Digital Audio Overview PDF

**1. Digital Audio Overview** - **Analog-to-Digital Conversion**: Converts continuous analog signals into discrete digital data. - **Sample**: A snapshot of an audio signal, similar to a frame in a video. - **Sample Rate**: The number of samples taken per second. For...

**1. Digital Audio Overview** - **Analog-to-Digital Conversion**: Converts continuous analog signals into discrete digital data. - **Sample**: A snapshot of an audio signal, similar to a frame in a video. - **Sample Rate**: The number of samples taken per second. For example, CD audio has a sample rate of 44.1 kHz (44,100 samples per second). - **Nyquist Theorem**: To accurately digitize audio, the sample rate must be at least twice the highest frequency of the signal to avoid **aliasing** (unwanted distortions). Use **anti-aliasing filters** to eliminate frequencies above half the sample rate. **2. Audio File Attributes** - **File Formats**: - **Uncompressed**: WAV, AIFF. - **Compressed**: MP3, FLAC, Dolby AC3. - **Key Properties**: - **Sample Rate**: Affects audio quality and file size. - **Bit Depth**: Number of bits per sample, influences audio resolution and dynamic range. - **Channels**: Mono, stereo, or multi-channel. - **Compression**: Can be lossy (e.g., MP3) or lossless (e.g., FLAC). **3. Sample Rate and Bit Depth** - **Sample Rate**: Higher rates improve fidelity but increase file size and processing power needs. Lower rates reduce file size but may lower quality. - **Bit Depth**: The number of bits per sample; higher bit depths provide more dynamic range and lower quantization errors. - **Common Bit Depths**: - CDs: 16-bit. - DVDs/Blu-ray: 24-bit. - DAWs: 16, 24, or 32-bit options. - **Dithering**: Adds low-level noise to minimize errors when lowering bit depth. **4. Word Clock** - **Word Clock**: Synchronizes digital audio devices for sample accuracy. - Higher-quality clocks reduce **jitter** (phase distortions). - **Connection Types**: AES, S/PDIF, ADAT, BNC (coaxial). **5. Recording Setup Essentials** - **Computer**: High RAM, solid-state drive (SSD) for DAW data. - **Digital Audio Workstation (DAW)**: Choose based on workflow preferences (e.g., Pro Tools, Logic). - **Audio Interface**: Examples include Focusrite Scarlett, Universal Audio Apollo Twin. - **Microphones and Monitors**: A quality mic is essential for recording; headphones help in early mixing. **6. Digital Audio Documents** - **DAW File Management**: Keep session files organized. Ensure audio files stay within their parent folders (crucial for software like Pro Tools). - **File Optimization**: Reducing file size for efficient storage and transmission (e.g., internet). **7. Audio File Manipulation** - **Optimizing**: Compresses files for smaller size (lower quality). - **Transcoding**: Converts files between formats without compression. - **Codecs**: - **Lossy**: Sacrifices some quality for smaller file sizes (e.g., MP3). - **Lossless**: Compresses without losing information (e.g., FLAC). **8. Importing/Exporting Files in DAWs** - DAWs allow for the import/export of audio, MIDI, and other formats. - **Import**: Audio, MIDI, session files. - **Export**: Tracks, projects, scores (e.g., in Logic, Final Cut XML). **9. Non-Destructive Editing** - **Non-Destructive**: Edits do not permanently alter the original file. Effects and trims are applied without overwriting the source. - **Destructive Editing**: Permanently modifies the file.