which types of microphones need phantom power?
Standard Speaker Cable • Typically used in home wiring • Two wires – positive & negative
TRS Connectors • The positive/negative charge comes from the ringson the plug
Also known as… • A TRS connector has… • TIP • RING • SLEEVE • Invented for telephone switchboards • Also used for electrical instruments such as guitars and keyboards.
Speakon Cables • Newest of the technologies • Used in professional settings • Drastically eliminates • Shock possibilities • Loose connections during a performance
RCA Cables • A “stylized” version of the standard speaker wire • Are quite universal. • Red – Right Channel • White – Left Channel (or a MONO channel) • Yellow – Video • Used in a wide variety of applications • Disadvantage: • Each channel requires its own cable
Optic Cable (aka Fiber Optics) • TOSLink • Toshiba Link • Carries the signal using light, not electricity • Primarily found in home theater systems. • Not really used on the pro level.