Petelin, Roman, and Yury Petelin.
PC Music Home Studio: Secrets, Tips, & Tricks
Wayne: A-LIST, 2002.– 640 p.
ISBN 1931769079
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We dedicate this book to our daughter and granddaughter, Anna.
Introduction
The development of software intended for sound processing and music editing is progressing at a rapid rate, and the functionality of musical software is constantly being improved and enhanced. This is not only due to the fact that the mathematicians and engineers developing this software are mastering the secrets of musical art, but also because they suggest new technical and mathematical methods of solving tasks, both purely musical ones and those that are both musical and acoustic. It thus gradually happend that musical skills and advanced PC user skills are no longer sufficient for someone who wishes to use the PC for creative activity. Currently, if you want to create music on your PC, you'll need to master scientific terminology, understand the ideas behind operations on sound data, and know the algorithms for processing musical material implemented in musical software.
Of course, it is rather difficult to master the scientific basics of all the new technologies implemented in musical software. In these early years of the 21st century, musical software for the PC has managed to employ the results of scientific investigations in the fields of mathematics, technical cybernetics, and signal processing theory. For example:
- Optimum processing, correlation, and spectral analysis of signals exposed to interference with various statistical properties
- Synthesis of sounds with a specified time-frequency distribution in non-traditional orthogonal bases
- Adaptive methods of analog-to-digital conversion
- Polynomial approximation of the amplitude-frequency responses of the filters
- Elimination of distortions using signal interpolation with the maximum likelihood method
Even recent advances in the field of artificial intelligence and psycho-acoustics are now serving the needs of music.
It is neither fair nor realistic to require the musician to master all of the above-listed skills. Such a task is only within the power of those with encyclopedic knowledge. Still, it is impossible to accomplish anything without an understanding of some principally important aspects.
Contemporary books on the theory of signals contain several aspects that are fundamentally important for the sound engineer or sound producer: statistical radio engineering, spectral theory, theory of digital signals, information on analog and digital filters, etc. However, these books are mainly intended for mathematically skilled radio engineers, not musicians. For example, a great number of awkward mathematical expressions mask from the end-users the ideas behind the physical processes under consideration. In addition, even if you do not lose your temper and manage to carefully follow this labyrinth of formulas, it is still very difficult to find the point where mathematics intersects with music. Many of these books never even say a word on music. Naturally, scientific literature and literature on music theory exist in different dimensions.
Actually, this reasoning was partially what led us to the idea of writing a book, where, besides description of specific musical software and techniques of their usage, we could provide the theoretical information necessary to understand the basic idea of sound processing algorithms. On the other hand, we have also given ourselves the general goal of discussing fundamental ideas using the minimum number of mathematical formulas. When selecting the theoretical materials to be included in this book, we decided to limit ourselves to describing only the basic methods, algorithms, and approaches implemented in the software considered in the book.
If we tried to describe this book using one and only one phrase, we'd say that this book is on sound synthesis and sound processing. We intend to cover the following musical software:
- A sound editor
- A virtual mixer
- A virtual studios
- A sample editor
- Several plug-ins intended for digital mastering
To work efficiently with these programs, you need to properly understand spectral representation of signals, digitization of analog signals, analog and digital filtering, and dynamic processing.
We'd like to emphasize that if we were describing how to use some sound editor other than Cool Edit Pro, then it probably wouldn't be necessary to discuss mathematics and signal theory. However, a detailed investigation of Cool Edit Pro's functionality and capabilities allowed us to draw the following conclusion: Cool Edit Pro is the sound editor that implements the most advanced methods of signal processing. Such technologies are technologies of the future, ones used in space exploration. And this statement is not only figurative. Optimal filtration with an interference background (which was used when performing radar exploration of Venus) is also used in Cool Edit Pro for suppression of the noise accompanying a sound track recorded directly from a microphone. Or, take for example, the interpolation algorithm that restores the initial form of a clipped signal. This algorithm is similar to the ones that allow scientists to restore fragments of signals transferred to Earth from a space apparatus when the signals get lost due to ionosphere disturbances. And only a radio amateur who has spent hours (or, perhaps, days) tuning a 4- or 5-stage filter of a selector station can truly value the capability of synthesizing a 30th order Bessel filter with an ideal rectangular amplitude-frequency response with just a couple of mouse-clicks.
The examples provided above represent only a small part of the advanced signal processing methods implemented in Cool Edit Pro. Besides these, Cool Edit Pro also provides the following capabilities:
- Automatic matching of sound track fragments at the points where the sound wave intersects the zero level to eliminate clicks
- Universal virtual dynamic processing devices
- Special effects based on the time delay of the signal
- Software filters and equalizers capable of satisfying the most stringent requirements (and practically the same as hardware devices that would likely cost you several thousand dollars)
- The ability to influence the listener's psyche by generating oscillations synchronized with brain activity rhythms
Generally speaking, we have not encountered a more sophisticated and advanced sound editor than Cool Edit Pro. It implements such a variety of advanced scientific ideas and efficient signal processing algorithms that the theoretical part of the book could have been limited to explaining just a few of them.
