Cool-Coil™ Technology - Community VERIS 2 Operation Manual

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 simply
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 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 third 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 period of 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.
COOL-COIL™ TECHNOLOGY
The cone drivers used in the VERIS 2 subwoofers utilize Community's patented Cool-Coil™
heat evacuation technology. A proprietary process, Cool-Coil employs an airflow director to
remove heat from the voice coil, thereby increasing both the performance and reliability of the
cone drivers. In particular, the effect of Power Compression is significantly improved by Cool-
Coil technology. Power Compression occurs when drivers respond non-linearly to applied
power, producing less and less output as their voice coils heat up and their impedance rises.
High voice coil temperatures have other undesirable effects on performance. Most materials
used in drivers, particularly adhesives and insulation, suffer some diminished properties under
extremes of heat. Thermal expansion can result in warpage and misalignment of components.
A voice coil in which the diameter has increased due to thermal expansion will often no longer
be round, and certainly has a greater possibility of rubbing against the magnetic structure.
Any amount of cooling that can be applied to a woofer will be beneficial. One very commonly
used cooling method is venting of the pole piece of the magnet structure. The motion of the
cone assembly will pump air in and out of the cavity under the dust cap. This air passing
through the pole vent helps to cool the magnet structure. Community has improved on this
common cooling method by introducing an airflow director (US patent 6,390,231) into the air
path. Figure 3 shows a conventional woofer motor with a vented pole piece, and also a similar
motor with the addition of an airflow director. The voice coil former in the airflow motor is
aluminum, and is taller than normal. This extended aluminum former becomes a cooling fin
VERIS 2 – Operation Manual - Page 14