Comparison ACME BH-316 vs ACME BH-317

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.

Rated headphone sensitivity. Technically, this is the volume at which they sound when a certain standard signal from the amplifier is connected to them. Thus, sensitivity is one of the parameters that determine the overall volume of the headphones: the higher it is, the louder the sound will be with the same input signal level and other things being equal. However, we must not forget that the volume level also depends on the resistance (impedance, see above); moreover, it is worth choosing “ears” for a specific device first by impedance, and only then by sensitivity. In this case, one parameter can be compensated for by another: for example, a model with high resistance and high sensitivity can work even on a relatively weak amplifier.

As for specific figures, headphones with indicators of 100 dB or less are designed mainly for use in a quiet environment (in some similar models, the sensitivity does not exceed 90 dB). For use on the street, in transport and other similar conditions, it is desirable to have more sensitive headphones — about 101 – 105 dB, or even 110 dB. And in some models, this figure can reach 116 – 120 dB. and even more.

It is also worth noting that this parameter is relevant only for a wired connection according to the analogue standard — for example, via a 3.5 mm mini-...jack. When using digital interfaces like USB and wireless channels like Bluetooth, the sound is processed in the built-in headphone converter, and if you plan to mainly use this kind of application, you can not pay much attention to sensitivity.

Bass boost function for powerful and rich bass. Often implemented as a single button, with which you can actually "turn the bass on and off." Bass Boost is more convenient than adjusting low frequencies with an equalizer; in addition, various special technologies can be used to enhance the bass.

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 technology used in Bluetooth models (see "Connection") that allows the headphones to connect to multiple devices at the same time. Thanks to this, you can, for example, listen to music from a laptop, and when a call comes in on a mobile phone, switch the headphones to a conversation. This technology has its own characteristics for different manufacturers, and therefore, if the multipoint function is critical for you, you should separately clarify the details of its operation in the selected model.

The time required to fully charge the battery in properly powered headphones (see above).

In this case, we mean the battery charging time from 0 to 100% when using a standard charger (or a third-party charger with identical characteristics). Accordingly, in fact, this indicator may differ from the claimed one, depending on the specifics of the situation. However, in general, it is quite possible to evaluate different models and compare them with each other: headphones with a shorter claimed charging time will in fact charge faster (ceteris paribus).

Also note that an increase in battery capacity (and headphone battery life) inevitably implies an increase in charging time. To compensate for this moment, special fast charging technologies can be used — however, they affect the cost and require the use of specialized charger.

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.

For full-size headphones, ear pads are often made of genuine leather, leatherette, textile, velor, leatherette, memory foam, as well as their combined variations. In the caste of in-ear headphones, completely different materials are used - the most common are silicone pads, which gently adapt to the individual structure of the auricle, and as an alternative to them, foam ear pads with a porous structure (so-called “sponges”) are offered. Here are some features of commonly used ear pad materials:

- Textiles. Fabric ear pads are usually found in budget headphone models, but sometimes they are also used in the premium segment. The tactile textile ear pads are pleasant to the touch, and they also allow air to pass through well. In terms of acoustic properties, these are completely neutral materials. Note that such ear pads can be made from various types of fabrics (for example, microfiber).

- Leatherette. Artificial leather substitutes are used in headphones of all price categories. In fact, the properties of this material depend on the specific type of leatherette: ear pads made of conventional eco-leather can have excellent “breathing” qualities, while low-grade leatherette often provokes increased sweating of the ears (especially in the hot season).

- Genuine Leather. Genuine leather is a premium product used in corresponding flagship-level...headphone models. Thick leather provides proper sound insulation and deep bass response. At the same time, your ears may sweat when using leather ear pads. To avoid increased sweating, the leather is often made perforated.

— Velor. The most delicate material to the touch with excellent sound-absorbing abilities. Velor ear pads provide good noise insulation, and headphones with them do not cause fatigue even after a long stay on the head. However, the material also has disadvantages: it gets dirty easily, attracts dust and pet hair, and wears out quickly.

- Alcantara. Ear pads made of artificial suede, which are as close as possible in properties and tactile sensations to velor products. However, Alcantara is easier to clean from dirt and lasts much longer. Alcantara ear pads are found in top-level headphones.

- Foam rubber. Foam ear pads are the prerogative of budget over-ear headphones. The fact is that this is a short-lived material that often requires replacement due to its low strength. Partially, special impregnations solve the problem, but foam rubber still retains its structure for a relatively short time.

- Fur. Quite a rare type of material for making ear pads. Headphones with characteristic fur ear pads perform a practical function - they warm the listener’s ears during the cold season.