Some of the details of the birth of the Bullsh*t slogan are still to be uncovered.  However, Bob Moers was present, and according to his recollections (2009 recorded interview) it came about as follows:

In the 1960’s Bob replaced PWK’s longtime ad agency (Goodloe Stuck) with a Chicago firm. Of note, this agency had a famous air-brush artist known for cleaning up photographs of hams for the Chicago meat industry, as well as “taking warts off” of Playboy bunnies. 

“Bill” of this agency was in the office with PWK when he threw a hi-fi magazine he had been reading up into the air and screamed “Bullsh*t!” The article was about the AR-3A. By this point in time PWK had become thoroughly disgusted with loudspeaker advertisements claiming “another major breakthrough." Not only did our “Bullsh*t” slogan result, but the ad/pamphlet “Ho Hum Another Major Breakthrough” was born. 

In 1975 the famous bullsh*t T-shirt debuted. All employees received one for a photo shoot in front of the shipping dock. Only Bob Moers put his back to the camera for obvious reasons. Soon a University of Arkansas student was kicked out of class for wearing the audacious shirt.

Klipsch & Associates paid for his legal counsel.