I imported audio into Audition. In Audition, I created waveform and time-varying spectral displays. With Snagit, I video-captured the waveform and spectral display as MP4. Saved it. Imported it to After Effects. No audio.
It appers that you have found the problem (so thanks) but I still don't understand the solution. I thought the sound just came along with the MP4. Can you guide me further? Meanwhile, I will peruse the Adobe book on AE.