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.  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

What would be the benefits/drawbacks of the two options?

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 Lavalier mic Wireless mic Pressure Zone mic Kick Drum mic Omnidirectional mic Cardioid Mic Bi-Directional mic http://www.youtube.com/wat ch?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.

Usually are combined into an enclosure.

Types of Enclosures No air can escape. 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 Microphones ¼” Speakon Jacks Standard Speaker Wire Microphones XLR Cables

Microphone Cables XLR Typically have 3 connectors 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 current Other two are positive/negative leads Which types of microphones need phantom power?

Speaker Cables

Standard Speaker Cable Typically used in home wiring Two wires – positive & negative

TRS Connectors The positive/negative charge comes from the rings on 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

Speakon Cables Newest of the technologies Used in professional settings Drastically eliminates Shock possibilities Loose connections during a performance

A combo jack – all 3!

RCA Cables

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.