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Precision Power (or simply PPI as it is known throughout the industry) was famous for stunning amplifiers during the nineties. Shooting to fame with the release of the ‘Art’ series amplifiers, then backing this achievement up with the ‘Powerclass’ range of amplifiers, it seemed PPI could do no wrong. Soon after, it began delving into the speaker and subwoofer market. Now these components were very well designed and constructed from quality materials but didn’t quite receive the glowing reception the amplifiers did. And so for years PPI has dealt with having a reputation for producing brilliant amplifiers but speakers that struggle to match. Well this latest offering from the American giant might just change all that.
THE POWER OF PRECISION
The 356CS component set landed in our offices recently, and after a few days of listening, we
were very impressed to say the least. Based on the world renowned a/d/s component design, the 356CS is the larger brother of the series (there is a 355CS 5.25-inch component set available too) and are closer to the 6-inch mark rather than the 6.5-inch. They come neatly packaged in a very colourful red box which includes the two woofers, two tweeters, two crossovers and a heap of mounting hardware including cables. At first glance the crossovers look tiny but upon closer inspection you soon realize that only the terminal blocks are poking through the packaging box – the much larger body of the crossovers is nearly triple the size than originally suspected.
The cone itself is quite an interesting blend of materials; its base is an interlaced Aramid fibre (fancy term for Kevlar) blended with Mica and fibre-glass for strength. Laid on top of this extremely stiff under-layer is an IMPP (injection molded poly-propylene) surface. This blend equates to a cone that has exceptional strength and very low physical distortion (the instructions even go so far as to say ‘ultra-low’!). Located in the center of the cone is a bullet shaped phase plug surrounded by a felt ring, both of which assist with the dispersion characteristics of the sound throughout the audible range. This plug can be unscrewed and an adjustable angle tweeter mount screwed in its place if you want to use the set in a co-axial arrangement instead. The remainder of the driver, save the magnet and voice coil, is constructed from industrial strength plastic and the basket has twelve fingers holding the cone support to the motor cup.
The voice coil is aluminium and is wrapped in copper clad alloy wire. Cooling is one thing that always catches my attention and PPI claim the woofer has advanced vent construction. Now call me picky but I could not see any vents at all in the perimeter of the basket. Sure, the voice coil former itself has exceptional cooling attributes, but if you cannot get copious amounts of air in there in the first place then why bother? The flat poly-cotton spider between the magnet and frame works well in conjunction with the butyl rubber surround in keeping the internals aligned. The magnet itself is quite large and is also encased in the plastic frame. Despite this, the mounting depth stays at a modest 62mm. The metal grub screw type terminals are built into one of the frame fingers and are also totally surrounded by plastic. It feels like a robust unit and you would get a few drops before you did any real damage (although I wasn’t about to test this).
Moving along to the tweeter, again I found the construction and material quality to be of a very high standard. The dome itself measures 25mm and is made from silk. This is then coated with a light weight polymer coating to allow the dome to maintain its shape even under extremely fast transients. The resulting sound is detailed and crisp thanks to a perfect ratio between strength and mass. The overall linearity of the tweeter is very good although it did have a little dip around 6000Hz and a high peak around 13000Hz according to our AudioControl RTA. The voice coil design of the tweeter is similar to the woofer with a copper coated silver wire wound on an alloy former. Cooling is handled by ferro-fluid and the tweeter has a long excursion, meaning it suffers less from overruns if it’s pushed a little too hard.
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