The sound is from the pop of the ball into the catcher's mitt, he said. The bullpens used to be outside along the foul lines, but this is the first year they've been moved indoors.
"You have enough space, you don't feel like there's anything over you," Hendricks said.
Hendricks noted that at Minute Maid Park in Houston, the lighting is a little strange where the bullpens are located.
"Here, they did a good job, it's so enclosed, the lighting is perfect, and you can see your lanes well," Hendricks said.
Jon Lester asked bullpen coach Lester Strode to open the bullpen door so he could hear what was going on outside Monday night because it was a little too quiet while he was warming up.
"It is really quiet in there, and it can get kind of warm," Hendricks said. "But the mound is perfect and it felt just like the game mound."
Cubs keep busy • It's been a whirlwind week for Javier Baez, who took part in the banner-raising ceremony on Monday night, had a street in Chicago named after him on Tuesday, and received his championship ring on Wednesday.
"It's like a dream, man, it's like a dream," Baez said. "It's been pretty early to have all this happening in my career. It's really exciting, and I'm just living in the moment."
A street in Humboldt Park, which has a large Puerto Rican community, was named after Baez, 24, and Chicago Mayor Rahm Emanuel took part in the ceremony.
"To see all the people there waiting for me, it was really exciting," said Baez, who helped Team Puerto Rico earn silver medals in the World Baseball Classic.
A few other Cubs players also were busy on Tuesday, an off-day on the schedule. Anthony Rizzo, Willson Contreras and Mike Montgomery surprised fans on American Airlines flights, Kris Bryant hit home runs into the Chicago River as part of a promotional event, and Kyle Schwarber posed as a mannequin in a store window, then answered fans' questions.
"It's all fun stuff, and that's what happens when you win," manager Joe Maddon said. "I believe our guys can balance things."
Maddon didn't think he needed to say anything to the players about keeping their focus on the field.
"I have a lot of faith in our guys and how they are," Maddon said. "I won't even talk to them about that, because then I'm kind of insulting them if I do."