The Head-Direct RE1 is a perfect example of a very special earphone that caters only to devoted audiophiles that have need for great sound quality. The special driver design that allows them to scale so well is both a pro and a con. It is a con in the sense that you need to carry around a portable amplifier when you are on the move, but a pro if you factor in the spectacular sound performance these in-ears offer.

The fact that they need a good amp to really shine kind of defies the purpose of using in-ears. For many people in-ears is a convenient option for great sound on the move because you do not need to lug around a pair of full size cans and the in-ears even provide good noise isolation. I am sure you can find a good portable amp that goes well with the sound signature of the RE1s, but that will most likely cost as much as the earphones themselves and add to the bulk of your portable sound rig.

The amazing thing about the Head-Direct RE1s is that they scale so well when amping them. The better the amp, the better the detail, speed, extension and so on. It really proves that the design of the RE1s is something unique and it definitely sets them apart from the other less demanding earphones. The very reason why these earphones sound so good when being fed from a powerful source is also their Achilles Heel, because you need an amp to make them sound good on the move.