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Chapter 02 audio recording - part ii


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Chapter 02 audio recording - part ii

  1. 1. Chapter 02: Audio Recording - Part II <ul><li>Prepared by: Nur Muizz Mohamed Salleh </li></ul>Date: 22 November 2010
  2. 2. Talk Layout <ul><li>The Computer and Audio </li></ul><ul><li>The Digital Recording / Reproduction Process </li></ul><ul><li>Audio Recording System </li></ul>
  3. 3. Overview <ul><li>In order to put that information to use, an overview of the gear used is needed. </li></ul><ul><li>The equipment, devices, software and setup that you use are what make up the entire digital audio rig. </li></ul><ul><li>The quality of this gear will make significant difference in the audio output and the overall sound design. </li></ul><ul><li>In the beginning, any gear will do, but techniques and more importantly, the ear start to “sharpen”, more advanced gear will be wanted. </li></ul>
  4. 4. Overview <ul><li>the general setup for entire rig also important to understand. </li></ul><ul><li>there are specific locations for monitors, the chair and other gear that will help in the appreciation and analysis of project work. </li></ul><ul><li>A “5.1 surround sound” setup is also critical for surround mixing to take place. </li></ul>
  5. 5. Overview <ul><li>the sound generated by your system is like an “aural fingerprint”. </li></ul><ul><li>your sound will leave an impression on the listener, eventually leading to a characteristic style. </li></ul><ul><li>weak physical links in the audio chain will become apparent when tested on proper gear. </li></ul>
  6. 6. Overview <ul><li>eg: mixing through mediocre monitors might alter the overall mix and thus sound very poor through a commercial system - even worse in semiprofessional and professional sound rig. </li></ul><ul><li>the better the gear and software the cleaner the audio product will be. </li></ul>
  7. 7. The Computer & Audio <ul><li>Hardware </li></ul><ul><ul><li>The power and accuracy of your computer will determine the quality of your audio whether it is input or output. </li></ul></ul><ul><ul><li>The knowledge of how to construct a computer from the various available components is a valuable skill to have. </li></ul></ul><ul><ul><li>It can help to cut costs over the pre-made towers and allows you to pick and choose - the exact configuration. </li></ul></ul>
  8. 8. The Computer & Audio <ul><li>Hardware- cont </li></ul><ul><ul><li>Basically there are 9 devices in computer that should be understood: </li></ul></ul><ul><ul><ul><li>The Central Processing Unit (CPU) </li></ul></ul></ul><ul><ul><ul><li>motherboard </li></ul></ul></ul><ul><ul><ul><li>Random Access Memory (RAM) </li></ul></ul></ul><ul><ul><ul><li>Hard Drive </li></ul></ul></ul><ul><ul><ul><li>Tower with power supply </li></ul></ul></ul><ul><ul><ul><li>modem / ethernet card. </li></ul></ul></ul><ul><ul><ul><li>graphic card </li></ul></ul></ul><ul><ul><ul><li>sound card </li></ul></ul></ul><ul><ul><ul><li>peripheral device connection - keyboard,mouse, mixer, monitor or other external </li></ul></ul></ul>
  9. 9. The Computer & Audio <ul><li>Power Plant (CPU) </li></ul><ul><ul><li>The core of the entire machine. </li></ul></ul><ul><ul><li>A faster CPU allows more streams of audio to be recorded or played back at a time. </li></ul></ul>
  10. 10. The Computer & Audio <ul><li>Motherboard </li></ul><ul><ul><li>Is where all of the main processing occurs and where all of the data & power infrastructure for the computer are. </li></ul></ul><ul><ul><li>various attachable cards performing various functions all plug into similar sockets on a common motherboard. </li></ul></ul>
  11. 11. The Computer & Audio <ul><li>Random Access Memory (RAM) </li></ul><ul><ul><li>Allow data to be stored in a temporary location, which makes it easier and faster to access than the hard drive. </li></ul></ul><ul><ul><li>The more RAM the better. </li></ul></ul><ul><ul><li>Most machine have slots to increase RAM capacity. </li></ul></ul>
