The voice of your Higher Self manifests in many different forms - you don't need to worry about the way it sounds too much. (Unless it starts growling at you or something
It also helps not to be too attached to where it's coming from. For example, I often hear the voice of my HS in people around me - I have overheard strangers saying exactly the message I needed to hear in response to a question I asked my HS/Guides like the day before. And ended up overhearing the exact same message again from a different stranger.
So, guidance doesn't always have to be directly from guides or your HS or in 'their' voice. It's everywhere, in fact.