|The EBS Stereo System (EBS Microphone System) is a special arrangement for the main
microphone stereophonic sound recording in equivalence stereophony - also called mixed
stereophony. Wherein the set angle of the microphones between the main axes of the microphones,
so the Axis angle α with a total of 90° is quite as large as the resulting recording area of the Stereo Recording Angle of the Microphone System, thus 90° axis angle = 90° SRA Stereo Recording Angle.
Recording area = 2 × recording angle. That means this microphone system must be arranged in such a
distance that the microphone main axes show exactly on the edges of the ensemble as sound source.
Then the music will be uniformly distributed on the speaker base and broadly played from the left to the right loudspeaker. The three letter abbriviation "EBS" shows to the lecturer "EBerhard Sengpiel".
|Through a series of practical tests students of the Tonmeister Institute of the Berlin University of the Arts
found out a stereo microphone system, which results in a fairly uniform distribution of the phantom
sound sources on the stereo speaker base as angle of incidence, at an effective recording range of the
microphone system by
θ ' = ±45° = 90°. This system was set up empirically with two small cardioid
microphones. It was found in this case, an overall axis angle with α = ±45° = 90° which is angled
outwards and has a microphone base (distance between microphones) of a = 25 cm (!). For the chosen
word"axis angle" we find in the literature opening angle, offset angle, and receiving angles, which can
be partially mixed with SRA = Stereo Recording angle and which often represent only half the angle.
The sometimes cited ear distance of the human head is in stereophony of no matter, because this distance has absolutely no relevance to the loudspeaker signals.
In the formation of the respective frequency-neutral direction of listening the interchannel level differences Δ L and in the the same sense acting interchannel time differences Δ t act together as loudspeaker signals. This recording technique is called mixed stereo or equivalence stereophony.
Thus simultaneously the intensity stereophony and the time-of-arrival stereophony is applied. This signal differences is denoted by the word equivalence.
Usually, the sound engineer must compose the special microphone system of two single-miniature microphones. Large double-diaphragm microphones should be avoided because of their unbalanced directional characteristics and the larger phase transitions. It seems advisable to experiment with the two parameters, the axis angleα for Δ L and the microphone base forΔ t.
A sound recording with a main microphone system is often supplemented by additional spot or support microphones.
"Visualization of EBS Stereo microphone system - cardioid/cardioid - α ±45° = 90° -
microphone spacing a = 25 cm":
"Comparison of some equivalence microphone systems - ORTF - NOS - EBS (German)":
"The Stereo Recording Angle SRA of stereo microphone systems (arrays) with two microphones":
"Richtungslokalisation bei Stereo-Lautsprecherwiedergabe in Abhängigkeit vom Schalleinfallswinkel auf das Mikrofonsystem − Äquivalenz-Stereofonie - Gemischte Stereofonie)
Beispiel: EBS-Stereosystem, Richtcharakteristik Niere/Niere, Achsenwinkel α = ±45° = 90°, Mikrofonbasis a = 25 cm. Aufnahmebereich = Achsenwinkel":
"Der 'magische' Aufnahmebereich? ... oder eher der unverstandene Aufnahmewinkel von Mikrofonsystemen (Stereomikrofonen) in der Tontechnik":
"Equivalence Stereo (cardioids) 3 - SRA for microphone systems with two cardioids":
"5 Richtungslokalisation bei Stereo-Lautsprecherwiedergabe in Abhängigkeit vom Schalleinfallswinkel auf das EBS-Mikrofonsystem - Äquivalenz-Stereofonie (Gemischte Stereofonie)":