The JadeAudio EA1 is, according to many people, the exact same IEM as sister-company FiiO's FD1 which has received rave reviews, yet at half the price. Others say it is differently tuned, which may be true or it may be simple unit variance. It is one of the recent crop of beryllium-coated DDs that many prize for their speedy response.
The tuning is probably best described as a mild U-shape, which I found pleasing in almost all genres. The upper mids border on being shouty at times, but this is according to personal preference and is not severe at all.
Bass is quite good, though this is not a bass-head IEM and don't expect it to be. But it's quick and deep, though lacks a bit of physicality. It is mostly linear but with a bit of sub-bass rolloff.
Mids are a bit recessed, but still quite pleasing and moderately detailed.
Treble is good though there is some roll-off and detail levels are budget-tier.
Timbre is dry and at times a bit metallic.
The soundstage is extremely wide, although there is very little central imaging which results in the feeling that the IEMs are not quite inserted all the way even though they are.
They are extremely comfortable, although isolation is only average.
The included cable and tips are quite good for the price, and I don't think there's a need to buy third-party if you don't already have some on hand.
All in all, for $30 these were good bang for the buck when released but have since been eclipsed by other budget offers.