Audio Production Tips

Angel.com allows you to quickly build a Voice Site using text-to-speech. It's simple: you type the text for each Voice Page, and Angel will play it back to callers. For a more sophisticated caller experience use recordings of your own voice (or voice talent). Angel offers two methods of sound prompt recording.

Recording Over the Phone
If you don't have the equipment, or you're on the road, Angel.com offers an easy way to record your Voice Site over the phone. Simply call your Angel Number, go to the Voice Page you want to record and say "Record". The system will give you step by step instructions to complete the process. To record other pages, just visit them and say "Record" again.

Uploading Sound Files From Your Computer
With a little time you can improve the quality and timing of your sound files dramatically. With a simple recording program and a microphone, your computer can become a full-fledged recording studio. See below for technical details.

Once you have your sound files, use Site Builder to incorporate them to your Voice Site. On each page, convert a text prompt into an audio prompt first, by clicking the arrow icon. Then, click on the "Link Audio" button.

Getting the Most Out of Your Recordings
When recording time comes, there are a few things to keep in mind.

Find a quiet room where you can place a computer with a quality microphone to do the recording.
Spend a little time playing with the recording levels of your microphone and your computer. It sometimes helps to upload a sound file to Angel and call in to hear the result firsthand.
If you want simple recordings, record directly at 8Khz, 16-bit, mono, Windows PCM .wav. This will save you the downsampling process.
Trim the beginning and end of your sound prompts. Silence at the end of a sound file can confuse your callers and prompt them to speak at the wrong time. Trimmed sound files make your caller experience more snappy.
You can use Windows Recorder, or try one of many available sound recording programs such as GoldWave.

Best Sound File Format
The best type of file to upload for playback by Angel.com is Windows PCM Wav, 8 kHz, 16 bit, mono. When Angel records a file for you through a voicemail page, it is recorded as a ADPCM u-law, 8kHz, 8 bit, mono. Most WAV files are PCM, which essentially stores the amplitude of the sound file in each byte. But WAV files can also be u-law (pronounced mew-law) which is ADPCM. At a high level the difference is that PCM files segments off the sound file and stores the amplitude in each byte. ADPCM stores off the difference in amplitude. This has implications for things like concatenation.

Upgrading to Professional Voice Talent
Angel.com works with several voice talent agencies that can help you identify the right voice for your Site. You can also listen to some of the voices on one of our partner's websites.

Sound Search Engines
Angel can also play soundmarks, earcons, music and other non-speech audio prompts. Thoughtfully used, these can improve the navigation of your Voice Site and further define a sense of persona.

The Web has several sources of audio sounds:

Recommended Audio Tools
Angel.com recommends the following audio tools:

Sound problems?
If you're having trouble with a specific sound file, submit a ticket in our Support Center and we will work with you to solve it.