One of my ancestral surnames is Behrens. This pronunciation is duly noted in my files. While it's not written as technically as it would be in a dictionary, it serves the purpose. As your research progresses further and further back in time, the chance that living family members have heard the name decreases. Individuals with the name may post replies, but it is important to remember that the pronunciation today may be significantly different from one hundred and fifty or two hundred years ago.
Genealogists use their eyes for the bulk of their genealogical work, and rightly so.
Copyright 1999, Michael John Neill. He conducts seminars and lectures on a wide variety of genealogical and computer topics and contributes to several genealogical publications, including Ancestry and Genealogical Computing. You have reckoned that history ought to judge the past and to instruct the contemporary world as to the future. The present attempt does not yield to that high office. It will merely tell how it really was.