The Scottish National Jazz Orchestra has attracted many compliments in the past few years.

After working with the orchestra as its featured soloist in 2012, American trumpeter Randy Brecker volunteered that SNJO "is among the very best jazz orchestras on the planet" and that his dates with the orchestra gave him one of the most enlightening experiences of an already very eventful life.

A more recent guest, saxophonist Dave Liebman praised the orchestra's professionalism and flexibility and added he couldn't say enough about the band's director, Tommy Smith, who Liebman ranks "up there with the best as a leader-conductor as well as a player" - and Liebman has worked with major jazz personalities including Elvin Jones, Miles Davis and Chick Corea.

These hymns of praise won't get any argument from SNJO's featured soloist this weekend, vocalist Kurt Elling, who is making his second appearance in Scotland with the orchestra, although they have now worked together quite a few times, including concerts at two of Europe's leading jazz events, London Jazz Festival and Normandy's Jazz sous les Pommiers, as well as Elling contributing to SNJO's latest album, American Adventure.

"I've been very impressed by the musicians' work ethic and the complexity of what they're willing to take on," says Elling, who works regularly with big bands around the world - he's off to Norway after this weekend's concerts to sing with a jazz orchestra in Oslo.

"I like the power and versatility of a big band and how an orchestra can vary the dynamics from very loud to very quiet, and SNJO covers those bases. Plus they swing really hard, which I like."

For Elling's return, he and SNJO director Tommy Smith have compiled a repertoire of songs that explore life's philosophies, though Elling notes that it was Smith - and not he, the former divinity student who spent a year studying in Edinburgh in the 1980s - who came up with the umbrella term Syntopicon for the concerts' title.

"We both wanted to have new arrangements of songs we haven't played before," says Elling, "and as an artist you tend to have lists - things you're currently working on, things you've worked on and might need revision, and things you desire to do and people you desire to work with.

"Tommy knows the direction I like to take, I trust him, and he was able to match material that I would be able to write words for or just enjoy exploring with some of the best arrangers in the world."

A syntopicon, says Elling, is a group of topics that, in this case, use music to communicate love, life, joy, beauty, knowledge, language, and courage. Among the new arrangements that Smith has commissioned are pianist Geoffrey Keezer's take on Somewhere, from West Side Story, former Weather Report bass legend Jaco Pastorius' Three Views of a Secret in a setting by Fred Sturm with words by Elling, and German pianist and long-time SNJO colleague Florian Ross's exploration of the traditional Loch Tay Boat Song.

"I didn't arrive on the scene until after Jaco Pastorius had passed," says Elling, "but Three Views of a Secret is a long-time favourite of mine.

"It's beautifully written and full of joy and energy and it has a special quality in that it's unusual and yet you feel you've heard it before.

"It also has a great title and that gave me some place to take it with lyrics."

For Elling, who later this year will be renewing the partnership with guitarist Charlie Hunter that proved such a success at the Edinburgh Jazz Festival in 2012, the ultimate attraction in the music that comprises Syntopicon is the challenge it offers him as a singer and as a person.

"You want to be doing your best work whatever field of the arts you're in because your life's going to be over all too soon and you have to make the most of it," he says.

"I'm here to take on as big a challenge as I can and moving on, be it to another big band, my own small group or that group I have with Charlie helps me do that. It keeps my head spinning, too, but that's a good thing."

Kurt Elling and the Scottish National Jazz Orchestra present Syntopicon at Perth Concert Hall on Friday, February 21; Queen's Hall, Edinburgh on Saturday, February 22; and Royal Conservatoire of Scotland, Glasgow on Sunday, February 23.