In 1958 at the age of 15, McNab began playing with the Young Musicians Foundation Debut Orchestra under conductors Dr. Miklos Rosza, Lawrence Foster, Gerhard Samuel and Henry Lewis.

After touring with the San Francisco Ballet and service in the U.S. Army, playing with the West Point band, he studied privately in New York City with John Ware and William Vacchiano.

He has performed on albums by jazz musicians such as Les McCann, and from 1975 until its demise in 1988, McNab played trumpet with the experimental session group, the Abnuceals Emuukha Electric Symphony Orchestra.

the Extra-Terrestrial, Jaws, Scrooged, Cocoon: The Return, Coming to America, Indiana Jones, Star Trek, The Package, The Karate Kid Part III, The Little Mermaid, Field of Dreams, Glory, The War of the Roses, Always, Hard to Kill, Nightbreed, Pretty Woman, Hoffa, The Edge, Soldier, Dick Tracy, Home Alone, Edward Scissorhands, The Bonfire of the Vanities, Misery, Hook, Beauty and the Beast, Final Analysis, The Rocketeer, Sleepwalkers, Robin Hood: Prince of Thieves, The Chronicles of Narnia: The Lion, the Witch and the Wardrobe, Jurassic Park, Wyatt Earp, Outbreak, First Knight, Small Soldiers, Far and Away, Dinosaur, The Nightmare Before Christmas, Batman Returns, Batman Forever, Peter Pan, Atlantis: The Lost Empire, National Treasure, Treasure Planet, The Simpsons Movie, Spaceballs, Aliens vs.

Predator: Requiem, Timeline, Spider-Man, Under Siege 2: Dark Territory, Meet the Robinsons, The Patriot, Waterworld, Serenity, The Net, My Fellow Americans, Space Jam, Toy Story, James and the Giant Peach, A Bug's Life, Monsters, Inc., The First Wives Club, Mars Attacks!, 101 Dalmatians, Dante's Peak, Liar Liar, Cats & Dogs, Mulan, The Matrix, Planet of the Apes, War of the Worlds, Godzilla, Starship Troopers, The Polar Express, The Wild, The Lost World, The Shadow, Men in Black, Leatherheads, Minority Report, The Pursuit of Happyness, Speed 2: Cruise Control, Batman & Robin, My Best Friend's Wedding, Hercules, Mission: Impossible, Van Helsing, Firewall, Signs, Dreamcatcher, Meet Dave, Monster House, The Sixth Sense, The Sum of All Fears, Transformers, Pirates of the Caribbean, Hulk, G.I.