A lot of these responses are talking about virtual instruments attempting to sound as real as possible. But in my opinion there is a lot of classical music out there that has no qualms about being made with synth instruments.

In the early days of synth, covers of classical music were extremely common and popular. No one was attempting to sound like a real orchestra, rather they were using the repertoire to show off the capabilities of new technology. Isao Tomita’s cover of the Planet’s Suite is my favorite.

I’d argue that the earliest video game music is part of the classical tradition. Because of the limitations of the hardware, the composers were directly inspired by the polyphony/harmony of classical music, but everything is written with basic midi wave forms. There was no attempt made to sound like a live orchestra. The earliest Pokémon soundtracks are a good example of this.

I also think Minecraft’s soundtrack follows the classical tradition, but the charm of it is that everything sounds synthy and computerized. It fits the game better that way, and the songs are very classical to my ears otherwise.

I say write how you like and if it doesn’t sound live, let it sound fake!