He found her voice soothing and commanding at once.

[alpacinou]

Is this correct? How can I stylistically improve it?

He found her voice soothing and commanding at once. Most men would find it emasculating, but he enjoyed being told what to do by an assertive woman.

 

[Tarheel]

The grammar is fine, but I don't know how her voice can be soothing and commanding at the same time. Perhaps:

He was so comfortable with her that he didn't mind when she told him what to do.

 

[Charlie Bernstein]

Is this correct? How can I stylistically improve it?

He found her voice soothing and commanding at once. Most men would find it emasculating, but he enjoyed being told what to do by an assertive woman.

I don't know that most men would find it emasculating. It could be a turn-on. So I doubt you really need the first part of the second sentence. You could just go right to saying what he likes without comparing him to what other men like.

The seventies had a lot of British songs that did just that — "Lola" by the Kinks, "Maggie May" by Rod Steward, and "Ob-La-Di, Ob-La-Da" by the Beatles come to mind just off-hand.