If you are trying to achieve a lower voice for presentations at work, it is a very smart move.  Having a low, crisp voice will demand attention during your presentation.  It will make everything that you say mean that much more to your clients.

Now if you don’t currently have a low voice, don’t worry - you are in luck!  There are a number of things you can do that will improve the sound of your voice, and they are probably not as difficult as you think.  

The most important thing you can do to help lower your voice is simple.  Speak slowly, and keep your chin down.