In the digital domain, audio that is too loud or too quiet can encounter similar problems as with the analog domain. Matt explains how amplification and attenuation (turning the volume up or down) works within digital gain stages using multiplication. When samples go outside the range of available measurements, this is called clipping distortion. Rounding errors, also known as quantization distortion, can happen at very low amplitudes unless dither is enabled.
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- In the analog domain, a gain stage,…a place where we can turn an audio signal up or down,…works using an electrical circuit.…In the digital domain, a gain stage works using math.…Specifically, multiplication and division.…Here's how a gain stage works in the digital domain.…(piano chord)…This recorded sound is made up of several thousand samples.…Now, if we tell the audio software…to turn up the sound by six decibels, then,…behind the scenes, the computer actually goes through…each of those thousands and thousands of samples…and multiplies its value by two.…
(louder piano chord)…Or, if we turn the sound down by six decibels,…the computer divides each sample measurement in half.…(softer piano chord)…The specific amount that the computer uses…to multiply or divide are different…for different decibel amounts of volume change…but the principle is the same.…This is one reason older computers,…from the 1990s or earlier, couldn't work as well…with digital audio.…
They couldn't do all that math quickly enough.…In the analog domain,…
The course starts with explanations of what sound really is and how we hear it, including discussions on frequency, amplitude, phase, and psychoacoustics. Matt explores analog audio signal path, explaining connections, gain staging, and metering. Next, he brings the audio signal into the digital domain, discussing analog to digital conversion, digital gain staging, file formats and compression, and dither.
Then the course digs into digital audio workstations (DAWs), explaining the concepts and misconceptions involved in digital recording systems. Matt describes how memory, CPU speed, and storage affect your DAW's performance, as well as how to manage computer resources and understand the plethora of file formats associated with digital recording. He follows with an overview of MIDI: how to generate, store, process, and communicate MIDI data. He wraps up with the audio processors that are often used for mixing in a DAW—including EQ, compressors, reverb, delay, and many others.
- What is sound?
- The three domains of sound: acoustic, analog, and digital
- The analog vs. digital signal paths
- Converting analog audio to digital
- Digital formats and data compression
- Understanding the five types of DAWs
- Recording performances with MIDI
- Mixing and processing audio with EQ, compression, and other effects