As you know, knowledge is power, especially in technical matters. The main characteristics of the headphones, usually indicated on the packaging, give an idea of \u200b\u200btheir capabilities before listening. You just need to figure out what's what.
Sensitivity
Everyone has come across a situation where some headphones sound louder than others, despite the fact that the level on the player (or smartphone) is set the same. This fact is often associated with the difference in the power of the headphones. But headphones are not an amplifier, this premise is fundamentally wrong.
In fact, how loud the headphones sound depends on their sensitivity. Traditionally, this parameter lies in the range of 90–120 dB, and for most models available on the market these limits are already 95–105 dB. Sensitivity indicates how loud the headphones will play, all other things being equal. The higher it is, the higher the maximum volume and less load on the built-in amplifier of a player or smartphone. I noticed another direct relationship: the cheaper the headphones, the less chances that their real (and not specified in the technical data sheet) sensitivity will be high.
Headphones AKG K 315. Sensitivity - 126 dB, impedance - 32 Ohm, maximum input power - 15 mW. Power
But when it comes to power, you shouldn't chase watts. Especially when the main source of music is a smartphone or portable player. With high sensitivity, a few milliwatts are enough for music to play loudly, and the amplifier of the gadget is not overloaded and economically consumes battery power. Yes, if you choose headphones with high power, the sound, perhaps (only possible), will turn out to be solid and assertive. But this will not last as long as you would like - the battery of the gadget under such a load will start to discharge rapidly. Moreover, it is not uncommon for the built-in amplifier to simply not cope with powerful headphones. As a result, you will not hear a good sound (loose shallow bass), and you will get distortions at a volume above average.
For headphones used at home, high power is no longer a problem, as they are supposed to be used with a stationary amplifier. Then high power will contribute to high sound quality.
Beyerdynamic DT 1350 headphones. Sensitivity - 129 dB, impedance - 80 Ohm, maximum input power - 100 mW Resistance
Another factor that significantly affects the sound quality, power consumption and, in general, determines the compatibility of headphones with the amplifier part is impedance. From the point of view of physics, impedance is somewhat different from the more understandable term "resistance", but from a consumer point of view, it is not so important, therefore, on the packaging of headphones it is quite possible to find such a spelling.
Any amplifier has a certain range of loads with which it is able to work in optimal mode. The impedance value of the headphones, measured in ohms, respectively, determines the operating mode of the amplifier. In portable equipment, amplifiers are usually designed to work with an impedance of 16 to 32 ohms. Therefore, these are the numbers you will find on most headphones. However, it is quite acceptable to use headphones with an impedance of 40-60 ohms with portable equipment. The fundamental difference is that the latter will require more power to operate, which means that the battery consumption will increase. Also remember that if the impedance of the headphones is significantly different from the recommended impedance, the amplifier will operate in a “freelance” mode, which can result in distortion and overall degradation of sound quality. And in extreme cases, it will also lead to failure of the amplifier or headphones.
Denon AH-C250 headphones. Sensitivity 109 dB, impedance 87 ohms, maximum input power 100 mW High impedance headphones, whose impedance is in the hundreds of ohms, should be used only with stationary amplifiers. Most often, high-impedance headphones are made for professional purposes, although they can also be found among expensive high-end models for household use.
Caution when choosing a model for home: the impedance of the headphones must fall within the recommended load range, which is indicated in the technical data of the amplifier. In general, most headphones and amplifiers are quite clearly divided into low- and high-impedance, so there shouldn't be any special problems finding a suitable pair.
frequency range
The frequency range of headphones is probably the simplest and most understandable value. The wider it is, the better the sound quality. Factory settings outside the audible range, for example, 5 Hz - 25 kHz, indicates that the edges of this most audible range will be reproduced without much loss. Maybe because this is a simple quantity, and even with large numbers, manufacturers tend to embellish it. Standard numbers such as 20 Hz - 20 kHz are common. And no indication of under what conditions the measurements were made, not to mention the frequency response graph. It is true that there may be 20Gts, but with such a loudness that only devices in a deaf acoustic room will hear them, where, possibly (only possible), measurements were taken.
Headphones Sony MDR-1R. Sensitivity - 105 dB, impedance - 48 Ohm, maximum input power - 1500 mW, frequency range - 4-80,000 Hz Ears versus numbers
In conclusion of the review of the main characteristics, I want to save readers from one common illusion that "headphones with the same passport data sound the same." Not at all.
