Matching new audio to already recorded

Hello; I've recorded and edited about 2 dozen audio clips with Audition for an e-learning file.  Now the owner would like for me to add an additional slide.

When I've tried this before, I had my pc and microphone at the same settings, recorded in the same location and with the same posture.  But the audio still sounded a bit different from the pre-existing recordings.  I eventually re-recorded the entire thing so all the audio would sound consistent.

Is there a way to make a new audio clip match the tone and volume of a previously recorded audio?   I am using Auditon CC.

Thanks