Hi. I've always used in-ear headphones. I've had ones from Logitech, Superlux, and now Wicked Little Buds. Of them, I've liked my Superlux HD381 the most.
But I've been wanting to try the "big guns" recently, and decided I'd go with the Superlux HD681 Evos. So I went to my favorite audio store yesterday, but they're out of stock. There were test units though, and I was able to try their Evos, 668B, and 661, And even though I thought the Evos stood out, I've noticed that all their outputs aren't that loud compared to my HD381s. I had to crank up the the volume of my phone to the max (Samsung Galaxy Ace with CM10.1).
I was advised that on-ear headphones "need" amplifiers to bring out their potential. Is that true? And if it is, could anyone explain the technical details why iems are louder than on-ears? Thank you.