A year before, Google introduced an app named as the Voice I of Google Assistant that featured a robotic voice similar to female’s voice. But, from today, you have an option to choose among the two voices i.e the previous voice or a similar male robotic voice. Google dubbed this new feature as Voice II.
You can access this new feature from Assistant on Google Home and on phones. It is very easy to set a male voice. For that you need to simply go to Settings >Preferences > Assistant Voice on your phone Assistant or Google Home app.
You will have only single Assistant on all the devices as the settings done are between the Home app and on-device Assistant.
The new voice will be made available for everyone provided that all your Google and Google Home apps are updated.
Source: Android Police