This is the medical device : http://www.dymedso.ca/site_usa/patient/en/frequencer_v2_easy_to_use.htm You can hear what it sounds like here : This paper describes how it works (Page 10) : http://www.dymedso.ca/pdf/White paper_rev0_Sept20_041.pdf The above document contains a lot of valuable information and some math regarding how the Frequencer works (page 19). The device uses sound waves to create vibrations inside the patient's chest to help dislodge thick mucus. I need a driver that can generate frequencies between 20Hz and 65Hz. It has to be around 6 inches and not too heavy. From the little that I understand about speakers, this seems like a tall order. How can I achieve this? Thanks for your help. Edit : Really? Is no one willing to assist with this? Not even point me in the right direction? Replicating this device is 100% safe and even if there was any risk involved, I am an adult and I am able to make my own decisions with regards to my health. Holding back from helping me out of some unfounded concern for my health is the opposite of helping me. As it stands right now, I am looking at possibly having to get on supplemental oxygen 24/7 unless I can find a way to improve my lung clearance. In other words, I'm dying. It can't get worse than that.