While re-perusing an old article to answer a question on another list, I noticed something about coanda nozzles that might be of interest to rotary fans. It mentions that while there is no performance increase, it does seem to 'mellow' the exhaust sound. I wonder if this might survive the rotary pulses better than other pulse breaking techniques & help take the edge off the rotary bark. (Although it might be a moot point if everyone adopts Dennis Haverlauh's system for the Renesis.)

http://cafefoundation.org/v2/pdf_cafe_reports/EPG%20PART%20IV.pdf

Charlie