Happy new year!  It is 2011. 

Recently I got a customer question regarding "SupportedAudioFormats".  He used the Server Speech Platform 10.2. But he found the SupportedAudioFormats of speechsynthesizer is empty.
This is because of some issue in service voice setup. All the service voices currently is in 8k8bit PCM format.

The voice audio format can be specified like below.
speechSynthesizer. SetOutputToWaveFile(“output.wav”, new SpeechAudioFormatInfo(8000, AudioBitsPerSample.Eight, AudioChannel.mono));

if you set audio format to other format like 16k16bit, the speech synthesizer will do resampling for you.