Nilfisk-ALTO ACL2 Pro Air Compressor User Manual


 
1. INTRODUCTION
You are now the Owner of an LTO ACL2 PRO Compressor/Limiter/Gate. The ACL2 PRO is a very powerful dynamic
processor. We have included in it with several innovative circuit designs that make the ACL2 PRO a very versatile
processor: smart and fast recognition of the program, adjustable Expander/Gate and very low distortion Voltage Control
Amplifier (VCA).
Feature List:
Smart Knee Control Compressor (SKC)
Soft knee or hard knee? This is the question! SKC combines both: In the "soft knee" mode you control the program
material so that the compression will be the most musical and inaudible. On the other end, the hard knee function
is used for better precision, limiting signal peaks with precision and will allow you to add creativity to the dynamic
processing. This function also allows you to protect other equipment in the signal loop against distortion.
The AUTO Function
Your ACL2 PRO includes AUTO function switch on the front panel. Thanks to the AUTO function attack and release
times of the program materials are automatically analysed. Then the dynamic range of the program is heavily
compressed in a very musical way so that there will not be any audible breathing or pumping effect.
Attack and Release Controls:
Ok,Ok, you do not want to get advantage of our AUTO function and be the Master of your own mix.
We have provided your with User Adjustable attack and release time for the best total manual control.ACL2 PRO
Smart Ratio Control expander (SRC)
During music pauses or when a quiet session occurs, the noise floor maybe highly amplified and this effect may
be exaggerated because of inappropriate use of the expansion ratio. The SRC control will adjust the expansion
depending on the input signal so that those signals, which are slightly above the noise floor level, will get the major
benefits.
Smart Gain Control peak limiter (SGC)
This function includes two important functions: Clipper and program limiter. The peak limiter will be activated above
a certain threshold that is adjusted by the User and will radically restrict signal peaks. But what about if the threshold
of the Limiter is surpassed only for a few milliseconds? SGC will turn on automatically and reduce theoutput signal
so that you will not hear any distortion. Smart, isn't it? The SGC proves to be very efficient in loud-speaker protection
and to reduce undesired peaks in digital situations.
2. THE CONCEPT BEHIND
2.1 Some technical stuff
Good old analog technology: It will allow us to manufacture audio equipment with a very high dynamic range: up
to 125 dB. But the dynamic range of digital equipment is more or less 25 dB. A further reduction in dynamic range
occurs with the use of tape recorders and/or vinyl records.
2.1.1 It is not just Music
Yes, a piece of electronic will produce some noise. When the current flows through a conductor this will
generate a certain movement of the electrons and therefore: noise. And throughout the whole spectrum of
audio. Imagine what happens when this inherent noise will be amplified. Yes, today one can use "low-noise"
components but still such components will present a certain level of residual noise.
4
For example with tape recorders it will not be possible to get an S/N (signal to noise) ratio better than 70dB.
This level would not be accepted today by the increased sensitivity of the listeners. It is possible to improve
the performance of a tape recorder: Absolutely no!