Plug
The design of the plug provided in the headphones. This parameter is relevant primarily for models with a mini-Jack interface (see "Connection") — the rest of the plugs are made straight in most cases, exceptions are extremely rare.
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Direct. The traditional, most simple and unpretentious option is plugs that do not have any bends. Usually, they are compatible without restrictions with stationary audio equipment, PCs, laptops, etc. But for smartphones and other portable gadgets, this option is not always optimal — it all depends on how the gadget is located in your pocket or case. In some cases — for example, when carrying a smartphone in a regular pants pocket — such a wire can be strongly bent around the plug, which quickly becomes unusable; in such cases it is worth paying attention to L-shaped or curved plugs (see below).
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L-shaped. Plugs angled at 90° in the shape of the letter L. Designed primarily for use with smartphones and other handheld devices: such devices, when worn, can be positioned in such a way that a bent plug is more convenient than a straight one. However, the L-shaped design may also be the best choice for stationary equipment, where the headphone wire approaches the connector at a right angle — for example, this situation is often found in computers and laptops.
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At an angle of 45°. A variation of the L-shaped plug
...described above, bent not at a straight line, but at a smaller angle (not necessarily exactly 45 °). It is also designed primarily for pocket equipment, and with such an application, such plugs are considered even more convenient and reliable than traditional L-shaped ones. But for stationary devices, it hardly makes sense to specifically look for a model with a similar connector (although such an application is technically quite possible).Frequency range
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.
Sensitivity
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.Speaker size
The diameter of the speaker installed in the headphones; models with multiple drivers (see "Number of drivers"), usually, the size of the largest speaker is taken into account, other dimensions can be specified in the notes.
In general, this parameter is relevant primarily for over-ear headphones (see "Design"). In them, emitters can have different sizes; the larger it is, the more saturated the sound is and the better the speaker reproduces the bass, however, large emitters have a corresponding effect on the dimensions, weight and price of the headphones. But in-ear "ears" and earbuds, by definition, have very small speakers, and rich bass in them is achieved due to other design features.