Community ENTASYS, Руководство по установке и эксплуатации

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Community ENTASYS Installation/Operation Manual — Page 13
DYNA-TECH
TM
Driver Protection Circuitry
DYNA-TECH and DYNA-TECH Plus are multiple stage protection mechanisms that trigger on different
aspects of the input signal. The first stage is dedicated to the high frequency drivers. It will not allow the voltage
delivered to the input terminals of the Compact Ribbon Emulator (CRE) devices to exceed their maximum input
rating. If this voltage rating is exceeded, a hard limiter engages to clamp the voltage at this threshold.
The second stage of the circuit protects all the drivers in the system. This stage is based on an electro-
mechanical relay driven through a voltage sensing circuit. The relay engages at a predetermined voltage,
corresponding to an input level that would otherwise cause driver damage. When engaged, the relay introduces
a bank of high-wattage resistors in series with the drivers. These resistors cause a voltage drop in the signal to
the drivers, thereby reducing the power applied to them. When the relay protection circuit is activated, there will
be a noticeable drop in the system’s level (approximately 3 to 4 dB). This serves as a warning to the operator
that the loudspeaker is being overdriven. When this stage of protection is engaged, the level of the console and/
or the amplifier’s output to the loudspeaker system should be reduced.
IMPORTANT : If the operator continues to run the system at excessive levels, or worse, if the operator
raises the drive level to compensate for the drop in output caused by the protection circuitry, eventually a
third stage of protection will engage that shuts down the loudspeaker system entirely. This additional
stage of protection will never engage until after the second stage has been triggered. If the system
shuts down entirely, the operator can immediately restore sound by simply reducing the drive level to the
system.
The only difference between DYNA-TECH and DYNA-TECH Plus is in the first stage, high frequency
protection. This is unique to DYNA-TECH Plus and is used on full-range and high frequency loudspeaker
systems. Loudspeaker systems that do not employ high frequency drivers use DYNA-TECH.
Advantages of Community’s DYNA-TECH Circuitry
There are numerous advantages to this type of multi-stage protection circuitry. The trip point is preset to
engage at exactly the same time on all loudspeakers that are powered from the same amplifier channel. The
initial stages of DYNA-TECH protection circuitry do not rely on, and are not affected by heat buildup. Some
manufacturers use circuit breakers that require heat buildup before they trip. This limits their ability to protect a
cold loudspeaker. The trip points of such breakers are also affected by ambient temperature, their own internal
heating curves and small variations in loudspeaker impedance or crossover component tolerances, all of which
can cause unpredictable behavior. Because the first and second stages of Community’s DYNA-TECH circuits
are not thermally sensitive, they react nearly instantaneously to protect against an excessive increase in level.
Moreover, the protection disengages almost immediately when the drive level to the system is reduced. It is not
necessary to wait for a circuit breaker to cool down. This means that your loudspeaker can operate at its full
dynamic range and still react quickly to protect against excessive musical peaks, avoiding damage to the
system. It also means that your loudspeaker is protected from the moment the power amplifier is plugged in and
turned on, regardless of the ambient temperature.
As mentioned above, the protection circuitry provides a final level of protection for the entire loudspeaker
to guard it from severe misuse. If the system is operated in the second stage mode of protection for a long
time, or if the input level is increased to try to overcome the volume drop from the second stage protection
circuitry, a solid-state circuit breaker will trip and remove all signal from the loudspeaker until the input level is
reduced. Because this circuit breaker is heat sensitive; it provides a final level of protection that takes heat into
account as well as power. However, unlike most implementations of circuit breakers that take time to cool down
before resetting, DYNA-TECH circuits respond instantly to a reduction in level, restoring the system to its full
dynamic range without needing to wait for the circuit breaker to reset itself.
INTRODUCTION