Chapter 1 Getting Ready .................................................................. 2 1.1 Sounds Like Fun! ....................................................................... 2 1.2 How This Book is Organized ........................................................ 2 1.3 A Brief History of Digital Sound ................................................... 2 1.4 Basic Terminology ..................................................................... 4 1.4.1 Analog vs. Digital .....................
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 1 Chapter 1 Getting Ready 1.1 Sounds Like Fun! We walk through this world wrapped in the vibrations of sound. Sounds are all around us all of the time, whether we pay attention to them or not. Most people love music. Its melodies, harmonies, rhythms, consonances, dissonances, reverberations, tonalities, and atonalities find resonance in our souls and echo in our minds.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 production required a wall full of equipment interconnected with scores of patch cables, all working together to play a single instrument's sound, live, one note at a time. The concept of using digital technology to create sound has been around for a long time. The first documented instance of the idea was in 1842 when Ada Lovelace wrote about the analytical engine invented by Charles Babbage.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 1.4 Basic Terminology 1.4.1 Analog vs. Digital With the evolution of computer technology in the past 50 years, sound processing has become largely digital. Understanding the difference between analog and digital processes and phenomena is fundamental to working with sound. The difference between analog and digital processes runs parallel to the difference between continuous and discrete number systems.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 in Hertz (samples/second). The sound being detected by the microphone is typically a combination of sound frequencies. The frequency of a sound is related to the pitch that we hear – the higher the frequency, the higher the pitch.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 Figure 1.1 Basic setup and signal flow of a digital audio workstation Secondly, it‟s possible that you‟ll also be using equipment for live performances. A live performance setup is pictured in Figure 1.2. Much of the equipment and connectivity is the same as or similar to equipment in a DAW. Figure 1.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 Thirdly, to use this book most effectively you‟ll need to gather some additional software so that you can view the book‟s learning supplements, complete some of the exercises, and even do your own experiments.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 Computer Desktop or laptop with a fast processor, Mac or Windows operating system. RAM – at least 2 GB. Hard drive – a fast hard drive (separate and in addition to the operating system hard drive) dedicated to audio storage, at least 7200 RPM. Audio interface (i.e., sound card) External audio interface with XLR connections. The audio interface may also serve as a MIDI interface.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 computer. All of these instrument samples have to be loaded into RAM so they can be instantly accessible to the MIDI keyboard. For these reasons, you'll probably need to upgrade the RAM capacity on your computer. A good place to begin is with 2 GB of RAM. RAM is easily upgradeable and can be increased later on if needed.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 400 and 800 devices on the same bus is not a good idea and may confuse your computer or hardware. Just pick one of the two speeds and make sure all your FireWire devices run at that speed. The most important factor in choosing an external FireWire hard drive is the FireWire bridge chipset. This is the circuit that interfaces the IDE or SATA hard drive sitting in the box to the FireWire bus.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 1.5.2.3 Drivers A driver is a program that allows a peripheral device such as a printer or sound interface to communicate with your computer. When you attach an external sound interface to your computer, you have to be sure that the appropriate driver is installed.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 Figure 1.5 M-Audio Oxygen8 25-key MIDI keyboard controller Figure 1.6 Edirol PCR-M50 49-key MIDI keyboard controller 1.5.2.5 Recording Devices Recording is, of course, one of the fundamental activities in working with sound. So what type of recording devices do you need? One possibility is to connect a microphone to your computer and use software on your computer as the recording interface.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 have one or two built-in microphones with the added option of connecting external microphones as well. Dedicated multitrack hardware recorders as shown in Figure 1.8 and Figure 1.9 are available for situations where portability and high channel counts are desirable. These recorders are generally very reliable but offer little opportunity for editing, mixing, and processing the recording.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 Figure 1.9 A dedicated 48-channel multitrack recorder 1.5.2.6 Microphones Your computer may have come with a microphone suitable for gaming, voice recognition, or audio/video conferencing. However, that‟s not a suitable recording microphone. You need something that gives better quality and a wider frequency response. The audio interfaces we recommend in Section 1.5.2.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 sometimes be provided by a battery. The conductive plates are very thin, and when sound waves push against them, the distance between the plates changes, varying the charge accordingly and creating an electrical representation of the sound. Condenser microphones are much more sensitive than dynamic microphones.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 about the physical relationship between the microphone and the loudspeaker.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 Figure 1.10 Shure SM58 dynamic microphone Figure 1.11 AKG C-414 condenser microphone Another way to classify microphones is by their directionality. The directionality of a microphone is its sensitivity to the range of audible frequencies coming from various angles, which can be depicted in a polar plot (also called a polar pattern).
