If you don’t have a Mac you can still easily record audio from and online text to speech generator to get that Siri voice. In fact, many of these online text to speech generators have access to many of the exact Siri voices.

TTSReader is one of these options. The default automated voice option is ‘ENGLISH, UK, DANIEL’ which is the same voice Siri uses by default on UK Macs and iPhones. If you want to use the Siri voice that comes as default on US devices simply find ‘ENGLISH, US, SAMANTHA’ in the voices drop down menu.