We've discussed where speech informaiton is found in the audio spectrum. Significant energy exists in speech up to 5kHz, and most of the information that makes speech understandable lies in the upper end of the speech spectrum. Most moderate hearing loss ( like mine ) is high-frequency loss. That's what makes speech so hard to discerne, even as hearing loss suffers can "hear" speech. The higher the frequencies in the specturm we try to repalce, the shorter the tube can be.
Speech is a very complex phnomenon. Actually, low voices like yours are the biggest problems for we who suffer high freq. hearing loss. You're voice is already lacking in higher clarity frequencies, and so is even harder to understand with moderate hearing loss.