Question:

I decided to try some recordings and although I have 30 years of experience recording audio in the music industry and can produce beautiful recordings, when your software plays them, they are muffled and low volume.

My audio files are fine. They are wave files recorded at 8K 16 mono, as prescribed. They sound terrible when your system call out, but the built-in voice that states the time and date of the appointment, as well as the persons name, sounds perfect.

Answer:

If the system sample audio files play OK, that means the software, modem, and your phone lines are all OK.

To produce the same quality audio recording, you have to use a professional recording studio, where background noise is almost eliminated. Second, you have to record your voice with a large volume. The recording using a microphone and play over the computer speak is very different from recording and playing over the phone line.

In terms of audio recordings, please see Audio quality FAQ

Follow up:

That worked. I had to set the volume at 500%, but it sounds good.