Text to Speech quality

I just bought a new computer and the text to speech doesn’t sound neither as good as my old computer. I remember changing the voice on my old computer to a better sounding one, but I don’t remember how I did it. Im using a Mac and I downloaded the enhanced version of a german voice but im not hearing it on LingQ. Im not sure how I did it last time. Anyone know how I can get a less robotic german voice?