Normally Soames rhymes with the words "combs" and "domes".
It is an English surname originally, indicating that one's ancestor came from a place called Soham in Cambridgeshire or Suffolk. The place name meant "homestead by a swampy pool."
The above information is from
A Dictionary of English Surnames by Reaney &
Wilson; and
A Dictionary of English Place-Names by A. D. Mills.