Three days after she postponed a concert in Norfolk, Va., Martina McBride is on the phone, her voice showing faint remnants of laryngitis.

“I’ve never had it before,” she says, “but I’m better now.”

First episode or not, the timing was unfortunate. On Jan. 13 McBride opened her 40-stop North American tour, which showcases her versions of more than a dozen classic-country songs from her latest album, “Timeless.” All 18 songs on the album are standards and well-known hits, and they require something extra from performer and audience. McBride heads to Maine to perform at 7:30 p.m. Friday, Feb. 10, at the Augusta Civic Center.

“When I put together this tour I realized it wouldn’t work if I plunked five or six songs from ‘Timeless’ in the middle of the show. It wouldn’t work,” she said. “You can’t get into a groove, the styles are so different.

“So we come out and build around the ‘Timeless’ album. We do 13 or 14 songs from that album, take an intermission, then do an hour of my hits. It’s like two completely different shows.”

That first part, she says, is what requires something new: She has to adjust to a different style of singing, and many of her longtime fans, especially the younger ones, have to adjust to a very different style of country music.

“The first part is real country music,” she said. “It’s definitely not contemporary country. And I’m not knocking that. I have been a contributor to it. But it’s nothing like Hank Williams or Loretta Lynn or Tammy Wynette. If you come to the show expecting to rock out from the very beginning to the end, well, that’s not the kind of show it is.”

McBride was raised on a farm near Sharon, Kan., a speck of a town near Medicine Lodge in south-central Kansas, not far from the Oklahoma border. Growing up, she listened to nothing but Williams and Lynn and Hank Snow, so the music on “Timeless” feels warmly familiar and natural to her – so natural that she at first had a hard time believing there were modern country fans who had never heard it.

“When I was making the album, someone said to me, ‘You realize some of your fans will be hearing these songs for the first time,”‘ she said. “I said, ‘No way. No way. How could they not have heard Hank Williams or “Rose Garden”?’ But it’s true.”

So what was the response to the first three shows?

“The crowds really seemed to enjoy both parts of the show,” she said.

She can’t be too surprised about that, given the album’s retail success. “Timeless” was released in October. The week of its release it topped the country charts and hit No. 3 on the overall sales chart. In December it was certified platinum (1 million copies shipped). Last week, three months after its release date, “Timeless” was No. 11 on the country charts and still awaiting the benefits of her four-month tour.

McBride is one of the most successful and decorated country artists of the last 10 years. She has had more than 20 Top 10 country singles and sold more than 15 million records since 1993. She has been the Country Music Association’s Female Vocalist of the Year four times since 1999. Last year Mattel released the Martina McBride Barbie doll.

That sparkling track record gave her the confidence to decide the time was right to record “Timeless,” an album she has wanted to make for a long time. But it didn’t ensure its success.

“The process of making an album can be so anxiety-ridden,” she said. “You wonder, ‘Will radio play it? Will it be a hit? Will people like it?’ It ends up being stressful. I got to the point where I was tired of thinking about it. I just decided I wanted to make a record that was fun to make where I didn’t have to think about singles or any of that.”

She didn’t have to worry about “singles” because the record is full of them, including the first single off “Timeless,” her remake of “(I Never Promised You a) Rose Garden.” She didn’t have to worry much, either, about how she would adapt, as a vocalist, to the change in styles.

“It all came very naturally,” she said, “which was a little surprising. I grew up with these songs, but I’ve spent the past 14 years singing everything but real, traditional country music. What I realized is how hard I had to work at singing what I’ve been singing. These songs [on ‘Timeless’] are what I was meant to sing. It’s been natural and easy – like falling off a log. But, look, I had a pretty good blueprint to work with: all the original versions. So I wasn’t starting from scratch.”

Her intent in making the album, she said, was not to “make them my own” but to pay tribute to the singers and songwriters by recording versions that stay true to earlier versions. Along the way she realized a few things she hadn’t noticed when she was hearing those old songs back in Sharon, Kan.

“I discovered how amazing the songwriting is,” she said. “The style back then was so simple. I’m a part of the contemporary country style. I did songs like ‘Blessed’ and ‘Wild Angles’ and other complicated songs.

“The old style is such a different style. It’s like watching an old movie or reading a classic book. Styles were so much simpler and elegant back then. It’s refreshing to go back and revisit those periods. It almost feels like starting over.”