Cyber Acoustics AC 645 Specifications, Tests and Review

The Cyber Acoustics AC 645 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 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. Cyber Acoustics AC 645 offers a frequency range of 20 - 20000 Hz. To control the optimum playback volume you can use the manual control directly on the cable.

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.

An important part of these headphones is the diaphragm, which, simply put, converts the electrical signal into a sound. The thin diaphragm that is around 6 mm thick can react quickly to changes in the audio signal and improves high-frequency listening. However, it is less sensitive to bass. The medium-thick diaphragm of around 10 mm provides a fairly balanced sound profile, allowing you to enjoy both bass and treble. A thicker diaphragm of around 20 mm cannot react so quickly to changes in the sound signal, thus impairing bass listening. However, it is more sensitive to higher frequencies. This model features the 30 mm.

Cyber Acoustics AC 645 has a boom–type microphone. The microphone sensitivity is -47 dBV/Pascal. A lower microphone sensitivity will generally ensure that even quieter sounds are caught. On the other hand, in noisier environments, distortion of the recording may occur. With a higher sensitivity, the microphone will not distort the recording even in noisy environments. On the other hand, the microphone will not pick up quieter sounds. So it depends on the environment and the purposes you plan to use the headphones for.