This refers to the spectrum of ‘standard’ English spoken by newscasters, TV actors, and a large percentage of middle-class Americans.
The short-a (as in cat) is raised and diphthongized before nasal consonants. Hence man and can’t are pronounced something like IPA meən and keənt (“meh-uhn” and “keh-uhnt.”)
Rhotic, meaning the r is pronounced at the end of words like car and mother.
Words like lot and rod are pronounced with an unrounded vowel, as lɑt and ɹɑd (“laht” and “rahd”).
The diphthong in words like boat and rode is pronounced relatively back: i.e. IPA boʊt and roʊd
Actor Topher Grace (wait till after the ad at the beginning).
News Anchor Brian Williams.
Doctor and writer Atul Gawande.
Eastern New England English
This describes the classic “Boston Accent.” It also refers to related accents in Eastern Massachusetts, Rhode Island, Maine, Eastern New Hampshire and Eastern Connecticut. The most important feature of this is non-rhoticity: unlike other American accents, New Englanders drop the “r” at the end of syllables. Hence the famous phrase “pahk yuh cahr in hahvuhd yahd” (Park your car in Harvard Yard).
Non-rhoticity, as mentioned above.
Fronted pronunciation of words like father and palm, so these are pronounced IPA faðə and pa:m (i.e. this vowel is close to the vowel in words like “cat” and “mad” in General American).
Unlike most other American accents, the vowel in lot and rod is rounded as in most British dialects, pronounced IPA lɒt and ɹɒd (“lawt” and “rawd”). Note that this feature is less prevalent in some sub-dialects, such as Rhode Island.