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 Figure 1.12 Polar plot for an omnidirectional microphone A bidirectional microphone is often referred to as a figure-eight microphone. It picks up sound with equal sensitivity at its front and back, but not at the sides. You can see this in Figure 1.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 Figure 1.14 Polar plot for a cardioid microphone Figure 1.15 Polar plot for a supercardioid microphone Figure 1.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 A special category of microphone called a shotgun microphone can be even more directional, depending on the length and design of the microphone (Figure 1.17). Shotgun microphones can be very useful in trying to pick up a specific sound from a noisy environment, often at a greater than typical distance away from the source, without picking up the surrounding noise. Figure 1.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 Figure 1.18 Polar plot of a dynamic cardioid microphone, showing pickup patterns for various frequencies The sensitivity that a microphone has to sounds at Aside: Shure hosts an interactive different frequencies is called its frequency response (a tool on their website called the Shure term also used to describe the behavior of filters in later Microphone Listening Lab where you can chapters).
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 Some microphones may have a very flat frequency response on-axis but due to the directional characteristics, that frequency response can become very uneven when off-axis. This is important to keep in mind when choosing a microphone.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 achieving. In a recording situation, you can often find great success connecting these instruments directly to your recording system. Since these instrument audio outputs usually have high output impedance, you need to run the signal through a transformer in order to convert the audio signal to a format that works with a professional microphone input.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 1.5.2.8 Monitor Loudspeakers Just like you use a video monitor on your computer to see the graphical elements you‟re working with, you need audio monitors to hear the sound you‟re working with on the computer. There are two main types of audio monitors, and you really need both.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 1.5.2.9 Studio Headphones Good-quality reference monitor loudspeakers are wonderful to work with, but if you‟re working in an environment where noise control is a concern you‟ll want to pick up some studio headphones as well.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 The XLR connector shown in Figure 1.26 is widely used in professional audio systems. It is a typically round connector that has three pins. Pin 1 is for the audio signal ground, Pin 2 carries the positive polarity version of the signal, and Pin 3 carries the inverted polarity version of the signal. The inverted polarity signal is the negative of the original.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 ( ) The inverted signal containing interference is subtracted from the original signal containing interference. Figure 1.27 Interference removed on balance signal Another important feature of the XLR connector is that it locks in place to prevent accidentally getting unplugged during your perfect take in the recording.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 The ¼" phone plug and its corresponding jack (Figure 1.28) are also widely used. The ¼" plug comes in two basic configurations. The first is a Tip/Sleeve (TS) configuration. This would be used for unbalanced signals with the tip carrying the audio signal and the sleeve connecting to the shield of the cable. The TS version is used on musical instruments such as electric guitars that have electronic signal pick-ups.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 The ⁄ " or 3.5 mm phone plug shown in Figure 1.30 is very similar to the ¼" plug, but it's used for different signals. Since it's so small, it can be easily used in portable audio devices and any other audio equipment that's too compact to accommodate a larger connector. It has all the same strengths and weaknesses of the ¼" plug and is even more susceptible to damage and accidental disconnection.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 RCA cable connector RCA panel mount connector Figure 1.31 RCA connectors The DIN connector comes in many different configurations and is used for a variety of applications. In the digital audio environment, the DIN connector is used in a 5-pin 180 degree arrangement for MIDI connections, as shown in Figure 1.32. In this configuration, only three of the pins are used so a five-conductor cable is not required.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 be found on antenna cables in wireless microphone systems, and in other professional digital audio streams such as with MADI (Multichannel Audio Digital Interface). BNC male cable connector BNC female panel connector Figure 1.33 BNC connectors The D-subminiature connector is used for many different connections in computer equipment but is also used for audio systems when space is a premium (Figure 1.34).
