Koss P/15 Specifications, Tests and Review

The Koss P/15 are wired headphones. In the case of studio and professional DJ headphones, a wired connection is a standard and a necessity. In this case, connecting via cable reduces audio transmission delays and prevents unwanted battery drain as it would be in case of wireless headphones. The same is de facto true for gaming headsets. In case of headphones for normal music listening, the cable is rather a relic, although it still has its fans. However, the wireless option is much more popular for everyday use in today’s world.

The headphones are designed as in-ear. In-ear headphones are plugged directly into the ear and they normally offer complete or at least partial isolation from surrounding noise. The degree of isolation also depends on whether the headphones have an ambient noise isolation function. Their indisputable advantage is that they are more compact than over-the-head headphones.

The sound quality can be affected by many factors. When it comes to frequency range, the wider it is, the more detail you will hear when listening. However, the range a person can perceive is highly individual. The average person is able to perceive frequencies in the range of 16 to 20 000 Hz. So the most common frequency range you will see on the market is 20 to 20,000 Hz. Lower frequencies up to approximately 256 Hz are considered bass frequencies. Therefore, the lower the bottom value is, the better the headphones will reproduce bass. Conversely, values from approximately 2 048 Hz upwards are treble. That is why headphones with a high upper value will provide a much more accurate reproduction of high notes. Koss P/15 offers a frequency range of 40 - 20000 Hz. The sensitivity parameter determines how sensitively the headphones can receive the signal from the source. The higher the sensitivity value, the louder the headphones will be able to play with less power consumption. In general, a higher listening volume also means a higher power load for the connected device. So if you're buying headphones to listen to music from your mobile phone, for example, this is relevant to think about as you don't want to drain your phone's battery too much. Lower values around 85 dB are more suitable for listening in more quiet environments (for example, at home or in the office). Medium values of around 90 dB can provide good listening quality in noisier environments (for example, on public transport or in cafés). Headphones with high sensitivity values of around 100 dB or more are designed for really noisy environments, such as concerts. The Koss P/15 has 102 dB.

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. Total Harmonic Distortion of these headphones is Audio Output | Total Harmonic Distortion. The value quoted by the manufacturer is usually the average distortion over all reproducible frequency bands. This is not a crucial parameter to decide on when making a decision, but on the other hand, keep in mind that higher harmonic distortion can negatively affect sound quality.