Review on AKG K240 Studio Semi-Open Over-Ear Professional Studio Headphones with Knox Gear Headphone Amplifier: Enhanced Audio Experience for Studio Professionals by Eric Beck

These are my first outdoor headphones and I was initially disappointed with the sound quality, especially at low frequencies. Connected to a closed-loop amp, these headphones simply don't produce any power at low frequencies. This makes the sound flat and the mids too distinctive and dull. It's not a good sound at all. It wasn't until I connected the headphones to my LG V20, which has a DAC and delivers more power, that these headphones worked flawlessly. And wow what a DAC counts. Even with a weak DAC/amp on my phone I can tell you what an impressive sound these headphones can produce. Listening to music in High Definition 96/24 and higher has changed my idea of good sound. I 100% recommend these headphones at a great price, just don't expect bass from closed headphones and get a DAC/amp. to go with them, even for $20 this amp doesn't fit. (I'm not sure, but the amp doesn't have independent channel switching; if I plug my cheap noise-cancelling monitor into channel 2, some of that noise will be introduced into channel 1, which the headphones are plugged into, and worse, cause clipping on the right side of the headphone. A corner has probably been cut off in this diagram.)