It is common for audio engineers to work with many signals simultaneously. In live sound, there might be dozens of microphones used to capture the concert performance. Each signal is sent to engineer at the front-of-house to create the mix for the audience.
In the studio, an engineer works with the audio files from a multi-track recording to create a single stereo file. As part of the mix, the engineer might include additional signals from effects like reverb, echo, compression, etc.
Therefore, an important task for audio engineers to perform is the process of combining signals together.
One way to combine signals is the process of “mixing” or “blending,” as described in the previous live sound and recording studio examples. When working with digital signals, this process is called digital summing.
Another way to combine signals is the process of amplitude modulation. This involves scaling the amplitude of one signal relative to the amplitude of another signals. This process is used to create the Tremolo effect.
In this section, we will look at these different methods of combining signals together. First, let’s consider the process of adding signals together.