无法更改SpeechSynthesizer对象的VoiceGender

Question

我正在尝试更改SpeechSynthesizer对象的VoiceGender：

SpeechSynthesizer synth = new SpeechSynthesizer();
synth.SelectVoiceByHints(VoiceGender.Male, VoiceAge.Adult);
synth.Speak("Hello! Why is the voice still female?");

程序编译并运行没有错误，但声音是女声。

编辑：我检查了安装的声音：

foreach (var v in synth.GetInstalledVoices().Select(v => v.VoiceInfo))
{
    Console.WriteLine("Name:{0}, Gender:{1}, Age:{2}",
    v.Description, v.Gender, v.Age);
}

返回以下内容：

Name:Microsoft Hazel Desktop - English (Great Britain), Gender:Female, Age:Adult
Name:Microsoft David Desktop - English (United States), Gender:Male, Age:Adult
Name:Microsoft Zira Desktop - English (United States), Gender:Female, Age:Adult

EDIT2：在另一台PC上测试它，程序按预期工作。