Configuring Text to Speech

Only the Trial and Enterprise versions of VoiceGuide support Text to Speech (TTS).
The Personal and Professional versions of VoiceGuide do not support TTS. 


VoiceGuide can use SAPI compatible TTS engines, and a range of other TTS engines for which MRCPv1, MRCPv2 and native integrations are available.

Please contact to discuss which TTS engine would best suit your requirements.


VoiceGuide v7



To use MRCP/MRCPv2 TTS engines the VG.INI [TTS] EngineType entry must be set to:


Other required settings are MRCP_Profile and MRCP_Language

The MRCP Profile and Language etc can be dynamically set during the call, by setting new values to $RVs:


Please contact VoiceGuide for detailed instructions on setting up MRCP based TTS engines and profiles.



To use SAPI TTS engine the VG.INI [TTS] EngineType entry must be set to:


The SAPI_Engine entry then must be set to the SAPI TTS Engine to use. eg:

SAPI_Engine=Cepstral Allison-8kHz

The list of TTS engine names that are installed on the system can be obtained from the VoiceGuide ktTts trace log file. At the beginning of the trace file there will be a section that lists all SAPI engines installed on the system. That section looks something like this:

124244.953 2812 tts voice 0 : Microsoft Mary
124244.953 2812 tts voice 1 : Microsoft Mike
124244.953 2812 tts voice 2 : Microsoft Sam
124244.953 2812 tts voice 3 : Cepstral Allison-8kHz
124244.953 2812 tts voice 4 : Sample TTS Voice

The name of the engine is listed after the "tts voice X : " tag.
The example listing above shows that the following TTS engines are installed on the system:

Microsoft Mary
Microsoft Mike
Microsoft Sam
Cepstral Allison-8kHz
Sample TTS Voice

so any of the above can be specified as the value of the SAPI_Engine entry in the VG.INI file.


Format of the WAV file which the SAPI TTS engine should generate can be set in VG.INI, section [TTS], field SpStreamFormat. eg:


The above "8khz8" entry is used to request that SAPI TTS generates 8kHz 8-bit PCM WAV files.
Other possible settings are:



The TTS Engine Type can also be dynamically set during the script, by setting new values to $RV:


This allows the script to dynamically select which MRCP or SAPI or Native TTS engine should be used at any time during the call.


VoiceGuide v6 / v5

Default SAPI TTS voice can be set using the Speech applet from the Windows Control Panel:

If the Speech applet show above cannot be seen in the Control Panel then it can be found in this location:
C:\Program Files\Common Files\Microsoft Shared\Speech\sapi.cpl

We have received reports that selecting the default TTS engine using the Control Panel's Speech applet does not work on some systems. In these situations we'd recommend moving to VoiceGuide v7. VoiceGuide v7 sets the TTS engine internally.


Installing and Testing SAPI TTS Engines

Installation of Microsoft's SAPI 5.1 SDK is recommended to allow testing of SAPI TTS engines.

SAPI requires that a sound card is present in the system in order to operate properly.

To test if the SAPI TTS engine installation completed correctly the SAPI SDK's TTSApp program can be used:

Start -> Programs -> Microsoft Speech SDK 5.1 -> Tools -> TTSApp

Then select the TTS engine and press the "Save to .wav" button. If the .WAV file was created and you can play it back using a sound file player then the SAPI TTS engine is properly installed.