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 connections from a power amplifier to more than one loudspeaker. The downside is that you have exposed pins on cables with fairly high-voltage signals, which is a safety concern. Usually, the safety issues can be avoided by making connections only when the system is powered off. The other potential problem with the banana connector is that it's very easy to insert the plug into the jack backwards.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 size and shape but are keyed slightly different. An NL2 cable connector can plug into an NL4 panel connector and line up to the 1+/1 pins of the NL4. But the NL4 cable connector cannot connect to the NL2 panel connector. This helps you avoid a situation where you have two signals running on the cable with an NL4 connector where the second signal would not be used with the NL2 panel connector.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 Speakon NL2 cable connector Speakon NL2 panel connector Speakon NL4 cable connector Speakon NL4 panel connector Speakon NL8 cable connector Speakon NL8 panel connector Figure 1.36 Speakon family of connectors The RJ45 connector is typically used with Category 5e (CAT5e) ethernet cable (Figure 1.37). It has a locking tab that helps keep it in place when connected to a piece of equipment.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 connector. CAT5e cable is used for computer networking, but it is increasingly being used for digital audio signals on digital mixing consoles and processing devices. RJ45 cable connector with Ethercon housing RJ45 Ethercon panel connector Figure 1.37 RJ45 connectors The Toslink connector (Figure 1.38) differs from all the other connectors in this section in that it is used to transmit optical signals.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 Male Toslink connector Female Toslink connector Figure 1.38 Toslink connectors The IEC connector (Figure 1.39) is used for a universal power connection on computers and most professional audio equipment. There are many different connector designs that technically fall under the IEC specification, but the one that we are referring to is the C13/C14 pair of connectors.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 can also create powercon patch cables that allow you to daisy chain a power connection between several devices such as a stack of self-powered loudspeakers. Powercon connectors are colorcoded. A blue connector is used for a power input connection to a device. A white connector is used for a power output connection from a device. Powercon power input cable connector.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 workstation experiences a glitch, it's usually due to some other task the computer is trying to perform at the same time, such as checking for a software update, running a virus scan, or refreshing a Facebook page. Dedicated hardware solutions like the one shown in Figure 1.41 have only one task, and they can perform that task very reliably. Figure 1.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 after analog mixers to make it easier for sound engineers to make the transition between devices. More detailed information on mixing consoles can be found in Chapter 8. Figure 1.43 Analog mixing console Music producers and sound designers for film and video do mixing as well.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 Figure 1.45 Touch device control surface app 1.5.2.13 Loudspeakers If you plan to work in sound for the theatre, then you'll also need some knowledge of loudspeakers. While the monitors we described in Section 1.5.2.8 are appropriate for studio work where you are often sitting very close, these aren't appropriate for distributing sound over long distances in a controlled way.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 Figure 1.46 Meyer UPA-1P loudspeaker 1.5.2.14 Analysis Hardware When setting up sound systems for live sound, you need to make some acoustic measurements to help you configure the system for optimal use.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 1.5.3 Software for Digital Audio and MIDI Processing 1.5.3.1 The Basics Although the concepts in this book are general and basic, they are often illustrated in the context of specific application programs. The following sections include descriptions of the various programs that our examples and demonstrations use.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 Figure 1.48 A sample editor window zoomed down to the level of the individual samples. The dots in the waveform indicate each sample. Multitrack editors divide the interface into tracks. A track is an editable area on your audio arranging interface that corresponds to an individual input channel, which will eventually be mixed with others.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 of software change all the time, so you should compare our list with similar software that is currently available. There are many software options out there ranging from freeware to commercial applications that cost thousands of dollars. You generally get what you pay for with these programs, but everyone has to work within the constraints of a reasonable budget.