Description

Automix algorithm

The unit's automix algorithm has 3 basic functions which assess the amount by which an

 

input signal is to be attenuated and the output signal's output level. The following functions

 

and parameters flow into the automix algorithm:

 

Dynamic level adjustment

 

The master of all input channels is determined on an ongoing basis. This value is used as the

 

reference value. If the input channel level is very close or over the reference value, this

 

channel will be assessed as dominant and will be slightly attenuated. If the input channel level

 

is well below the reference value, this is assessed as ambient noise and be severely

 

attenuated.

 

A channel's output level is calculated using the following formula:

 

Output level = Input level - (Reference value - Input level)

 

This formula ensures that the output level will not become louder if several input channels are

 

active, rather the master assumes the level of a single channel. This reduces the risk of

 

feedback.

 

If a channel is no longer assessed as dominant, this falls at 1 dB/second and all other non-

 

dominant channels increase with the same constant so that the master output level remains

 

constant. The upward adjustment of a channel takes between 3 ms and 5 ms.

 

Best Mic On

 

With two microphones that are positioned close together there is the disadvantage that comb

 

filter effects may arise by cancelling the frequency components. To suppress these unnaturally

 

muffled or hollow signals, only the microphone channel with the highest level is assessed as

 

dominant and switched on.

 

Noise Detect

 

Permanently present interfering signals, whose amplitude are large enough to be assessed as

 

dominant, but whose level and frequency changes are too low, are not assessed as dominant.

 

Interfering signals such as noise from fans and air-conditioning units are recognised and not

 

used as activation criteria for microphone channels.

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DMM 12BC

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AKG Acoustics DMM 12BC manual Description Automix algorithm, Dynamic level adjustment