When a group of musicians play together, one of the most important components of their sound is the mix of their instruments, and the respective volume of each instrument in the mix. Most experienced musicians have trained their ears to pick up not only melody, harmony and rhythm, but also the subtle differences in volume levels and instrument sounds that make up the overall sound of a group.
To develop a strong sense of instrumentation, dynamics and acoustics, practice listening to individual parts during a group performance, "zeroing in" on particular instruments. Learn the sounds of various different instruments, and how particular sets of instruments sound in combination.
Channel Scramble will train you to quickly catch small changes in the mix of a song. You will also begin to hear more clearly the sounds of individual instruments in various genres and styles.