Comparison Denon AH-GC25W vs Denon AH-GC30

Impedance refers to the headphone's nominal resistance to AC current, such as an audio signal.

Other things being equal, a higher impedance reduces distortion, but requires a more powerful amplifier — otherwise the headphones simply will not be able to produce sufficient volume. Thus, the choice of resistance depends primarily on which signal source you plan to connect the "ears". So, for a portable gadget (smartphone, pocket player), an indicator of 16 ohms or less is considered optimal, 17 – 32 ohms is not bad. Higher values — 33 – 64 ohms and 65 – 96 ohms — will require quite powerful amplifiers, like those used in computers and televisions. And models with a resistance of 96 – 250 ohms and above are designed mainly for Hi-End audio equipment and professional use; for such cases, detailed recommendations for selection can be found in special sources.

The range of sound frequencies that headphones can reproduce.

The wider this range, the more fully the headphones reproduce the spectrum of sound frequencies, the lower the likelihood that too low or too high frequencies will be inaccessible. However, there are some nuances to consider here. First of all, let us remind you that the perceptual range of the human ear is on average from 16 Hz to 22 kHz, and for the complete picture it is enough for headphones to cover this range. However, modern models can significantly exceed these boundaries: in many devices the lower threshold does not exceed 15 Hz, or even 10 Hz, and the upper limit can reach 25 kHz, 30 kHz and even more. Such wide ranges in themselves do not provide practical advantages, but they usually indicate a high class of headphones, and are sometimes given only for advertising purposes.

The second important point is that a wide frequency range in itself is not a guarantee of good sound: sound quality also depends on a number of parameters, primarily the amplitude-frequency response of the headphones.

A system that reduces the influence of ambient noise on the audibility of sound through headphones. "Noise reduction" with the help of a separate microphone (or several micro) "listens" to external sounds and sends the same sounds to the headphones, but in antiphase. Due to this, the noise heard by the ears is attenuated almost to zero and the user can enjoy the sound of the headphones without interference even in a rather “loud” environment. For filtering in headphones, Active Noise Cancellation (ANC) and Environment Noise Cancellation (ENC) systems are used. The first suppresses all the noise around the listener, the second - reduces the noise level of the environment. Active noise cancellation affects the purity of the sound, but the noise from the outside spoils the picture when listening to audio tracks even more.

Also in the headphones there is an adaptive active noise reduction system Adaptive ANC, aimed at automatically adjusting the sound of the headphones depending on the level of ambient noise. In a noisy environment (for example, when traveling on the subway), the Adaptive ANC system enhances the work of “noise reduction”, in the absence of loud sounds from outside, it weakens the noise reduction.

A feature that allows the user to hear the sounds of the surrounding world without removing the headphones.

This possibility is relevant mainly for models with a high degree of sound insulation; so the transparent mode can be found mainly among in-ear models, as well as overhead "ears" of the Over Ear format in a closed acoustic design. A special microphone is responsible for the operation of the function, which “listens” to the surrounding sounds and broadcasts them to the headphones. In Talk Through mode, you can, for example, listen to the interlocutor or control the environment on a busy street. And some headphones with this feature also have more advanced functions, including automatic adjustment to the situation: such models turn on on their own to transmit speech, “hearing” the loud voice of a person nearby. Individual headphones react to loud street noises in the transparent Ambient Aware mode — it means broadcasting noises through the speaker that can be potential danger signals (screams, car signals, etc.).

Note that most models with Talk through also have an active noise reduction function (see above), and the “transparent mode” in them is one of the noise reduction modes. However, exceptions to this rule are possible — technically transparent mode does not have to be combined with noise reduction.

The declared operating time of headphones with autonomous power supply (see above) when listening to music on a single battery charge or a set of batteries.

As a rule, the characteristics indicate a certain average operating time in music listening mode, for standard conditions; in practice, it will depend on the intensity of use, volume level and other operating parameters, and in models with replaceable batteries - also on the quality of specific batteries. However, based on the stated time, you can fairly reliably assess the autonomy of the selected headphones and compare them with other models. As for specific values, relatively “short-lived” devices have a battery life of up to 8 hours, a figure of 8 – 12 hours can be called quite good, 12 – 20 hours – very good, and in the most “long-lasting” headphones the operating time can exceed 20 hours.

The type of connector used to charge the built-in battery of the headphones, or more precisely, to connect an external charger. The role of such a device can be played by a network or car adapter, a power bank, or even a USB port of a PC or laptop (if there is an appropriate cable). At the same time, in true wireless models (there are with a leg, without a leg, with an ear mount and clips (Clip-on)), the "charger" cable is connected to a special docking station, where the "ears" are placed during charging (while the station itself usually has its own battery and can also work as an autonomous power bank). And in wireless and combined solutions of a more traditional design, the charging input is often located on the body of the headphones themselves. As for the connectors, the most common options are the following:

— microUSB. A smaller version of the USB connector, created for portable devices. It appeared quite a long time ago, but it has not lost its popularity in our time, and is used by the absolute majority of manufacturers.

— USB C. A miniature USB connector, positioned, among other things, as a potential successor to microUSB. Unlike its predecessor, it has a two-sided design, thanks to which the plug can be inserted into the socket from either...side. It is still relatively rare, but the situation is likely to change in the coming years.

— Lightning. Apple's proprietary connector. Like USB C, it has a two-sided design, and is somewhat more convenient and reliable, but the use of Lightning is limited to products from Apple itself and its Beats brand.

The total weight of the headphones; for true wireless models (see "Cable Type"), the weight of each individual earbud is listed.

This parameter is directly related to the design (see above) and some features of the functionality. Thus, the mentioned true wireless devices are very light, their weight does not exceed 25 g. More traditional in-ears and in-ears can be noticeably heavier, up to 50g for in-ears and up to 100g for most in-ears. Overhead models, for the most part, are quite massive: among them there are many models weighing 200 – 250 g, 250 – 300 g and even more than 300 g. It should be noted that a significant weight for false ears is often not a disadvantage, but an advantage: it allows them to stay on the head more securely, creates an impression of solidity and reliability, and most often does not create significant inconvenience.