TODAY | June 15, 2013
>> reporter: when jim cornelsen goes to work in chicago he has 22,000 people waiting for him. o say can you see
>> reporter: he belts out the star spangled banner before blackhawks games in a building fans call the mad house on madison.
>> this is as close to being a rock star as an opera singer is ever going to get.
>> reporter: for years in chicago the anthem has become a deafening show of pride and spirit. but now with the blackhawks playing the boston bruins in the stanley cup finals there's a little friendly competition.
>> reporter: because this fellow warming up his vocal cords is the bruins anthem singer rene rancor.
>> it's getting there.
>> reporter: he's been doing it for nearly 40 years.
>> i imagine that i'm in an opera house and it's a great thrill each time.
>> reporter: he is so popular many purchase t-shirts to look just like him. he was also present in the aftermath of the boston bombings where he simply led the fans as they stood and sang. were so gallantly streaming
>> when the fans started in so strongly with such feeling i was just moved to tears. it was just an incredible moment.
>> reporter: both men say they're honoring u.s. servicemen and women when they sing. cornelson shares his little corner of the ice with two of them. and it's when he gestures toward the flag that the crowd takes its cue and roars.
>> the focus is what the anthem is about. we're cheering as americans. we're cheering in support of feeling good about being patriotic. and the home of the free
>> reporter: for today kevin tibbles nbc