Behringer XR4400 +

MULTIGATE PRO XR4400

+The following operational manual will introduce you to the BEHRINGER MULTIGATE PRO and

its various functions. After reading the manual carefully, make sure it is always on hand for

future reference.

By employing current modern analog technology it is possible to manufacture audio equipment with a dynamic

range of up to 130 dB. In contrast to analog techniques, the dynamic range of digital equipment is approxi-

mately 25 dB less. With conventional record and tape recorder technology, as well as broadcasting, this value

is further reduced. Generally, dynamic restrictions are due to noisy storage in transmission media and also the

maximum headroom of these systems.

1.1.1 Noise as a physical phenomenon

All electrical components produce a certain level of inherent noise. Current flowing through a conductor leads

to uncontrolled random electron movements. For statistical reasons, this produces frequencies within the

whole audio spectrum. If these currents are highly amplified, the result will be perceived as noise. Since all

frequencies are equally affected, we term this white noise. It is fairly obvious that electronics cannot function

without components. Even if special low-noise components are used, a certain degree of basic noise cannot

be avoided.

This effect is similar when replaying a tape. The non-directional magnetic particles passing the replay head can

also cause uncontrolled currents and voltages. The resulting sound of the various frequencies is heard as

noise. Even the best possible tape biasing can only provide signal-to-noise ratios of about 70 dB, which is not

acceptable today since the demands of listeners have increased. Due to the laws of physics, improving the

design of the magnetic carrier is impossible using conventional means.

1.1.2 What are audio dynamics?

A remarkable feature of the human ear is that it can detect the most wide ranging amplitude changesfrom the

slightest whisper to the deafening roar of a jet-plane. If one tried to record or reproduce this wide spectrum of

sound with the help of amplifiers, cassette recorders, records or even digital recorders (CD, DAT etc.), one

would immediately be restricted by the physical limitations of electronic and acoustic sound reproduction

technology.

The usable dynamic range of electro-acoustic equipment is limited as much at the low end as at the high end.

The thermal noise of the electrons in the components results in an audible basic noise floor and thus repre-

sents the bottom limit of the transmission range. The upper limit is determined by the levels of the internal

operating voltages; if they are exceeded, audible signal distortion is the result. Although in theory, the usable

dynamic range sits between these two limits, it is considerably smaller in practice, since a certain reserve

must be maintained to avoid distortion of the audio signal if sudden level peaks occur. Technically speaking,

we refer to this reserve as headroomusually this is about 10 - 20 dB. A reduction of the operating level would

allow for greater headroom, i.e. the risk of signal distortion due to level peaks would be reduced. However, at

the same time, the basic noise floor of the program material would be increased considerably.

1. INTRODUCTION