The K 240 DF follows the criteria specified by the Institute of Radio Technology (IRT) in Munich for a "diffuse field" equalization curve that provides headphone listeners with the sound pattern, characteristic of a room with reflective, non-anechoic surfaces. Each K 240 DF is rigorously tested to assure strict adherence to the IRT standards for frequency response, channel separation and sensitivity.
The K501 is AKG's top of the range model except of the K1000. It gives a wide spectrum and well balanced sound and is extremely comfortable to wear. The K270 is a closed type of headphone, is a little heavier then the K501 and gives best results where better sound insulation then with an open type of headphones is required. It allows excellent bass reproduction and by the fact that two drivers are used per channel gives very high distortion-free sound pressure levels and a good transient response.
The K240DF is acoustically equalised to the diffuse sound field. They refer to such a sound field present in a reverberation chamber using third-octave filtered pink noise and measured in the close vicinity of the ear drum with a measuring probe. Especially at times, when program material is exchanged between stations internationally and the monitoring facilities vary greatly still, it looks extremely sensible to exclude the varying acoustical parameters of the different monitoring rooms and refer to standardised headphone monitoring when comparing program material. To my experience and of course taste the K240DF give an utmost analytic and uncolored sound and allows critical listening to especially orchestral and chamber music.
K501 Headphones
Uses VarimotionTM large diaphragm design for good spatial separation and outstanding
sound resolution. Response extends from 16 Hz to 30 kHz. Ideal for lovers of classical
music. Uses circumaural earcup with open acoustical design.
Recommended for:
Classical listening
Home studio applications
FM broadcast monitoring
Multimedia applications
K401 Headphones
These headphones provide all that rock and pop music enthusiasts want to
hear: tight, powerful bass, crystal clear sound quality and impressive power.
Uses VarimotionTM diaphragm design for outstanding sonic and spatial
resolution.
Recommended for:
Pop/rock listening
Home studio applications
Multimedia applications
Broadcast monitor applications
K301 Headphones
These phones have recently been redesigned, using a large diaphragm with
high internal damping for smoother overall response. The open design
makes for excellent, fatigue-free listening.
Recommended for:
Home listening of all kinds
Multimedia applications
Home studio applications
K270S Studio Headphones
These phones have a closed design and are ideal where leakage from the
phones into nearby microphones must be avoided. Motion picture
recording using "click tracks" for synchronization is an example of this.
When the phones are removed, a switch is opened that mutes the phones.
This switch is a big advantage in eliminating feedback and leakage from an
unattended pair of headphones. Two transducers are used in each earcup
for added output capability. Low impedance (75 ohm) design
Recommended for:
Studio and vocal/drum booth usage
Use in high ambient noise environments
ENG operations
Sound reinforcement monitoring
K240DF Monitor Headphones
The K240DF meets specific criteria of the IRT (German Radio Institute)
for diffuse-field equalization, which is ideal for broadcast monitoring,
setting a standard by which program material traveling internationally
can have a common listening reference. The design is circumaural,
semi-open for listening comfort, and the high impedance (600 ohms)
facilitates studio monitoring, with multiple phones connected in
parallel. These phones sound slightly flatter than the model K240M.
Recommended for:
Broadcast transmission monitoring
High accuracy home listening
Recording studio monitoring
K240M Monitor Headphones
The K240M is one of AKG's top selling models and is a virtual standard
in recording and broadcast studios. The design is circumaural, semiopen,
and the response extends down to 15 Hz. Excellent wearing
comfort.
Recommended for:
General recording and broadcast studio use
Home listening
ENG operations
All headphone monitoring activities