I have the Blueant s4 it does the same

 

My Nexus One with the BlueAnt S4 has the same problem.

What's interesting is that you can hit the volume-up button on the phone itself while it's giving you the voice prompt and it can be increased to a normal level. It doesn't "stick" though. The next time you use it, the volume goes back down.

 

The issue with blueants s4 it takes too long to make a call,
"blue ant speak to me"
"phone commands"
Then is says something about connecting to your phone
Then you wait to hear the voice no one can hear.
Then you say "Call joe blogs"
Then it dials after finding and saying again very softly the contact name.

Maybe im expecting too much but its too slow.

Its easier to hit the Vlingo widget and just say "call Joe Blogs" and wait for the confirmation?????