17,1 iMac 10.14.2, 24gb ram, I have used the Mac for 20+ years, and still do not understand how to differentiate when setting up a tape player to record, or apps that need sound input to analyze. I have an app in Mojave that can analyze sounds and display results, but the sound needs to be sent into the app. I am told to use a microphone in front of a speaker, but how does the sound get into the app from the microphone. I have a Griffin iMic I have used to record tapes played into the Mac, but playing into the app? What exactly is sound input and sound output, or how to think about input output for this sound analyzing app? Why doesn't this app analyze from the sound out? Like I know what I am talking about.