Steve:
The speaker does not really mind the DC component. You would only worry about the DC component if the resultant power being dissapated in the speaker coil exceeds the power rating of the speaker.

There are very many speaker driver applications that are DC coupled to the speaker leads. Take for example a TDA7056A speaker power amplifier with BTL output (balanced bipolar output). One will normally connect this type of output directly to the speaker, altho for a BTL output you must be careful not to ground one side because the speaker is essentially driven via a linear equivalent of an H-Bridge.

Michael Karas