Here’s a game that only somebody like Bob Ludwig can play: Sometimes, when he’s out to dinner with his wife and there’s a radio playing, they count the number of consecutive songs he helped create.

“I think we’ve gotten up to five in a row at one point, and that’s pretty fun,” said Ludwig, 72, who has been one of pop music’s most in-demand mastering engineers for the past 45 years.

Working at Gateway Mastering Studio in Portland, attached to a parking garage on Cumberland Avenue, Ludwig and fellow mastering engineer Adam Ayan have the final creative say on recordings by dozens of Grammy-nominated artists each year. The two have 12 Grammy Awards between them and have worked with a who’s who of music stars, including the Rolling Stones, Bruce Springsteen, Elton John, Carrie Underwood, Beyoncé and Barbra Streisand.

The pair will talk about what they do and what it’s like to work on so many hit songs on Tuesday as part of the Portland Press Herald’s MaineVoices Live series. The event starts at 7 p.m. at One Longfellow Square in Portland.

Their work is sort of low-profile, since most people don’t know what a mastering engineer does and they work mostly alone in their Portland facility, on recordings sent to them. But it’s high profile because of their client list and the attention they get in the music business, including Grammys. From 2013 to 2015 Ludwig won three consecutive Album of the Year Grammys, considered perhaps the most prestigious, for recordings by Mumford & Sons, Daft Punk and Beck.

Ayan won a Grammy in 2005 in the best historical album category for “The Complete Library of Congress Recordings by Alan Lomax,” and he has also won five Latin Grammys. From country to classical, from hard rock to Americana, it’s hard to go a day listening to the radio or Spotify and not hear something Ayan or Ludwig worked on.

“I still get giddy when I hear a song I worked on come on the radio,” said Ayan, 41, who has worked with Ludwig at Gateway for 18 years. “I feel so lucky to be doing this.”

So what is mastering? Both Ludwig and Ayan describe mastering as the final creative step in making a single or album. A recording starts with musicians working with a tracking engineer or recording engineer, the person who sets up the microphones and records the singers and musicians, often in separate locations. Then the tracks, usually on digital formats these days, are handed to the mixing engineer, who takes all the individual tracks – guitar, bass, drums, keyboards, various vocals – and mixes them together into one cohesive work.

The fully mixed album is given to the mastering engineer, who listens for distortion, hissing, imbalances and other elements that stop the recording from sounding as good as it can. Ayan and Ludwig say they usually spend a full day mastering one album, using control panels with hundreds of levers and knobs, plus computer software, to make the sound adjustments.

Listening is a very important part of the job. Before he was hired by Ludwig, Ayan took a listening test. He listened to recordings that had mistakes Ludwig put in on purpose, but also had some crazy-sounding notes the artist meant to put into the song. He passed.

Ludwig worked as a mastering engineer in New York City for more than 20 years before deciding to open Gateway in Portland in 1993, partly because his parents had moved from New York to Maine. When he made the move to Portland, Ludwig felt few artists would travel here to sit in on his mastering sessions, because of the location and because there really wasn’t that much for them to do. But Ludwig found that more artists visited him here in Portland than in New York City. For a while in the ’90s, it was a sport around Portland to spot the rock stars in town to work with Ludwig. Eric Clapton was spotted having a hamburger at Ruby’s Choice on Commercial Street and Bruce Springsteen could be seen lugging his gym bag to the Bay Club in One City Center for his daily workouts. Now, because of computers, the Internet and other massive changes in the recording industry, record companies don’t have big budgets and artists don’t travel to mastering studios as much. Ayan works with a lot of Nashville-based country artists, who rarely come for one of his sessions. Ludwig sees fewer musicians dropping by for his sessions, but there still are some who come regularly, including Springsteen. J. Geils frontman Peter Wolf comes by to master his solo works. Regina Spektor stopped by when she was in town for her show at the State Theatre in early March.

Jeff Tweedy of Wilco, Jim James of My Morning Jacket, and Conor Oberst of Bright Eyes have also come for mastering sessions.

“Those three are such talented guys. You can give them a guitar on the spot and they can create something amazing,” said Ludwig. “When they come, they are very focused, but they let us do our thing.”

Ray Routhier can be contacted at 210-1183 or at:

rrouthier@pressherald.com

Twitter: @RayRouthier