 Woodworth, W8AHW began experimenting with different types of microphones for their "ham" stations.Their mutual friend, Charles Semple, worked for Brush Development Company where he had been experimenting with Rochelle salt crystals.Semple demonstrated some crystal pick-ups that Brush was working with, leading Chorpening and Woodworth to found The Astatic Microphone Laboratory, Inc. in Youngstown, Ohio in 1933.