With the same frequency range, the same sensitivity, power and impedance, different headphones are likely to play very differently from each other. Since our impression of the sound is formed by the accuracy of the response of the emitter, the shape of the frequency response and a number of other indicators that are published by the developers extremely rarely, while others cannot be measured at all. Unfortunately or fortunately, but modern measuring devices have not yet reached those heights when they learn to perceive a musical signal in a complex way, like a person. Therefore, having studied the characteristics for compatibility with the rest of the set of equipment (source, amplifier), comparing their cost with your wallet, you still need to go and listen to them. No other way.
Impedance is the nominal impedance at the headphone input. The term impedance is borrowed from the word impedance, which translates as impedance. Often used as a synonym for headphone impedance. Impedance is a combination of resistive and reactive components, resulting in a frequency-dependent impedance level. In most cases, the graph shows low frequency resonance for dynamic headphones.
You need to choose headphones by impedance in accordance with the technique with which you are going to use these headphones. For use with portable equipment, headphones with a lower impedance should be selected, and for stationary equipment, with a higher impedance. Amplifiers for portable equipment have a tightly limited output voltage level, but as a rule, they do not have a hard current level limitation. Therefore, the probability of getting the maximum possible power for portable equipment is possible only with low-impedance headphones. In stationary equipment, as a rule, the voltage limit is not so low and high-impedance headphones can be used to obtain sufficient power. High impedance headphones are a more favorable load for the amplifier and the amplifier works with them with less distortion. Low-impedance headphones are considered to be conventionally up to 100 ohms. For portable equipment, headphones with an impedance of 16 to 32 ohms are recommended, with a maximum of 50 ohms. However, if the headphone has a high sensitivity, then a higher impedance can be used.
The volume of the headphones depends primarily on the sensitivity of the headphones, and how much power the amplifier can give depends on the resistance. For example, headphones A and B have the same sensitivity - 110 dB / mW (the sensitivity is indicated in relation to mW). A portable player develops no more than 1 V at its output. Headphones A have an impedance of 16 ohms, and headphones B have 150 ohms. For headphones A, the player will give out 62 mW, and for headphones B, only 7 mW. Accordingly, in order to get a similar volume on headphones B, you need to supply the same 62 mW that are possible at 3 V, and in our example, the player can only give 1 V. However, it is worth considering that the sensitivity can be indicated not to power, but to voltage. If for both headphones the sensitivity is indicated as for example 100 dB / V (the sensitivity is indicated in relation to IN), then regardless of their resistance, they will play equally loudly (if the amplifier's output impedance is close to zero).
The Rz curve can also detect defects and defects if the curve contains strong resonances in narrow frequency bands.
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Frequency response and SPL versus headphone impedance
The frequency response of the headphones depends on the Rz curve and the output impedance of the amplifier. The higher the output impedance of the amplifier, the more the headphone frequency response changes in accordance with the Rz curve. In the example, headphones have a sensitivity of 110 dB / V, an impedance of 20 ohms, and the peak value on the Rz graph for 60 Hz is 60 ohms.
When connected to amplifiers with different output impedances, you can see how the frequency response changes. You can see that when headphones are connected to an amplifier with an output impedance of 300 ohms, the frequency response at 60 Hz changes to 7 dB.
The frequency response is shown at different levels, in accordance with how the SPL will change when low-impedance headphones are connected to an amplifier with a given output impedance. Connecting headphones to an amplifier with an output impedance of 300 ohms will lower the SPL level by 25 dB. In this case, the output of the amplifiers was set to a 1 V rms signal level with no load (or a load above 1000 ohms). Thus, low-impedance headphones play quieter than high-impedance headphones with the same sensitivity to voltage, connected to an amplifier with a high-impedance output impedance at the same volume control.
The dependence of the amplitude drop in dB depending on the ratio of the value of the internal resistance of the amplifier to the value of the load Rz at a particular frequency can be estimated in the graph below.
You can see that if, for example, an amplifier has an internal resistance of 50 ohms, and without load it produces a certain signal level, then when you connect headphones with a resistance of 25 ohms, we get the ratio of the amplifier resistance to the load equal to 2, and the amplitude drop in dB will be about 10 dB ... If the headphones have a 50 Ohm impedance, then the ratio is 1, and the amplitude drop is already 6 dB, and if the headphones have a 100 Ohm resistance, then the ratio is 0.5 and the amplitude drop will be 4 dB.
