Pronunciation: V sound in "of"

[WilliamTaft]

An example sentence using "have to" in Longman Advanced American: The price of houses has to go up sooner or later.

I heard a D sound rather than a V sound. What do you hear?

 

[probus]

In all four cases I hear the V clearly and no D.

 

[teechar]

It does sound a bit like a computer-generated pronunciation, at least in the "of houses" part.