Reference level (sound engineering)
The term reference level has two different meanings in sound engineering :
- On the one hand, a level is referred to as a reference level if it relates to a specific level specification; this is then the reference value . For example, the reference level for the level unit dBu can be 0 dBu = 775 mV ( effective ).
- On the other hand, the reference level can be a level for which a certain device, an input, an output or an entire device chain is designed; here the reference level is the same as the nominal level.
International reference values
Level unit | Ref.value | Physical size | comment | field of use |
---|---|---|---|---|
0 dBu | U 0 = 0.775 V eff | tension | Voltage that converts 1 mW eff power into 600 ohms | Audio, technology, telecommunications |
0 dBV | U 0 = 1 V eff | tension | corresponds to 2.22 dBu | Audio, technology, USA |
0 dBm | P 0 = 1 mW eff | power | Reference value at R = 600 Ohm | Telecommunication technology |
Reference value at R = 50 Ohm | HF technology | |||
Reference value at R = 75 Ohm | HF technology (television) |
Comparison of important sound levels
For radio and television, the analog reference level or nominal level was set at +6 dBu according to an ARD agreement, corresponding to 1.55 V (effective). It refers to a level of 0 dBu at 0.775 V (rms value) and is measured with a standardized level meter.
In the area of the EBU (European Broadcasting Union) and the ARD (working group of the public broadcasters of the Federal Republic of Germany), this corresponds to the scale value −9 dBFS (FS = full scale) in digital signal processing . Analog-to-digital converters and digital-to-analog converters for audio signals are adjusted accordingly. The equation +6 dBu = −9 dBFS = 0 dBr ( relative to the studio level or full scale) is not a general rule, but is based solely on an agreement between the members of the ARD broadcasters. A different setting (leveling) of AD and DA converters and especially the use of non-standard level meters lead to completely different dB values.
The analog reference level of +4 dBu comes from the USA , corresponding to 1.228 V (rms value) for the sound engineering and the sound reinforcement .
There is also the reference level of 0 dBV, corresponding to exactly 1 V (effective) and the home device level (USA) with −10 dBV, corresponding to 0.3162 V (effective).
dB ( sound pressure level ) | dBV (consumer electronics) | dBu (TV BRD ) | dBu (TV USA ) | dBr (studio level) | dBFS (digital level) | |
---|---|---|---|---|---|---|
Clip border | ( Pain threshold ) | ( Distortion ) | +15 dBu ( distortion ) | +22 dBu ( distortion ) | ( Distortion ) | 0 dBFS |
Full scale | - | -10 dBV (= -7.78 dBu = 0.3162 V eff ) |
+6 dBu (= 1.55 V eff ) |
+13 dBu | 0 dBr | -9 dBFS |
standardized test tone | - | -19 dBV | -3 dBu | +4 dBu (= 1.228 V eff ) |
-9 dBr | -18 dBFS |
Reference value | Hearing threshold (2 · 10 −5 Pa ) = 0 dB |
0 dBV = 1 V eff | 0 dBu = 0.775 V eff | Full scale | Clipping |
See also
literature
- Michael Dickreiter, Volker Dittel, Wolfgang Hoeg, Martin Wöhr (eds.), "Handbuch der Tonstudiotechnik", 8th, revised and expanded edition, 2 volumes, publisher: Walter de Gruyter, Berlin / Boston, 2014, ISBN 978-3- 11-028978-7 or e- ISBN 978-3-11-031650-6 .
- Thomas Görne: Microphones in theory and practice. 8th new, revised and expanded edition. Elektor-Verlag, Aachen 2007, ISBN 978-3-89576-189-8 .
- Thomas Görne: Sound engineering. Fachbuchverlag Leipzig by Carl Hanser Verlag, Munich a. a. 2006, ISBN 3-446-40198-9 .
- Roland Enders: The home recording manual. The way to optimal recordings. 3rd, revised edition, revised by Andreas Schulz. Carstensen, Munich 2003, ISBN 3-910098-25-8 .
Web links
- Sound quantities , their levels and the reference value sengpielaudio.com
- dB conversion - dBu - dBV - Volt (RMS) sengpielaudio.de
- Reference level adt-audio.de
Individual evidence
- ↑ sennheiser.com/Glossary ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. Glossary, section dBV