However, it is more interesting how the Rz graph will affect the final frequency response without taking into account SPL. Let's look at a small example.
Let's mark the maximum and minimum values \u200b\u200bon the Rz chart. We get 150 ohms at the maximum and 40 ohms at the minimum. Let's take the internal resistance of the amplifier as 60 Ohm. We get two ratios of resistances, internal amplifier to Rz, these are 60/150 \u003d 0.4 and 60/40 \u003d 1.5.
We get crossings of 3 and 8 dB. Their difference is 5 dB.
Now, for this case, the difference between the minimum and maximum will be 5 dB. Similarly, you can calculate for other values \u200b\u200bof the output resistance. For 0 Ohm we get 0 dB, for 25 Ohm we get 3 dB, for 100 Ohm - 6.5 dB, and for 300 Ohm - 9 dB.
The value of the data indicated by the manufacturer on the packaging with the headphones, as a rule, will not tell the ordinary consumer about anything, therefore many sales consultants, taking advantage of the buyer's ignorance, with ease, "hanging noodles", melt the stale goods. To prevent this from happening to you, you should learn to understand the main technical parameters of the headphones and their meaning yourself.
Frequency characteristics without an indication of the harmonic distortion are worthless, and an even frequency response curve does not at all guarantee high sound detail.
Headphone frequency range and its meaning.
It is generally accepted that the higher the frequency range limits, the better the sound quality. But as we know from a biology textbook, a person is able to distinguish sound in the range from 20 Hz to 20 kHz. Then why do manufacturers of various audio devices produce products with frequencies exceeding the audible area of \u200b\u200bthe human hearing aid two to three or more times higher?
If in the frequency characteristics of your favorite headphone model you see values \u200b\u200bthat exceed the limits of the audible region, it is rather a plus than a minus. Such speakers are capable of operating not only in a narrow boundary mode, but also have additional potential for more accurate, distortion-free transmission of audible frequencies.
Speaker size and headphone power.
The diameter of the speaker is only its size and nothing more, but for some reason many buyers are consciously or subconsciously convinced of the relationship between the size of the driver (aka a speaker) and the sound quality of acoustics.
The characteristic of the size of the speaker is meaningless; in fact, it is a marketing ploy designed for the stereotype of an unenlightened buyer.
The power of the acoustics is important when choosing. This parameter tells us about the output power of the speakers and affects their volume. The higher the power value of the headphones, the “juicier, brighter” sound, more bass and more accurate interpretation.
High power headphones from 2000 mW and above will drain the battery of your portable device much faster. If the sound source exceeds the maximum capacity of the headphones, they may be damaged. Consider these nuances when choosing.
What does the sensitivity of the headphones affect?
My answer is short - the sensitivity parameter is responsible for the sound volume. With the same headphone power, those whose sensitivity is higher will sound louder. Focus on the sensitivity index of 90 dB and above, such devices can be considered good.
What does headphone impedance mean?
What does impedance affect or what is impedance in headphones? This technical parameter means the following: the greater the resistance (impedance)
headphones, the more powerful the input signal must be in order to swing the membrane.
Thus, for players and other portable gadgets, the acceptable headphone impedance is 16-50 ohms. More powerful headphones with an impedance of 250 Ohm will need a sound source more powerful than a regular player, of course they will work from a standard player, but you will not get a powerful sound.
There is the following pattern: the higher the resistance, the clearer and clearer the sound. Therefore, low-impedance headphones can transmit sound with distortion, and high-impedance headphones are not loud enough with a low power source of the output signal.
A good choice for a portable player and computer would be headphones with an impedance of 32-80 ohms. For more professional work in the studio, etc., the headphone impedance can be 200 ohms or more using sound amplifiers.
When choosing headphones, for example, for a player, take into account its power, for headphones with what impedance it is designed. Usually portable gadgets are designed to work with low-impedance head monitors with an impedance of 32 ohms.
AFC is the frequency response of the headphones.
Frequency response is one of the visual ways to represent the sound of head monitors in the form of a graph. As a rule, this is a curve on which you can see how certain headphones transmit frequencies. The fewer sharp bends on the graph and the further this line passes, the more accurately the monitors reproduce the original audio material. Bass lovers on the frequency response graph can understand whether these headphones are suitable for them or not, there should be a "hump" on the graph in the low frequency region. The higher the graph extends, the louder the headphone sound.
A flat frequency response line does not guarantee high sound quality. This gives us reason to believe that the sound in the headphones is balanced, in other words, the low frequencies do not roll over and do not stick out, they do not cut hearing.
