help with verbalizing strike call

[shipwreck]

At my last evaluation for college ball, I was told that my verbal strike call was a little weak. I simply say strike and come up to a hammer. On the day I was evaluated, it was real windy and they told me I wasn't loud enough. What has anyone found to be a good sound to make for a strike, that has sound that can really be heard without yelling it? Along with that, how do you end with a strike three to put more emphasis on it? Just trying to improve. Dave