We also decided that discussion of signal theory basics must be complemented by covering several practical aspects, including the following:
- Microphone design and usage
- Mixer design and usage
- The essence of the most popular acoustic effects
- Filter classification and properties
- Working principles of dynamic processing devices
- Theoretical basics and techniques of digital mastering
Naturally, we don't claim to have discovered something new when describing theory basics. Making scientific discoveries nowadays is rather difficult. The theory was formulated long ago, and is currently fully developed. On the other hand, we were not aiming to create just another thesis, either. This book is mainly aimed at providing a popular and easy-to-read description of contemporary scientific knowledge in the field of signal processing, and attempts to demonstrate their relation to the problems of musical computer technologies.
Among other problems that we have encountered, we wanted to overcome the following difficulty. Digitized musical compositions are non-stationary processes, the spectral analysis of which requires using current and instantaneous spectrums. Such spectrums are the kind calculated and displayed by Cool Edit Pro. However, most textbooks never even mention the existence of the spectral-time approach to signal analysis. Usually, only mathematical abstractions - classical Fourier spectrums calculated at an infinite time interval - are considered. Because of this, the chapters of our book dedicated to spectral analysis at finite time intervals might prove to be useful not only for musicians using their PC, but also to anyone who deals with various aspects of processing signals of any type.
Another distinguishing feature of our approach to discussing theory is the attempt to describe quite complex and advanced concepts in easy and understandable language. We'd like to point out, however, that the theoretical aspects covered here are rather complex, and can't be explained using too simplistic of an approach. To get a clear understanding of these topics, it's necessary to do some intellectual work. It's quite a job, both for your mind and your imagination.
All the theoretical materials presented here are coordinated with the elements of the software discussed in the book.
Besides the Cool Edit Pro sound editor that we have already mentioned, we will also cover the virtual toolkits that have swiftly gained popularity among computer musicians. We are speaking here about Nemesys Gigastudio 160 and Reason. These applications (especially Reason) are powerful and rather complex virtual tools intended for sound and music synthesis, and also capable of replacing extremely expensive hardware sound studios.
Even in 1997, we covered virtual synthesizers in one of our publications. At that time, however, they were more like toys. The main problem that prevented virtual synthesizers from being widely accepted was the fact that the time interval separating the instances of a key being pressed and the sound's generation was perceivable by ear. Technology has made significant advances since then, however. Modern PCs have become faster and more powerful, CPU clock speeds have grown by approximately 10 times, and large amounts of RAM (gigabytes) are no longer exotic. Developers of software whose names contain the "Giga" prefix haven't been asleep at the job either. They have managed to find convenient data formats for storing sound information, and thus have optimized playback procedures.
With the release of Reason, the dream of musicians of implementing a full-featured virtual studio has become a reality. Several years ago, the difference between compositions created in home and professional studios was obvious and clearly noticeable. The situation now has changed radically. The virtual toolkits and several hundreds of CDs with sound samples give a chance of success even to amateurs.
Thus, having briefly described the distinguishing features of the book and its concepts, let us consider the book's structure, which comprises this introduction, and 24 chapters split into 5 parts.
Part I: Acoustic Signal Conversion Theory Basics
The first part includes 4 chapters:
Chapter 1: Acoustic Signals and Their Basic Properties
Chapter 2: Spectral Representation of Signals
Chapter 3: Filtering
Chapter 4: Dynamic Processing of Acoustic Signals
Part II: Microphones, Mixers, and Effects
The second part is comprised of 2 chapters:
Chapter 5: Working with the Microphones and Mixers
Chapter 6: Sound Effects
Part III: Cool Edit Pro - a Multitrack Sound Editor
The third part consists of 12 chapters:
Chapter 7: Getting Started
Chapter 8: Working with the Main Window Using Waveform View Mode
Chapter 9: The File Menu - Working with Files
Chapter 10: The Edit Menu
Chapter 11: The View Menu - Display Management
Chapter 12: The Transform Menu - Transforming Audio
Chapter 13: The Generate Menu - Sound Generation
Chapter 14: The Analyze Menu - Analyzing Audio Data
Chapter 15: The Favorites Menu - Creating a List of the Most Often Used Operations
Chapter 16: The Option Menu
Chapter 17: The Window Menu - Managing the Main Window Pages
Chapter 18: Multitrack View - Multitrack Editing Mode
Part IV: Virtual Toolkit
The fourth part is comprised of 3 chapters:
Chapter 19: Nemesys GigaStudio 160 (V.2)
Chapter 20: Creating Your Own Sampler Libraries Using GigaStudio Instrument Editor 2.0
Chapter 21: Reason - a Virtual Sound Studio
Part V: Digital Mastering
The fifth part contains 3 chapters:
Chapter 22: Theory
Chapter 23: Mastering with T-RackS 24
Chapter 24: DirectX Plug-Ins Useful for Mastering
We actively use all software covered in this book in our everyday work. For example, it is the multitrack environment of the Cool Edit Pro sound editor that we used when preparing all materials for our radio and TV programs. When writing this book, we also put to use our experience in teaching musical computer technologies.