You did your best with reverb, eq and compression, yet your mix sounds “uncomfortable”?
If you know that notion, you should make yourself familiar with saturation. Saturation is an effect that is provided by tube and tape recorder plug-ins. They come from the analog world and what they do is kind of magic that only a handful of people really understand. There’s a lot of different things going on including eq, compression and exotic stuff like phase shifting and distortion. Distortion? Yes, the kind that makes the sound “rougher”, but also “more human” and pleasing to the ear. Too much of it and the mix is destroyed, but in small doses such saturation plug-ins can work magic!
My approach: Since I discovered the UAD Ampex Tape Recorder plug-in, it’s a no-brainer in all of my orchestral mixes. I put it at the end of the mastering chain, after eq and compression. If you are – like me – no engineer, but a composer, don’t try to understand what it does, just experiment with the factory settings, listen to the results on everyday speakers and headphones, and save the setting that is best suited for your mix.
btw: If you have special recommendations or experience with saturation plug-ins that you want to share, please do so here or on Twitter!