Prompt messages can be files recorded by you on your PC which are then uploaded onto the Callagenix servers. If you wish to provide messages in this format then it is best to record the files yourself off-line from the internet and then upload when you are happy. You will need a reasonable quality of microphone attached to your PC as well as a sound card capable of receiving input and recording. Although your computer will be capable of recording very high quality messages through this method, normal telephone lines are generally only capable of supporting speech at relatively low quality so you should set your recording parameters for your prompts to be: 8kHz, 8-bit mono. This will ensure the maximum quality with the minimum size. Any higher settings than this will simply be wasted upload time. To find out more about recording formats, size and quality click on Recording Formats.
If you do not have recording facilities or wish to have the recording professionally made then contact us to see how we can help you.
Audio in the computer is always in digital form. When you record audio on the computer, your sound card is what converts the sound waves to digital format, and when you play it, the sound card converts the digital signal back to analogue so that it can be played by the speakers. Most sound cards can record and play back stereo (2-channel) audio. The telephone system on a normal line only supports mono. Top
When your sound card converts audio to a digital format, it breaks the sound up into a series of 'samples', each one a discrete slice of information about the sound. The rate at which samples are taken is called the 'sampling rate'.
Each sample, in turn, has a volume (or 'amplitude'), so that when you put them all next to each other you can hear the original sound wave. This amplitude is determined by how many bits are used to describe it. The more bits that are used to describe each sample, the more possible amplitudes it has. 8-bit sound allows for each sample to have 256 possible amplitudes, 16-bit allows for 65536, and 24-bit allows for almost 16.8 million amplitudes. The telephone line only supports 8-bit amplitude (or rather the devices attached to it). Top
To most Windows users sound files are synonymous with WAV files. A WAV file is a digitized recording which has a piece of information detailing the recording/playback parameters followed by a stream of samples of sound data. When recording your prompts you should set your recording parameters (may be set when you save the file) to be 8-bit samples, 8kHz sampling rate, mono and save your file as a .WAV (or sometimes called PCM) format. You could set your parameters to higher values than this if your sound card supports it but since the standard telephone lines are unable to support higher qualities it is entirely pointless. Additionally, the higher quality the recording, the more space your recording will use. For example, a telephone-quality, 8bit, 8kHz, mono recording will use approx 600kb per minute whereas a CD-quality, 44kHz, 16-bit stereo recording will use 10Mb for the same time. Top
If you are using Microsoft Windows then you can find the standard Windows sound recorder from your Start Menu -> Program Files -> Accessories -> Entertainment. Simply connect your microphone to the sound card and press the red button on the sound recorder to record your files. Save them as 8kHz, 8-bit, mono WAV files for the reasons explained in file formats above. Top