Installation manual

Community S-Series - Operation and Installation Manual - Page 15
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 an additional stage of protection will engage that shuts down
the system entirely (note that 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 merely reducing the drive level to the system.
Advantages of Community’s DYNA-TECH Circuitry
There are numerous advantages to this type of multi-stage protection circuitry. The trip
point is pre-set to engage at exactly the same time on all speakers that are powered from
the same amplifier. The initial stages of DYNA-TECH protection circuitry do not rely on, and
are not affected by heat build-up. Some manufacturers use circuit breakers that require
heat build-up before they trip; this limits their ability to protect a cold speaker. The trip
points of such breakers are also affected by ambient temperature, their own internal
heating curves, and small variations in speaker 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 excessive increases in level.
Moreover, the protection disengages almost immediately when the level 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 excessive musical peaks, without
fear of damaging 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 an additional level of protection for
the entire loudspeaker to guard it from severe misuse. If the system is operated in the
second-stage protection mode for a long period of time, or if the input level is increased by
someone trying to overcome the volume drop from the second-stage protection circuit, 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.
HIGH-FREQUENCY PRESENCE SWITCH
Each S-Series full-range loudspeaker is equipped with a Presence Switch on its rear input
panel. This switch selects between two different high-frequency contours to adjust the
voicing of the loudspeaker. Using the Presence Switch allows you to optimize the audio
quality for different performers, for varying types of program material, and for differing
acoustical environments.
One position of the Presence Switch is labeled MUSIC (FLAT) while the other position is
labeled VOICE-SPEECH (+4dB). In the MUSIC (Flat) position, the response of the
system is essentially flat; in other words it will exhibit no significant variation in amplitude
throughout its operating range. In the VOICE-SPEECH (+4dB) position, the mid band
between approximately 2 – 4.5 kHz is accentuated by approximately +4dB for increased
articulation in the vocal range, with less accentuation extending from approximately 1 kHz
to 8 kHz.