Stereo triangle

The stereo triangle is a term used in stereo playback technology . First, this loudspeaker arrangement will have passed during the production of the sound recording and the sound mixing in the control room, which is quite crucial for the sound setting produced.

Loudspeaker placement

In studio practice, a generally accepted loudspeaker setup has been established in which the listener forms an equilateral triangle with the loudspeakers , the so-called standard stereo setup. This triangle has three equal 60 degree angles; So seen from the listener on the center line, the loudspeakers are at a sound incidence angle (sound incidence direction) of ± 30 degrees. If you want to measure the distance from the center of the loudspeaker connection line to the listener, the result is the shortening factor 0.866 from the loudspeaker base , i.e. the distance from loudspeaker to loudspeaker, i.e. the dimensions of the loudspeaker front .

There are no binding regulations for the exact dimensions for the size of the standard stereo triangle . A mean usual edge length of the triangle would be around 2.50 m for a standard stereo triangle set up in a living room. The loudspeaker base is also called the stereo base , i.e. stereo loudspeaker base or simply base width .

If a stereo recording is played back via two loudspeakers that are approximately at ear height in front of the listener, a sound field overlay occurs in the room, which creates a stereo sound impression on the center line between the loudspeakers. In the sweet spot in the middle in front of the stereo speakers, the listener should ideally be.

However, in the end, neither the equilateral triangle nor its specific side length can be justified as a meaningful "binding norm", because these considerations neither include the specific conditions of the listening room (size and reflexivity) nor the narrowness of the reverberation cone of the loudspeakers used in the same way included in a standardized manner (even if so-called “reference speakers” are used), not to mention the imponderables of the various everyday situations in which the recordings are consumed.

Directional hearing

In stereo listening , the direction of the localization of the phantom sound sources on the linear connecting line between the stereo loudspeakers (loudspeaker base) is referred to as the direction of the hearing event and is given as a percentage from the center ( center ). The speaker direction L ( Left ) or R ( Right ) is 100%. The center is 0%. Exactly the middle between L and C is HL (half left) = direction of the auditory event 50%.

With Nahfeldabhören ( Near Field Monitoring ) eavesdropping on an equilateral triangle with Stereo less than 1.50 m edge length is called. The loudspeakers are aligned precisely with the listening position (ears), whereby the maximum distance between the loudspeakers and the listening position and the boundary surfaces - i.e. the walls - must be ensured.

The stereo art two sound overlapping speakers is an unnatural effect which does not occur in nature; because for a phantom sound source in the center, in- phase and level signals come from both loudspeakers , which are superimposed on the ears.

The stereo recordings that are listened to through loudspeakers must sound quite different with headphones , because the listening conditions ( listening conditions ) are completely different . A loudspeaker covers two ears with the auricles as well as the head and the torso. A headphone shell, on the other hand, only echoes completely separately in one ear, without any effect on the auricle, head or trunk.

elevation

In stereophony , the following effect is called elevation for loudspeaker stereo listening in the stereo triangle : If you approach the front of the loudspeaker on the center line, mid-range sound sources move upwards above the loudspeaker level.

literature

Michael Dickreiter: Handbook of the recording studio technology. 6th edition. KG Saur Verlag, Munich 1997, ISBN 3-598-11320-X .
Hubert Henle: The recording studio manual. 5th edition. GC Carstensen Verlag, Munich 2001, ISBN 3-910098-19-3 .
Gustav Büscher, A. Wiegemann: Little ABC of electroacoustics. 6th edition. Franzis Verlag, Munich 1972, ISBN 3-7723-0296-3 .

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