Hello, I am trying to measure the frequency response of a capacitive micromachined microphone. I am using a super tweeter as a sound source upto 40KHz, but I am also interested in the frequency response beyond the audio frequency ( possibly upto 150 KHz). Does anyone know which transducers are capable of generating low ultrasound (40~150KHz)? and Who makes them? Thank you, and have a wonderful day ____________________________________________________________________ Kyu-Tae Yoo Ph.D. candidate Cornell University Phone:530-752-2522(office) #117 Phillips Hall :530-902-5153(cell) Computer and Electrical Engineering :530-297-5153(Home) Ithaca, NY 14853-5401 eFax :509-463-1127