iPhone 5 has no speaker audio

new iphone 5, AT&T model, 64GB, has no speaker audio. at all.

no ringtones make any sound. no alarms make any sound. no notifications make sound. phones calls on speaker make no sound. movies, games, and music make no sound. regular internal handset speaker works ok. headphone jack works ok. bluetooth audio to car works ok.

i've tried resetting all settings. that didn't help. i reset everything, settings & content, and that didn't help either.

any suggestions or ideas?