Nonlinear (harmonic) distortion factor.
In Western literature, THD is usually used - the harmonic distortion coefficient, while in the domestic literature, the THD - the nonlinear distortion coefficient is traditionally preferred. This is perhaps the only parameter by which one can judge the sound quality. If you are looking for high quality headphone sound, choose models with less than 0.5% harmonic distortion. Head monitors over 1% can be considered mediocre.
Very often you will not find this indicator not on the packaging not on the official website of some manufacturers, perhaps the manufacturer has something to hide, this is a reason to think. For example, the widely advertised headphones of the Beats by Dr. Dre Studio has a harmonic distortion of 1.5% at 1kHz.
If you find this characteristic in the description of the model you like, pay attention to what frequency this indicator is indicated for. The fact is that the harmonic distortion factor is not constant over the entire frequency spectrum. Due to the fact that the human ear hears the low frequency region less clearly, harmonic distortions up to 10% are permissible in the low frequency range, but in the frequency range from 100 Hz to 2 kHz - no more than 1%.
Top headphone manufacturers
Now you know the meaning of the characteristics of the headphones and you are unlikely to buy a "pig in a poke", but still I advise you to choose head monitors of well-known brands, time-tested and proven to be good.
Here are some reliable companies: AKG, Beyerdynamics, Sennheiser, Audio-Technica, Grado, KOSS, Sony, Fostex, Denon, Bose, Shure. There are dozens of headphone models in the model range of these manufacturers, but whatever one may say, they are all made using similar technologies, therefore their accents are very similar.
Fans of classic rock should take a closer look at the KOSS models, they have a pronounced bass. Head monitors under the AKG brand are famous for their "beauty" - the detail of high frequencies. Headphones from the German company Sennheizer usually have a relatively flat frequency response, which indicates good balance without damping or bulging frequencies.
What do the letters in the name of the headphones mean?
The letter prefix in the name of the head monitors indicates design features and some technical details of the model.
Here's an example of Sennheiser's clever headphone labeling:
- CX as well as IE series - in-ear headphones;
- MX - in-ear headphones;
- HD - classic with a headband;
- RS - wireless, complete with base and headphones;
- HDR - an additional pair of wireless headphones;
- OMX - hook-type plug-in;
- OCX - in-duct with hook type;
- PMX - overhead or plug-in with an occipital arch;
- PXC - line of headphones with active noise cancellation system;
- PC - computer headsets;
- HME - headset models designed for pilots and crews of airplanes and helicopters.
If at the end of the model name you find the index "i", then before you are headphones capable of working with Apple gadgets.
The final values \u200b\u200bof the main technical characteristics of the head monitors should be as follows.
1. Speaker size doesn't matter from a technical point of view.
2. Acoustic power - The higher the power value, the "brighter" the sound, the higher the bass, the more accurate the interpretation.
3. Sensitivity - from 90 dB and above, can be called good.
4. Resistance (impedance) - for a portable player and a computer, select head monitors with an impedance of 32-80 ohms. For studio work from 200 ohms and above.
5. Harmonic distortion - high quality sound will be provided by models with a harmonic distortion of less than 0.5%. Head monitors over 1% can be considered mediocre.
Have a nice day and good luck with your choice of headphones!
They also write resistance. What it is, why is it needed, and what impedance affects, this article tells.
Note: since impedance is an impedance that includes both its active and reactive components, you need to know that most often the first - active - value is indicated on the packages. Because of this, a deviation from the declared parameters by 1-3 Ohms is considered the norm.
Which option should you prefer? What is the resistance indicator to choose? What should it be? Here the type of equipment to which the headphones will be connected and the power of its amplifier are important.
Why do we need different resistance indicators for different models?
Headphones of different types differ in the quality of sound production: high impedance ones sound a little better. But the point here is not in the resistance as such, but in the fact that the amplifier sends less current, therefore it distorts the frequency signal less.
For portable devices - mp-3 players and tablets - it is better to choose headphones that belong to the low impedance type. If the headphones will be used at home, for example, connected to a PC or sound card, high impedance models are suitable.
The fact is that portable devices have a limited voltage level at the output, but there are no restrictions on the current. Because of this, you can only “rock” the gadget to squeeze the maximum power out of it with low-impedance headphones.
The voltage of devices that belong to the stationary type is not so limited, so you can get excellent power using high-resistance models. This option will give the amplifier a more favorable load. With a high impedance headphone, there will be less distortion in this case.