  12. 12. The Computer & Audio <ul><li>Hard Drive </li></ul><ul><ul><li>Need to be fast for audio needs. </li></ul></ul><ul><ul><li>The higher the resolution of your audio file, the more throughput you will need from your hard drive. </li></ul></ul><ul><ul><li>The general project size basically determines the amount of space needed, but the is more to it than that. </li></ul></ul>
  13. 13. The Computer & Audio <ul><li>Graphic Card </li></ul><ul><ul><li>Video games require high frame rates, which require a faster render times generated from the graphic card. </li></ul></ul><ul><ul><li>if your card can handle video games, it can easily handle audio. </li></ul></ul>
  14. 14. The Computer & Audio <ul><li>Sound Card </li></ul><ul><ul><li>the heart of an audio-configured computer is the sound card. </li></ul></ul><ul><ul><li>today PC or Mac can handle just about any audio needs. </li></ul></ul><ul><ul><li>the higher the end you go, the more complex and expensive things get and more power you will need. </li></ul></ul>
  15. 15. The Computer & Audio <ul><li>Tower </li></ul><ul><ul><li>the tower is where all of the components of your computer reside. </li></ul></ul><ul><ul><li>the main thing to keep in mind when purchasing a tower is whether the power supply built into the tower is strong enough to power your cards and devices. </li></ul></ul>
  16. 16. The Computer & Audio <ul><li>Software </li></ul><ul><ul><li>there are hundreds of software packages that you can use to create audio assets. </li></ul></ul><ul><ul><li>the industry is moving forward in making audio packages integrated with video packages. </li></ul></ul><ul><ul><li>most of applications now allow you to do just about everything in a video application as you can in a dedicated audio application. </li></ul></ul>
  17. 17. The Computer & Audio <ul><li>Software - cont </li></ul><ul><ul><li>Example of the application are: </li></ul></ul><ul><ul><ul><li>Digidesign ProTools </li></ul></ul></ul><ul><ul><ul><li>Steinberg Nunendo </li></ul></ul></ul><ul><ul><ul><li>Sony Sound Forge </li></ul></ul></ul><ul><ul><ul><li>Apple’s Logic </li></ul></ul></ul><ul><ul><ul><li>Adobe Audition etc </li></ul></ul></ul>
  18. 18. The Computer & Audio <ul><li>Software - cont </li></ul><ul><ul><li>The essential features that are required to successfully create and implement audio assets should be located in one or two applications on your rig. </li></ul></ul><ul><ul><li>Usually no need for 5 apps that all perform the same functions. </li></ul></ul><ul><ul><li>there are many other add-ons or plug-ins that can be applied to these, but these are circumstantial and many times costly. </li></ul></ul>
  19. 19. The Computer & Audio <ul><li>Software - cont </li></ul><ul><ul><li>Recording, editing and adding effects and processes to audio files are the most common tasks you will do with an audio software apps. </li></ul></ul><ul><ul><li>Each one is relatively easy to understand but, as with any creative enterprise, the trick is in knowing where and when to use them and how to apply them. </li></ul></ul>
  20. 20. The Digital Recording / Reproduction Process <ul><li>The following sections provide a basic overview of the various stages that are encountered within the process of encoding analog signals into equivalent digital data (Figure A) </li></ul><ul><li>and then converting this data back into its original analog form (Figure B). </li></ul>
  21. 21. The Digital Recording / Reproduction Process <ul><li>Figure A: Digital Audio Chain: Recording </li></ul>
  22. 22. The Digital Recording / Reproduction Process <ul><li>Figure B: Digital Audio Chain: Reproduction </li></ul>
  23. 23. The Digital Recording <ul><li>The digital recording chain includes a low-pass filter, a sample-and-hold circuit, an analog-to-digital converter, and the circuitry for signal coding and error correction. </li></ul><ul><li>At the input of a digital sampling system, the analog signal must be band-limited with a low-pass filter so as not to allow frequencies that are greater than half the sample rate frequency to pass into the A/D conversion circuitry. </li></ul><ul><li>Filter generally makes use of a roll-off slope at its high-frequency cutoff point (as an immediate or ‘‘brickwall’’ slope would introduce severe signal distortion and phase shifts). </li></ul>
