Not sure how the father voice fits into the picture, but I'm convinced that for many it's the stronger voice. At least equally as strong. I think his voice often gets minimized in the mental health arena.
Perhaps thanks to Freud, all of our failures are heaped onto our mother's failures. Thanks to our society, the tendency has been to heap all of our successes onto our father. I'm not the first to see that as a very unhealthy split, and splitting isn't a good sign in people or in professions or institutions.
Look at how it works with abuse. We recognize the physical and sexual abuse as a problem that is more likely to be perpetrated by fathers. Yet what about the voice of the perpetrator--our focus seems to be more on the acts, rather than the words or attitudes.
Our fathers have just as much potential to influence us in positive ways, depending upon how much they were in our lives. Just as much as our mothers. And just as likely to be negative forces, as well.
Try listening to how often the voices of both parents play in your head. Compare the volume now with long ago. Keep what's good. Nurture it. And join me in throwing out the garbage.