Sorry for being so forward, but dare I say that wanting a slower speed is perhaps a sign of laziness. And here’s why…
We have the pinyin guide; so pronunciation can be learned. We have the lesson; so the sentences are presented in a clear and slow way. We have the written dialogue; so we can read, and re-read it. There are all the others tools cpod gives us as well. To higher or lesser degrees, they all require some form of work and mental power. The audio dialogue is no different.
Every new dialogue we hear should be intelligible, at least in part. That’s what learning new language is. Using the tools cpod provides and using them up to a point where we can understand and repeat the dialogue at natural speed, is not always easy, but is real language learning.
Other courses offer slow dialogue. They may be easier, but progress is painfully slow and they are completely impractical for real world use.
Natural speed dialogue may not be the easiest to initially understand and master, but is the most useful and best way of learning.