Piotr writes:
 
On the other hand, in some people's speech the whole coronal sequence in _Andrew_ or _entry_ is clearly postalveolar.
This is a useful example.
 
I can say 'Andrew' with my tongue nicely related to the alveolar ridge, just behind the upper teeth. I can also do it with the tongue pulled back forming the 'd' against the area past the aveolar ridge the start to curve upward towards the dome of the mouth. I do it both ways, but the latter way is perhaps more common.
 
Mark.