AKG K99 Headphones - Reviews
Pros: Very light and insubstantial. Neutral, textured exiciting sound. Loud without amp. Good detail, soundstage and imaging for the price. Minimal design
Cons: tonality is a bit off, leakage, needs amp/good dac to get good sound, ear cups hard and uncomfortable
*note the one I have are the new perceptions not the old ones, not sure if there's a difference other than a logo change*
These cans are pretty under the radar, but if you can get them for a cheap price (I paid 50 bucks CAD for these)  and you have an amp or a good dac, then they may surprise you.
They are semi open, but leaks like a open can without the soundstage those types of headphones have. Still pretty good for the price however. And don't let the loudness fool you, without an amp, they sound thin, muffled and lacks bass, not pleasing at all. If you don't have an amp then don't bother with these. Otherwise, they're pretty good, kinda exciting actually.
This level of AKG gets no love here at Head-Fi. I don't know why as they are built better than most at this price point? They have great sound detail, scale with source and amping and are genuinely fine headphones. Let's not even get into the perfect soundstage.