Before the advancement of music technology, composers needed to hear their orchestration in their minds. Due to the high cost, testing and modifying orchestrations was never an option during group rehearsals. The composer then had to provide the copyist and orchestra the final orchestration. It was only possible because those composers used to be highly trained in aural skills. In other words, they were capable of hearing the music in their mind before the orchestra plays it.
Since writing music directly into the DAW provides immediate feedback, the aural skill seems not mandatory for composing music anymore. However, the opposite is true.
The new trend focus on the quality, quantity, and combination of tools - the outside. The old trend focus on your internal hearing and mind - the inside.
Less and less, the new orchestrators understand the mechanism of orchestration, where it is common to have instrument playing at a substantial volume but covered by others.
In the second part of episode one, I introduce this concept using percussion and harp as examples.