Everyone hates the sound of his or her own voice whe hearing it on tape for the first time. The reason why is that, when we speak, our ears hear additional internal resonance from the jaw bone. This resonance adds a pleasing depth and warmth to the sound.
Of course, when your voice projects, it loses this resonance, which is why your voice always seems tinny and higher-pitched when you hear it played back.
If you want to compensate for this, there are certain vocal excercises you can try. Chief among these is to speak so that you resonate your voice through the pharyngial cavity at the back of the throat. That will add low end.
To get the feel for this, try yawning a few times. Notice how you feel a vibration at the back of your throat and the sound of your voice begins to deepen significantly.
Now try to speak as if you're yawning. It will sound wierd at first, but eventually you'll get the hang of the muscle movements. With practice, you can consciously direct your voice through the pharyngial cavity to deepen the sound while maintaining clarity.