Tracing back exactly the steps an engineer took in order to create that „magic“ mix will be quite difficult and it has a lot to do with accurate monitoring and especially with a ton of experience.
I will try to give you some tips anyway:
The „3D Effekt“ of a stereo mix could be separated into the stereo panorama, produced by the L and R channel.
Here, mid and Side processing comes to mind, which is the principle of mixing the side signal (S = 0.5*(L-R)) and the mid signal (M = 0.5*(L+R)) separate from each other. This enables you to exercise more control over the stereo panorama of your mix, or you might say the horizontal propagation of your mix.
A lot of plugins offer this kind of processing, izotope and brainworks being the most active from the top of my mind.
With MS processing, keep in mind that the side channel is only audible in stereo playback!
The second part of „3D mixing“ could be the „depth“ of the mix. The position of audio material on an axis moving away from you, orthogonal to the L and R axis.
As you already mentioned, reverb does comes into play here. Many plugins offer the option to process early reflections and late reflections separately. Generally, a rule of thumb I use for reverb and distance would say:
- the more early reflections and the less late reflections (or diffuse field) gain, the shorter the distance
- the shorter the pre delay the shorter the distance
- the more dry opposed to wet signal, the shorter the distance
There are some other aspects of distance perception. The air absorption in real life causes small wavelengths to be absorbed while longer wavelengths persist while propagating through space.
Therefore, a damping of high frequencies can amount to longer perceived distance.
There is a great freeware plugin called proximity, which models some of these psychoacoustics related to distance perception. It’s very subtle and I use it for every mix to add depth.
You can never know what additional trickery they used in the daft punk production, but maybe these tips help a little bit anyway ;)
All the best,