How do I get rid of the random pitch changes in VoiceOver on OS X?

Hi. First of all, I am new to Applevis so would like to say hi to everyone. Secondly, I have a question about VoiceOver on the Mac. I am using OS X Mavericks and I notice that VoiceOver sometimes raises or lowers the pitch of the voice when speaking certain content. For example, if you move to the address bar in Safari, VoiceOver says search google or enter an address in a deeper voice. This is extremely annoying and I want to know if there is any way to stop it? Unchecking all the options for change pitch when deleting text and reading capital letters does nothing. Is there a way to turn off these extremely annoying pitch changes? thanks and any help is very much appreciated.