The Define series from Fractal Design is one that used to consist of the single version of the Define Mini along with four versions of the Define R3 that was a huge success for them. From what I can gather, the plan was to keep what makes the R3 such a success, but add things that R3 buyers suggested may need improving or just random suggestions that also made it into this newest chassis that Fractal Design is just releasing as I type this.
I have seen both the Define Mini and the Define R3 where the concept was to deliver good airflow within the chassis while keeping all of the noises in there as well. To do this Fractal Design uses a combination of dense open celled foam behind the bezel while the side panels use a blend of cloth and fibers blended to absorb sounds that other panels allow to pass right through. One feature I really liked was the ability to add fans in the top and sides of these chassis. Beyond that, for those that don't want an extra ventilated build, the ModuVent panels can be used to plug the sound leaks. That along with hard drive trays, black interiors with all black wiring, the accents of white on the trays fans and expansion slots, I mean the list goes on and on for the feature set.
I am really glad to say that all of the features that I liked in the previous Define series chassis are not thrown away or lost in any way in the redesign. With our latest submission of the Define R4 in the Black Pearl attire, you get everything I mentioned with lots of new options and features to, in all honesty, make the Define R3 almost obsolete.
With what I am about to show you, it will be easy to see why I say that. Given the choice from what I have already seen from taking the images and doing the build, there is no reason why if you were looking to them for a chassis you could possibly choose the R3 over the much improved and tricked out Define R4.