Northampton has few death metal bands, but plenty of stoner doom.Cambridge has two total metal bands on Metallum.Somerville also has two.Malden had one.Medford has four.Arlington has two.Nothing for Stow.
Whoa, five in Amherst, including Lich King.One in South Hadley!Two in Acton.Holy shit, why are there 63 metal bands in Worcester?Lowell has 23. Graveheart is fun. They also have an accomplished video game cover band. (Warning: NSFW/embarrassing-to-be-seen-looking-at album cover.)
Fall River has seven. There may be some correlation to economic depression.
Brockton has ten, and they've been around a while.Everett has two.So, maybe the correlation isn't that tight.
Swinging back the other way to rich towns,
Weston has none, nor do Dover, Sherborn
Brookline has one, and
Newton has two,
Lexington has one,
Belmont has two, and
Watertown has three.Keep in mind that not every metal band is on Metallum, but it's quite compehensive, and small bands are motivated to get themselves on there, so I don't think this is out-of-touch with reality. I might do a more formal analysis later.