  24. 24. The Digital Recording <ul><li>In order for the full bandwidth to be accurately encoded, the Nyquist theorem requires that a sampling rate be chosen that’s higher than twice the highest frequency to be recorded. </li></ul><ul><li>For example, a system with a bandwidth that reaches into the 20-kHz range is often sampled at a rate of at least 44.1K samples per second. </li></ul>
  25. 25. The Digital Recording <ul><li>Following the low-pass filter, a sample-and-hold (S/H) circuit holds and measures the analog voltage level for the duration of a single sample period, which is determined by the sample rate (i.e., less than 1/44,100th of a second). </li></ul><ul><li>At this point, computations must be performed in order to translate the sampled level into an equivalent binary word. </li></ul><ul><li>This step in the A/D conversion is a critical component of the digitization process, as the sampled DC voltage level must be accurately quantized into an equivalent digital word (to the nearest step level) in a very short period of time. </li></ul>
  26. 26. The Digital Recording <ul><li>Once the sampled signal has been converted into an equivalent digital form, the data must be conditioned for further data processing and storage. </li></ul><ul><li>This conditioning includes data coding, data modulation, and error correction. </li></ul><ul><li>In general, the binary digits of a digital bitstream aren’t directly stored onto a recording medium as raw data; rather, data coding is used to translate the data (along with synchronization and address information) into a form that allows the data to be most efficiently and accurately stored. </li></ul>
  27. 27. Reproduction Process <ul><li>the digital reproduction chain works in a manner that is complementary to the digital encoding process. </li></ul><ul><li>Since most digital media encodes data onto media in the form of highly saturated magnetic transition states or optical reflections, the recorded data must first be reconditioned in a way that restores the digital bitstream back into its original, modulated binary state. </li></ul><ul><li>Once this is done, the data can then be de-interleaved (reassembled) back into its original form, where it can be converted back into PCM data. </li></ul>
  28. 28. Audio Recording System <ul><li>Hard-Disk Recording: </li></ul><ul><ul><li>Although the field of hard-disk recording has matured into a technology that’s become pervasive in all forms of media production, it’s still in a continual form of evolution as hardware, software, and personal working styles change. </li></ul></ul><ul><ul><li>As with all evolutionary revolutions, it’s always a good idea to keep abreast of these changes by reading the trade magazines, searching the Web, and keeping your eyes and ears open. </li></ul></ul><ul><ul><li>For the remainder of this chapter, we’ll be looking at the various types of hard disk systems that are currently available on the market </li></ul></ul>
  29. 29. Audio Recording System <ul><li>Advantages of Hard-Disk Recording: </li></ul><ul><ul><li>The ability to handle long sample files —Hard-disk recording time is often limited only by the size of the disk itself. </li></ul></ul><ul><ul><li>Random-access editing —Once audio (or any type of data) is recorded onto a disk, any point within the program can be instantly accessed at any time, regardless of the order in which it was recorded. </li></ul></ul>
  30. 30. Audio Recording System <ul><li>Advantages of Hard-Disk Recording - cont: </li></ul><ul><ul><li>Nondestructive editing —This process allows audio segments (often called regions) to be placed back in any context and/or order within a program without changing or affecting the originally recorded sound file in any way. Once edited, these edited tracks and/or segments can be reproduced to create a single, cohesive program. </li></ul></ul><ul><ul><li>DSP —Digital signal processing can be performed on a sound file and/or segment in either real time or non-real time (often in a nondestructive fashion). </li></ul></ul>
  31. 31. THANK YOU <ul><li>Q & A Session </li></ul>