JBL Synchros E40 BT Specifications, Tests and Review

The wireless headphones JBL Synchros E40 BT allow unrestricted movement, which increases the comfort of using the headphones. This feature is particularly popular with headphones for casual use. However, a certain limiting factor of wireless headphones compared to wired ones is a certain delay in sound transmission between the source and the headphones (but almost indistinguishable for the average user) and the need for regular charging. Unlike wired headphones, wireless headphones are charged separately. The technology used for the sound transmission used by the headphones is Bluetooth 3.0.

The headphones are designed as on-ear. On-ear headphones are generally lighter. However, their design has fewer isolation capabilities, and therefore, for example, more sound can be let in and out compared to around-ear headphones. The weight of the headphones is 205 g.

The sound quality can be affected by many factors. When it comes to frequency range, a wider range will allow more detail to be heard during your listening session. However, it is important to note that the ability to perceive frequencies varies from person to person. The average person is able to hear frequencies in the range of 16 to 20 000 Hz. That is why headphone manufacturers usually focus on the 20 to 20 000 Hz range. If the lower values are lower, headphones are better able to reproduce bass tones, as these represent frequencies up to approximately 256 Hz. Conversely, values from 2 048 Hz upwards are treble. Thus, headphones with a high upper limit will provide a much more accurate reproduction of high tones. Headphones JBL Synchros E40 BT have a frequency range of 20 - 22000 Hz. The JBL Synchros E40 BT reaches the sensitivity values of 114 dB. The sensitivity of the headphones expresses the ability of the headphones to pick up the signal from the source and reproduce it with sufficient volume. The higher the sensitivity, the more easily the signal is converted to sound and the louder the headphones are able to play at a lower power consumption. It is important to remember that high listening volume can consume more energy from connected devices. So if you want to listen to music from your cell phone, it's better to choose headphones with low sensitivity to avoid draining your phone's battery too much. Headphones with a lower sensitivity value (around 85 dB) are better suited for listening in quiet environments, while medium values (around 90 dB) allow for quality listening in noisy environments such as public transport or cafes. Headphones with a high sensitivity value (100 dB or more) are designed for use in really noisy environments such as concerts

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.

The headphones are composed of many various components, one of the most important is the diaphragm. Diaphragm transforms the electrical signal into sound and therefore its quality affects the overall listening experience. There are three types of diaphragms: thin, medium-thick, and thicker. A thin 6 mm thick diaphragm responds quickly to high frequencies but less sensitively to bass. The medium-thick 10 mm diaphragm provides a balanced sound profile, allowing you to enjoy both bass and treble. The thicker 20 mm diaphragm is more sensitive to higher frequencies but has a poorer bass response. These headphones are equipped with the 40 mm.

You will also definitely appreciate the special design of the construction that creates a seal that further blocks out ambient noise and which contributes to undisturbed music listening.

The microphone sensitivity is -42 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.

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 JBL Synchros E40 BT reaches up to 16 hour(s).