Loudspeaker signal

from Wikipedia, the free encyclopedia

Loudspeaker signals are the signals that are generated during normal stereo sound recording and are required for stereo loudspeaker reproduction for directional localization and spatial fanning out, as well as for staggering the depth of the sound body. They are in contrast to the ear signals that are picked up by the two ears of the person.


The signals between the loudspeakers form frequency-neutral (!) Level differences , as interchannel level differences , and transit time differences as interchannel transit times , which are decisive for the stereo process. This is the usual " stereophony ", i.e. loudspeaker stereophony . The direction of the auditory event of the phantom sound sources on the loudspeaker base can be set with the panpots (panorama controls) and the frequency-neutral level differences to be controlled with them. Δ L max = 18 dB (16 to 20 dB) apply to a full sideways direction from a loudspeaker . The phantom sound sources on the loudspeaker base must also be changed with the transit time differences of the microphone systems. Δ t max = 1.5 ms (1 to 2 ms) act depending on the signal with full sideways direction from a loudspeaker. These differences, which vary depending on the sound incidence angle , are generated by the respective stereo microphone arrangements, which thus also provide the important recording area of ​​the microphone system.


In clear contrast to this are the interaural signal differences ("between the ears") in natural hearing and in the reproduction of binaural artificial head signals via headphones . Frequency-weighted signals ILD = Interaural Level Difference and ITD = Interaural Time Difference are called here. These are the ear signals , as special frequency-dependent level differences, which are called spectral differences, as well as transit time differences corresponding to the ear distance ( ITD max = 0.63 ms), which are produced by a binaural artificial head through microphones in the auricles and which have to be monitored via headphones. In the English-speaking world, this headphone stereophony is unmistakably called “Binaural Recording and Reproduction” and “Stereophony” is understood to mean the usual loudspeaker stereophony.

Both procedures are opposed to each other and must be carefully distinguished.

Artificial head recordings that are played back via stereo loudspeakers and conventional stereo microphone recordings that are played back via headphones must deliver a false sound image with a change in timbre and directional mapping. It is pointless to persuade a compatibility (agreement) that does not exist here.

There have been numerous attempts with time-of-flight crosstalk compensation (crosstalk canceller) and filter equalization in order to make artificial head recordings audible for stereo loudspeaker reproduction, even if only for a relatively small listening area (transaural stereo). Conversely, there have been attempts with time-of-flight and filter equalization to make stereo microphone recordings audible for headphone playback as well, ie to eliminate "in-head localization" in particular.

The division into “space-related stereophony” and “head-related stereophony” is not very happy because all stereo listening needs our head with the ears, that is, it is head-related. We get by with the clearly distinguishable terms: “loudspeaker stereo” and “headphone stereo”.


  • Thomas Görne: Sound engineering. 1st edition, Carl Hanser Verlag, Leipzig, 2006, ISBN 3-446-40198-9
  • 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

See also

Web links