For instance, a speaker with a woofer and a tweeter is 2-way. Such tweeters are called a "plasma" tweeter or "ion" tweeter. The efficient SM (Studio Monitor) series incorporated a polycell tweeter and graphite impregnated midrange/woofers. A rigid construction is necessary to optimize the working environment for both woofers and tweeter. The original midrange and tweeter cones were paper. All of the models cited above feature separate horn-loaded tweeter and midrange. An inverted dome tweeter was designed and developed by Focal in 1981. Specifically, the T27 was replaced by a 19mm doped fabric dome tweeter. Hz, a free-air mounted tweeter and 500 watt RMS power handling. Rear wave of the tweeter is gradually absorbed to reduce distortion. It enabled Focal to develop a lighter and faster tweeter which provides excellent damping qualities. The NS-10M X is a "Studio" with magnetic shielding and a different tweeter. It additionally incorporates a two way design by its inclusion of a dedicated tweeter/supertweeter panel. The MB-80 employed tweeter clipping protection and indication. As tweeter technology has advanced, different design applications have become popular.