AKG K 840 KL Specifications, Tests and Review

The AKG K 840 KL are wireless headphones that allow unrestricted movement and thus increase comfort while listening to music. Because of this feature wireless headphones are especially popular with casual users. On the other hand, the limiting factor of wireless headphones is a certain delay in sound transmission between the source and the headphones (almost indistinguishable for the average user), and they also need to be charged regularly. Unlike wired headphones, where the headphones are charged by the connected cable itself, wireless ones must be charged separately. The maximum range of the headphones is up to 20 m. This range represents the distance from the sound source at which the headphones with wireless sound transmission can be used. However, the maximum range may be affected by obstacles such as walls or people, etc.

These headphones are designed to fit around the ears. Thanks to the design, they can isolate better from external noise than, for example, over-ear headphones. This allows for better listening quality without interference. However, this design tends to make headphones heavier and less practical for frequent carrying The weight of the headphones is 145 g.

The sound quality can be affected by many factors. For many users the frequency range is a key feature of headphones. The wider the range, the more detail and nuance you will hear while listening. However, every individual perceives frequencies differently, so the frequency range of headphones varies according to individual needs. The average person perceives frequencies in the range of 16 to 20,000 Hz, so headphones with a frequency range of 20 to 20,000 Hz are most commonly available. If you are looking for headphones with a good bass performance, you should aim for lower range values (bass represents frequencies up to about 256 Hz), while high range values (frequencies roughly above 2,048 Hz) will be better for reproducing high tones. The frequency range of headphones AKG K 840 KL is 11 - 31000 Hz. The headphone's sensitivity determines how effectively they can receive a signal from a source. The higher the sensitivity of the headphones, the louder they can play at lower power consumption. However, at high volumes, power consumption increases, which can be a problem when listening to music from a cell phone. A sensitivity value of around 85 dB is suitable for quiet environments, while a value of around 90 dB allows for quality listening even in noisy environments. Headphones with a sensitivity value of 100 dB and above are suitable for extremely noisy environments such as concerts. Headphones AKG K 840 KL are designed with sensitivity about 120 dB/mW.

The device connected to the headphones also plays a role most times. The lower impedance value (approximately 100 to 150 Ohms) is suitable for playback from mobile phones, laptops or other portable players that do not have a powerful enough amplifier. The lower impedance will ensure that the required volume level is achieved with less power, thus extending the life of the player. However, at the same time, with lower impedance, there is more distortion of the sound. Headphones with a higher impedance of around 250 Ohms and above are then more suitable for playback from really powerful signal sources or using a headphone amplifier, otherwise the sound coming out of them might not be loud enough. At the same time, higher-impedance headphones will also ensure less distortion in the sound. In the case of these headphones, the impedance reaches the 32 Ohm value.

In terms of headphone battery life as a significant factor in the purchase decision, it depends on what you want to use the headphones for and potentially how often you will be able to recharge them. Headphones with up to a few hours of battery life are more suitable for home use as they will require more frequent charging. Headphones with a battery life of around 10 hours or more are already more suitable for commuting and shorter journeys. However, nowadays you can also find headphones on the market that have a battery life in the higher tens to hundreds of hours. In this case, you do not have to worry about your headphones simply running out of power on longer journeys, and you will not have to deal with constant recharging. The battery life of the AKG K 840 KL reaches up to 28 hour(s).

The standby battery life quoted by the manufacturer is 336 hours.