Recording Voice Prompts to and from your PC Sound Card
From the Engineering staff at Telecom Audio

To build professional sounding voice prompts for your voice mail system or automated attendant, you absolutely must remove the telephone handset microphone from the picture. That cheap microphone in your handset is the weakest link in the entire telephone voice path. An inexpensive dynamic microphone from Radio Shack or your computer electronics store will work just fine. Plug the microphone directly into the mic input on your sound card and you can begin recording using the software supplied with your computer. We suggest recording in mono at 8000 samples per second (8kHz sampling rate) in 16 bit PCM. This sampling rate is the same rate used throughout the telephone company. A higher sampling rate will sound better over your speakers, but it won’t give you a true representation of how intelligibility is affected by the narrow bandwidth of the phone system. The 16 bit PCM encoding however, is much better than the dynamic range of the phone system. It’s kind of like the difference between a cassette tape and a CD. It’s actually much easier for an amateur to record using full 16 bits than it is to try compromising between clipping loud passages, and recording too quiet and getting lost in the noise floor.

If your PC does not contain simple editing tools, you should consider purchasing a program like Cool Edit at www.syntrillium.com that will allow you to cut, paste, and adjust levels, even add background music.

Suggestions…
When I used to record speech files for the phone company, we would record the entire session on DAT tape, and then go back and play the tape into the PC sound card line level input. That way we always had a backup of the entire session. We put a lot of time into the script, making sure that the target word or phrase was always in a proper carrier sentence.
The recording room has a tremendous effect on voice quality as well. I suggest recording in a quiet, carpeted room, preferably with some upholstered furniture and draperies. Its good to have a couple of hard wall surfaces, but not too many. Start by clapping your hands. If the room has significant echo, try a smaller room or a room with more fabric. Also, don’t sit at a desk facing your computer monitor. The microphone will pick up your voice as it is reflected off the monitor for that “fish tank” sound.

Once the recordings are edited, you are ready to transfer them into your voice mail system. While some PC based systems and larger PBX systems may allow you to literally transfer the files into the proper folders or directories, most voice mail users will have to play the files from their sound card directly into the telephone. This is where your Telecom Audio Voice Port comes into play. Voice Port connects between the handset and the base of any telephone to allow high quality record and play between your sound card and the phone system. Simply press in the grey button on Voice Port, hit the record key on your telephone keypad and start playing the file on your PC. You can listen to the file over your telephone handset, although the handset mic will be temporarily disconnected. Play back the recorded file from your voice mail or attendant to verify recording levels. You can boost or drop the levels by adjusting the output from the sound card.