Note: for a smartphone or better choose an option up to 50 ohms. A model with a larger indicator is suitable if it has a good margin of sensitivity.
The resistance itself does not affect the sound (its volume and quality), but is responsible for these parameters in conjunction with SPL. This indicator determines how loud the headphones can sound. But how much power an amplifier can deliver is the prerogative of impedance.
If you take two pairs of headphones that have the same SPL, let's say 110 decibels per megawatt, but one model is 16-ohm, and the other is 150-ohm, and connect them to a single-voltage player, then in each of the two cases the player will sound differently:
- with a low-impedance model - by 62 mW;
- with high resistance - by 7 mW.
Simply put, his amplifier will not be able to squeeze the most out of a high-impedance model.
Devices from the category of high resistance are used with and Hi-End. They connect to amplifiers or 24-bit studio sound cards. This results in a better and more balanced audio signal. For this reason, high-impedance models are used by film and TV sound engineers, DJs. They are also used for mastering and mixing of sound recordings in project studios.
Advice: a good studio option is. In addition to a decent impedance, they will please with excellent sensitivity and wide frequency range. They sound balanced and detailed.
Headphone volume and source power consumption
Since the volume depends on the resistance, this value also affects the battery consumption of the carrier: if you listen to music at the maximum, then high-impedance and low-impedance models will use up the energy of the battery or smartphone in different ways.
The higher the resistance, the longer the battery of the device will "live" on one charge, whether it be a smartphone, a player or another gadget. This is because high-impedance headphones consume less current, and this does not depend on the final actual volume.
For users of "quiet" smartphones, the choice of headphones is extremely limited, since there is only one option - low-impedance "ears". Users with gadgets that are equipped with a sufficiently powerful output (at least 3 V) have the opportunity to experiment.
There are two optimal options here:
- low resistance, but high SPL;
- less sensitive, but with higher impedance.
So, if the user changes the 16-ohm headphones to 32-ohm ones (for example, sports ones), the battery of his gadget will last longer.
Headphone models can sound good regardless of the ohm count. But a lot depends on the carrier. For a smartphone, it is better to choose a low impedance option. For the battery to last longer, a 32 ohm model will do. For mixing audio recordings, as well as mastering audio tracks and other studio work, it is worth looking at the full-size options with high impedance. If you connect a low-impedance model to studio equipment, the volume, of course, will increase, but the frequency balance may be upset.
Headphone impedance is the input impedance. Many technical and operational characteristics depend on it.
If the impedance in the headphones is low (25 ohms or less), they require less power to deliver high quality sound. These headphones are well suited for use with devices such as music players, mobile phones and other portable devices.
And if the impedance of headphones is more than 25 ohms, then they require more power for a high sound level. This resistance protects them from possible damage caused by overloads. These headphones can be used with a wide variety of audio devices. For example, these include models used for dj-ing, the nominal impedance of which is about 25-70 ohms.
If the impedance of headphones is low, they become more susceptible to damage when using more powerful amplifiers. If you, for example, plug low impedance headphones into a DJ rig and use it at full power, you will probably blow them up.
So what is the optimal impedance? Headphones that will be used to listen to audio from a portable player or laptop should ideally have an impedance of about 16-20 ohms and a sensitivity of at least 100 dB / mW. If your device meets the European standards for maximum volume, it is best to choose headphones with an impedance of 16 Ohms, since in such devices the maximum power is even less than in others.
It is important to consider the impedance of the headphones since all models have to handle different amounts of electrical energy and impedances. Each headphone model is specially calculated and calibrated to meet specific load volumes. This not only ensures the safety of using the equipment, but also extends its life span.
Earlier, in the 60-80s, high impedance headphones were often used, since the output energy of the devices of that time was extremely high. After that, resistors began to be used that lower the output voltage. In 1996, the standard for headphone impedance was set at 120 ohms. This had a significant impact on the production and development of high impedance models, but at the same time hindered further development in other directions. In 2009, the massive sale of iPods began, with the result that low impedance equipment became highly popular. Therefore, the development of low impedance headphones has received a new impetus.
So, impedance is one of, if not the most, but still important characteristics of headphones. The model you select should match the audio equipment you are using for maximum sound quality and stable, normal operation. Therefore, you should pay attention to the impedance when buying headphones and select the most suitable model to avoid rapid wear and deterioration in the quality of work.
