Line level

The reference level is a term used in sound engineering.

There are two different meanings of the term. On the one hand, a level is called the reference level when it refers to a specific level indication. For example, = 775 mV be ( effectively ) for the level dBu reference level of 0 dBu. On the other hand, the reference level can be a level for which a specific device, an input, an output, or an entire chain of devices is designed here reference level is equal to the nominal level.

For radio and television, the analog reference level or nominal level of ARD agreement was determined according to 6 dBu, corresponding to 1.55 V ( rms). It refers to a level of 0 dBu at 0.775 V ( rms) and is measured with a standard VU meter.

In the area of ​​EBU (European Broadcasting Union) and ARD ( Association of Public - service broadcasters of the Federal Republic of Germany ) corresponding to this in the digital signal processing is graduated to -9 dBFS (FS = full scale). Analog -to-digital converters and digital - to-analog converters for audio signals are adjusted accordingly.

From USA is the analog reference level of 4 dBu, corresponding to 1.228 V ( RMS ) for audio engineering and sound reinforcement.

There is also the reference level of 0 dBV, corresponding exactly 1 V ( rms) and the home device level ( USA) -10 dBV, corresponding to 0.3162 V ( rms).

International reference values

Comparison of important sound level

The " rule of three " 6 dBu ( rms) = -9 dBFS = 0 dBr (peak value) is no universal rule but based solely on an agreement between the members of the ARD broadcasting organizations themselves. A different setting ( level adjustment ) of AD and DA converters, and in particular the use of non " standard-compliant " VU lead to completely different dB values ​​.