Live sound engineering requires electronic equipment. Let's look closer at this equipment and discuss its various functions.
Sound engineering uses equipment such as amplifiers, microphones, audio lines, monitors and mixing boards to control and direct the various sounds emitted by the musical group on stage. Each of these items has specific functions that enable the sound engineer to control the overall audio experience. Together, they capture the sounds made by the musical group and pump them up and send them out to the audience.
Many times, the process starts with a microphone. A microphone uses a diaphragm that moves with air pressures created by sounds, such as a voice. The diaphragm converts this mechanical movement into electrical signals, which are sent down an audio line to an amplifier or other destination, such as an effects box.
Amplifiers are a crucial piece of equipment. Amplifiers take a small sound, such as the nearly silent pluck of an electric guitar string, and enlarge it, making it many times louder. In some cases, musicians plug their instruments directly into an amplifier, such as in the case of an electric guitar. In others, the sound engineer uses a microphone to pick up the sound from a non-electric instrument, such as a set of drums, to feed the sound into the amplifiers. Musicians and sound engineers can also add effects into the sound coming through amplifiers. These might include reverb, which is a kind of echo effect, or "fuzz," a distortion that makes instruments sound rough and edgy.
You've already heard us discuss audio lines. These cables are metal wires wrapped in rubber and can be any length. Their function is to take different electrical signals, from microphones or instruments, for example, and carry them to another piece of equipment.
Monitors and other speakers are the end release point for the amplifiers, or where the sounds come out. Monitors, specifically, are orientated toward the musical group members, and allow them to "hear themselves" as they sound over the amplification system. Monitors are speakers that allow the group members and live sound engineer to monitor the overall audio of the performance.
Mixing boards are large panels of buttons and knobs that control many of the sound qualities coming from the amplifiers. We'll talk more about that in the next section.