Line level refers to the standardized signal level used for connecting audio equipment, such as mixers, amplifiers, and recording devices. It is typically a relatively high signal level, around 0.316 volts root mean square (VRMS) or +4 dBu, and is intended to be a balanced, low-impedance signal that can be transmitted over long distances with minimal degradation.

Line level signals are typically used for connecting audio sources that have their own internal amplification, such as CD players, synthesizers, and preamplifiers. They are also used for connecting professional audio equipment, such as mixing consoles, to external processors or recording devices.

Line level signals are distinguished from other types of audio signals, such as microphone level and instrument level, which have lower signal levels and require different types of preamplification to bring them up to the appropriate level for processing.

In audio recording, it is important to match the line level of the audio source to the line level of the recording device or mixer to ensure an optimal signal-to-noise ratio and prevent distortion. Many audio devices have adjustable input gain controls or input sensitivity switches that can be used to adjust the level of the incoming signal to match the line level of the device.

What’s the Difference Between Line Levels and Mic Levels?

Line level and mic level are two different signal levels used in audio recording and processing. The main differences between line level and mic level are:

• Signal Level: Line level signals are typically stronger than mic level signals. Line level signals are around 0.316 volts root mean square (VRMS) or +4 dBu, while mic level signals are typically in the range of 1 to 100 millivolts (mV) or -60 to -40 dBu.
• Impedance: Line level signals are designed to be low-impedance signals, which means they can be transmitted over long distances with minimal degradation. Mic level signals, on the other hand, are typically high-impedance signals, which require special preamplification to boost their signal level and impedance.
• Sources: Line level signals are typically used for connecting audio sources that have their own internal amplification, such as CD players, synthesizers, and preamplifiers. Mic level signals, on the other hand, are typically used for connecting microphones, which do not have their own internal amplification.
• Processing: Line level signals are typically processed by mixers, amplifiers, and other audio equipment that can handle high-level signals. Mic level signals, on the other hand, require a preamplifier to boost their level and impedance before they can be processed by audio equipment.

In audio recording and processing, it is important to match the signal level of the audio source to the input level of the recording device or mixer to ensure optimal signal-to-noise ratio and prevent distortion. Many audio devices have adjustable input gain controls or input sensitivity switches that can be used to adjust the level of the incoming signal to match the line level or mic level of the device.