Installation manual

Community S-Series - Operation and Installation Manual - Page 18
COOL-COIL™ TECHNOLOGY
The cone drivers used in the S-Series 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 5 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 for the voice coil, and the airflow director causes
the air to pass in close proximity to the former. By directing the air to flow over the hot
aluminum former, more heat is removed from the voice coil than simply allowing the
pumped air to take its natural path in and out of the cavity. This results in woofers that can
handle higher power with greater reliability than those of conventional design.
Figure 5: Community’s Cool-Coil™ Heat Evacuation System
OPERATING IN PASSIVE OR BI-AMPED MODE
All S-Series full-range loudspeaker models may be operated in either the passive mode or
the bi-amped mode.
A switch on the full-range loudspeaker input panel selects between the two operating
modes: PASSIVE mode (single amplifier) or BI-AMP mode (separate low and high frequency
amplifiers). In both PASSIVE and BIAMP mode, the internal crossover divides the audio
signal into the separate frequency ranges for each of the drivers.