Simple Explanation

A standard reference level for signal strength in professional audio gear.

Concise Technical Definition

+4 dBu is a professional line-level reference voltage equal to 1.23 volts RMS, used as a nominal operating level in audio systems.

Layman-Friendly Analogy

Think of it like a healthy speaking volume in a conversation—strong enough to be heard clearly without shouting.

Industry Usage Summary

+4 dBu is the standard for balanced line-level signals in professional audio systems, used in mixers, interfaces, and studio gear for optimal signal-to-noise performance.

Engineering Shortcut

+4 dBu = 1.23 V RMS; pro audio line level standard.

Full Technical Explanation

+4 dBu is a reference voltage used to define standard line-level audio signals in professional environments. The unit "dBu" is a decibel value referenced to 0.775 volts RMS. Therefore, +4 dBu corresponds to approximately 1.23 volts RMS. This level is used for balanced audio signals to ensure compatibility, headroom, and low noise across professional gear. It contrasts with -10 dBV, a lower consumer-level standard used in home audio systems. Understanding this distinction is crucial for interfacing different equipment types without signal degradation.