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With this equipment we offer a product that
adapts better to the requeriments of Authorities and professionals ,
obtaining a respect to the laws without harming the commercial activity.
The result is a simple device which could please both parts with
simplicity in its control and no previous penalties for the user, .
First of all is necessary to emphasize that
is a limiter of the audio signal that it feeds the power stages, not a
simple mute by relay or steps attenuation. The regulation is made by
means of VCA´S (Voltage Controlled Amplifiers) that varies their gain
based on the signal caught by a microphone located in the room that
measures the real sound pressure level (SPL) and is shown constantly in
a remote digital display calibrated in decibels with "A " curve. This
control is automatic and smooth, imposing a maximum top but without
producing mute neither abrupt variations in the music level.
The
remote display has been arranged in a separated box from the main
equipment to be able to fix it to the more appropriate place, which
provides a permanent information of its work to the sound
equipment.operator
The control signal is compared with working
levels fitted in programmation. In the case of limitation, no matter how
much to the input signal or the amplification in power stages is
increased, the level in the room will not surpass the fixed one as
threshold. The actuation of the limiter is indicated by a series of leds
marked with 5, 10, 15 or 20 dB of attenuation. Although it does not
indicate over these amounts, the equipment will even continue limiting
if the signal is increased more than 60 dB. When the input level arises
+15 dB above nominal, the equipment indicates in display by means of a
led called AUDIO the clipping of signal to warn of the possible
distortion. In facilities where it is required to use the own audio
program as level control, we can select it in programming, leaving then
the microphone to only indicate the level and activate the alarm.
The limitation circuitry is one of the
important advantages of this equipment since its design imposes a
maximum level but without abrupt fades in the music and the usual
effects of pumping or breathing sound that we found in many limiters,
obtaining therefore a great quality in listening even with high levels
of attenuation. This avoids the tendency of many users to its
manipulation when the effects of the Limiter alter the quality of music.
In addition, it is provided with a memory that stores the last level of
attenuation when the signal of audio is interrupted, so that when
starting again itself the sound, does not have an abrupt entrance as it
happens in other similar equipment that produces a spot of high level
until it becomes to adapt at the level of attenuation previous to
mute.
You can set the global attenuation for both
channels; this way we can adapt the maximum level of the amplifying
chain with the required working level , thus avoiding to have to reduce
the difference only with the active limitation. This assures a maximum
level sound although for some reason the equipment did not limit
normally.
When the SPL is surpassed repeatedly, the
alarm function can mute the sound during a penalty time adjustable in
the programmer. Its action is indicated in display by means of a
noticeable LED ALARM and the mute by LED MUTE. This alarm causes a count
that is stored in the no-volatile memory with date and time in which it
takes place, as well as SPL then, for a later revision by the Authority.
As security against tampering, a detector
will make act the alarm if the microphone is not connected or if it
moves from original place or even it is covered in an attempt to alter
the measurement, registering the moment at which this Manipulation alarm
takes place.
All these adjustments are only possible
through an access by code in the front keyboard, that prevents any
nonauthorized manipulation. For greater security against the
manipulation, the back connections has a protector flap with seal screw.
The inlets and cables fulfill IEC Security
Standards with approvals of different international organisms. The
equipment has protective fuse with rear access.
As ideal complement for its installation and
adjust, the equipment incorpores a pink noise generator with direct
injection and front output.
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