Lori,
Here is the link to the thread I started last March. It includes a lot of information on the Model Talker.
assistive technology clinic (voice banking)
The headset microphone is a must, Your husband knowing up front it can be tedious and some sounds/words he attempts are going to keep getting rejected by the program (it happens to everyone) will perhaps help stave off frustration. I found that if I couldn't get a particular recording to take, after a couple of tries, I'd just go back to it later.
Earlier in the morning and/or when most rested is best time to work on making the recordings.
At the time I did this, I was still living in the city, so I did take steps to soundproof the room I did it in, mainly just draped as much sound absorbent material around the room as I could. ... quilts, blankets on walls and over windows. Bedrooms seem to be a natural "sound studio" because the bed helps soak up ambient noise, also carpeting helps.