Focusrite have released a low-cost, practical solution to referencing your mixes, and it comes in the form of the VRM Box.
The VRM Box as a physical unit serves as a powerful headphone amp, but it also comes with its own software.
The application means that in the final stages of your mix, you can listen to your mixdown in a number of different virtual environments, and on a number of different authentic speakers.
For example, if you had a small studio with small speakers, and wanted to hear what your mix would sound like in a large studio through a pair of KRKs, you could plug in the VRM box, choose this preset, and then hear how this would sound by listening on your headphones.
The development of the software included analysing reverb times, the effects of having different materials in rooms, and the distinctive sounds of certain speakers.