linelevel

Line level, or line-level audio, refers to the nominal signal level used to interconnect audio equipment. It is the standard for consumer and professional devices to pass audio between components such as players, mixers, processors, and amplifiers. It is distinct from mic level, which is much lower, and instrument level, which is typical for electric instruments.

Typical levels are defined as -10 dBV for consumer line level, roughly 0.316 volts RMS, and +4 dBu for professional line level, about 1.23 volts RMS, with dBu referenced to 0.775 volts. The choice of level affects gain staging: mismatches can lead to noise or distortion if signals are too low or too hot.

Impedance and connections: Line-level signals are designed for high-impedance to minimize loading. Input impedances are commonly in the kilohms to tens of kilohms range. Line connections are carried via balanced or unbalanced formats. Professional gear typically uses balanced connections (XLR or TRS) for noise rejection; consumer gear often uses unbalanced RCA or 1/4 inch TS.

Uses and considerations: Line level is intended for short to medium cable runs within a system and is not optimized for microphone pickup. Some gear offers pad switches or attenuators to prevent distortion when interconnecting devices with higher output levels. When patching, matching nominal levels and ensuring appropriate impedance helps maintain signal integrity.

Related terms include instrument level and mic level, as well as line input and line output labels found on mixers, audio interfaces, and consumer audio equipment.