Tri-Amping - A technique commonly used in large-scale sound amplification for concerts, Tri-amping is the practice of connecting three audio amplifiers to a loudspeaker unit: one to power the bass driver (woofer), one to power the mid-range and the third to power the treble driver (tweeter).
Keith Briffa, from the University of East Anglia's Climatic Research Unit, said the tropical ocean regions were among the more reliable areas from which to infer large-scale temperature changes.