I have had three soundbars over the last four years. Only one so far really did a very good job of reproducing voices.
Yamaha YSP-900 - good sound - poor dynamics and ultimate volume - mediocre on voices
Sony CT-100 - almost the same as the Yamaha but even less dynamic range
Vizio (don't know the model number) - excellent dynamics and by far the best with voices of any of the three.
Since there was a difference of more than ten to one in the price from high (Yamaha) to low (Vizio), I recommend you start low, but purchase somewhere with a good return policy. The Vizio can be had for less than a c-Note at Wal-Mart with easy return policy. If you find it lacking, return it and try something different.
The JVC soundbar has had a number of reviews stating that it handled voices well also. About double the price of the Vizio. I have not heard this either in a home or retail environment.