Points out that many mechanical engineers are not familiar with silencer developments beyond standard dissipative silencers for air handling systems in the form of rectangular (straight and elbow) and circular (cylindrical and cone) silencers that are common in the HVAC industry. Maintains that learning about other available silencer solutions could solve many common problems, including space congestion with resulting system effects, high velocities and excessive energy consumption, low frequency noise, indoor air contamination and total cost. Goes on to describe for those in the HVAC industry the progress being made in silencer designs and applications and explores practical solutions available to solve today's noise control problems. Concludes that striving for better aerodynamics and lower pressure drops provides the biggest opportunity for overall improvement.