If you are looking for professional headphones for critical listening, let’s review the AKG K240 MKII model of a famous Austrian audio producer. They have semi-open cups of over ear wearing style. The headphones are not very versatile for their only connection option with a wire.
AKG K240 MKII specs confirm its above average sound quality for critical listening being very sensitive with 104 dB and having a wide field of frequency response within 15Hz-25KHz. The impedance of 55 Ohm is not the lowest and you may need an amp with a lower impedance receiver to make it sound clean and loud. Still it is quite compatible with players and mobile phones.
The sound of AKG K240 MKII is quite decent for neutral listeners. There is no emphasis on any range and they reproduce music flat. There are no punchy lows and bright trebles. That sounds warm for absence of sharp pitches and boomy bass. The semi open design creates a spacious soundstage that makes me enjoy the music in its airy live reproduction.
The headphones have wired connection with a cable. It is 3 m/9.8 ft long that is quite comfortable and enough for home and studio use.
In spite of its bulky look the AKG K240 MKII is very light and weighs just 240 g/8.4 oz. Large cups sit very comfortable on the ears and allow good airflow for its semi open enclosure. They may not suit some ears for their circular shape. The headband is adjustable and is not tight. It has a thin leather padding but that is enough for a nice fit and I do not feel lack of it. Unfortunately they do not fold for a smaller size for storage and carrying.