The Trading Fours jazz group plays their regular Friday concert tonight at Silverheels Bar & Grill at 6th and Main in Frisco, but with a few new additions.First, after recently losing drummer Alton Scales to the Community College of Aurora, they have acquired new talent in Joshua Cohn, a local contractor and 20-year jazz percussionist.Also, jazz vocalist Heidi Schmidt rejoins the group tonight to perform jazz favorites and a few of her original songs. Schmidt performed with Trading Fours for a number of years before leaving Summit County to study jazz vocal performance at the University of Denver's Lamont School of Music. She recently performed at the Festival Jazz en Vercours in Villard de Dans, France. Accompanying Schmidt on trombone is Dick Foust, a 30-year Nashville recording veteran, now of Silverthorne. You may have heard his horn backing up the performers at the recent run of "Kiss of the Spider Woman" at the Lake Dillon Theatre. Cohn, Schmidt, Foust and the rest of the Trading Fours will perform on the deck at Silverheels Bar & Grill from 6-9 p.m. today.