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 Figure 1.49 Logic Pro workspace 1.5.3.3 Cakewalk Sonar and Music Creator Cakewalk is a class of digital audio workstation software made by Roland. It features audio recording, editing, multitrack mixing, and MIDI sequencing. Cakewalk comes in different versions, all of which run only on the Windows operating system. Cakewalk Sonar is the highend version with the highest price tag.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 Figure 1.50 Cakewalk Sonar workspace, multitrack view 1.5.3.4 Adobe Audition Audition is DAW software made by Adobe. It was originally developed independently under the name “Cool Edit Pro” but was later purchased by Adobe and is now included in several of their software suites. The advantage to Audition is that you might already have it depending on which Adobe software suite you own.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 Figure 1.51 Audacity audio editing software 1.5.3.6 Reason Reason, a software synthesis program made by Propellerhead, is designed to emulate electronic musical instruments. The number of instruments you can load in the program is limited only by the speed and capacity of your computer. Reason comes with an impressive instrument library and includes a simple MIDI sequencer.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 Figure 1.52 Reason software instrument rack 1.5.3.7 Software Plug-Ins Multitrack editors include the ability to use real-time software plug-ins to process the audio on specific tracks. The term plug-in likely grew out of the days of analog mixing consoles when you would physically plug in an external processing device to the signal chain on a specific channel of an analog mixing console.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 editor. For example, you might want to change the frequency response of the audio signal on Track 1 of your project. To do this, you'd insert an equalizer plug-in on Track 1 that performs this kind of processing in real time as you play back the audio. Most DAW applications come with a variety of included plug-ins.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 Figure 1.54 Ardour, free digital audio processing software for the Linux or OS X operating systems Ardour works in conjunction with Jack, an audio connection kit, and the GUI for Jack, qjackctl. A screenshot of the Jack interface is in Figure 1.55. On the Linux platform, Jack can talk to the sound card through ALSA, which stands for Advanced Linux Sound Architecture. Figure 1.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 1.5.4 Software for Live Performances There are software packages that are used specifically in live sound. The first category is analysis software. This is software that you can run on your computer to analyze acoustic measurements taken through an analysis microphone connected to the audio interface.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 Figure 1.57 SFX playback software from Stage Research 1.6 Learning Supplements 1.6.1 Practical Exercises Practical Exercise: Setting Up Your DAW Figure 1.58 - Icon for a practical exercise Throughout the book you'll see icons in the margins indicating learning supplements that are available for that section.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 in the PDF file and go directly to the learning supplement on our website. If you're reading a printed version of the book, the learning supplements can be found by visiting our website and looking in the applicable section. The icon shown in Figure 1.58 indicates there is a supplement available in the form of a practical exercise.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 object communications. This functionality is extended with the MSP and Jitter modules. MSP supports real-time audio synthesis and digital signal processing. Jitter adds the ability to work with video. Max programs, called patchers, can be easily distributed and run by anyone who downloads the free Max runtime program. The runtime allows you to open the patchers and interact with them.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 If you can‟t afford Max, you might consider a free alternative, Pure Data, created by one of the originators of Max. Pure Data is open source software similar to Max in functionality and interface. However, the included documentation is not nearly as comprehensive. For the Max programming exercises that involve audio programming, you might be able to use Pure Data and save yourself some money. 1.6.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 Figure 1.64 MATLAB mathematical modeling environment GNU Octave is an open source alternative to MATLAB that runs under the Linux, Unix, Mac OS X, or Windows operating systems. Like MATLAB, its specialty is array operations.
Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 7/29/2013 This book is intended to be useful not only to musicians, digital sound designers, and sound Aside: Because the audio processing engineers, but also to computer scientists implemented in these exercises is done at a fairly low level of abstraction, the solutions specializing in digital sound.