Your voice is fine. Your delivery could use a lot of work. You could do with mixing your clips a little better and possibly getting a better mic. There's some crackling going on as you record. Something like Mixcraft or Audacity FX, compression especially, could really bring out what you have to offer. I find your normal voice pretty okay for narrating. Would just be better scripted so you actually know what you're doing and present that to your audience. A demo reel needs to be concise!