Why do you need high impedance headphones? What is the best headphone impedance?

Not everyone knows that headphone impedance represents input resistance.

It is precisely from this parameter that the others will vary technical specifications. One needs to look at the impedance value as a lower one, which is less than 25 ohms, does not need much power. It turns out that high quality was reproduced with a bang, it does not require too much energy expenditure. This device is perfect for mobile phones or players. It is clear that if you use more powerful headphones, they will require much more energy. The impedance of such products exceeds 25 Ohms. It should be noted that this resistance can in the best possible way protect against overloads. If the resistance exceeds 25 Ohms, then the range of devices with which the headphones can be used increases especially.

Headphones used by DJs require more powerful, high-impedance models. When considering devices with low impedance, it is important to note that they are more susceptible to damage, especially if powerful amplifiers are used.

What should the impedance be?

When selecting headphones, it is very important to consider which devices will be used. For example, if this is a laptop, then the resistance will be sufficient at 16 or 20 Ohms, and the sensitivity can be 100. If we are talking about European standards, then it is preferable not to take devices with a power greater than 16 Ohms. In any case, the instructions that come with the equipment indicate which headphones are best suited. If impedance is not taken into account, this can lead to dire consequences, damage to devices. Each model may have its own characteristics and different amounts of energy consumed.

It is extremely important to consider that Each headphone model is manufactured with its own characteristics. After all, the model must be adjusted to specific loads, specific amounts of energy. Thus, it is possible to provide safe use products, so you don't have to worry about it. Moreover, it would be in the interests of headphone owners to extend their lifespan, so impedance should also be taken into account. Over time, various needs for certain headphones have arisen. There was a time when high impedance was required, but since 2009, low impedance models have become popular. The fact is that iPod players were produced in large volumes, which is why such headphones were needed. Today, the market can offer a huge selection of models, among which you can find devices with different characteristics.

It should be concluded that the impedance is significant characteristic, which should be looked at when purchasing. Remember that it is important to consider what technology you are purchasing headphones for. The impedance will depend on this, since different devices can provide greater or lesser sound quality. Ensure a correctly selected model long term work.

Headphone impedance describes the resistance of headphones as a function of frequency. Unlike a resistor, headphones can have different type impedance curve.

Headphone impedance and sensitivity

Impedance indirectly affects the sensitivity of the headphones (to voltage); the lower the resistance of the headphones, the more often the sensitivity (to voltage) is higher for headphones of a given form factor (based on the diameter of the speaker membrane). High impedance headphones tend to have lower sensitivity.

The dependence of voltage sensitivity is determined by the level of current flowing through the inductor; the lower the resistance, the higher the current. When focusing on “loudness” from a freely selected source, you should pay attention to higher sensitivity to voltage and lower resistance.

When expressing power sensitivity, resistance does not affect numerical value sensitivity has no effect, and the magnitude of sensitivity to power between different headphones demonstrates mainly the overall efficiency of the system (the effect of the mass of the diffuser, the power of the magnetic system, etc.)

Low impedance headphones and portable sources

Low impedance headphones typically require high level current from the amplifier at low voltage, while high-impedance headphones require high voltage at a low current level, which destroys some stereotypes that the lower the headphone impedance, the better it is for portable devices. In fact, low-impedance headphones tend to play louder, but on the contrary, they drain the device’s battery much faster due to increased current consumption. The second unpleasant feature for low-impedance headphones and high current consumption is a heavier mode for the amplifier, which, with a large current output, amplifies the signal with a high level of distortion.

Thus, if a portable source has a low output voltage, then high-impedance headphones will play quietly, but if the output voltage of the source is about 1 V or higher, then it is wiser to use headphones of 32 ohms and higher, this will give more quality and the device’s battery will be discharged slower.

If the resistance of the headphones is low, then when choosing an amplifier you need to pay attention to whether the amplifier is designed to work directly with a low-impedance load. Phones and inexpensive players as a rule, they work with minimal distortion with loads of 100 ohms and above and at the same time do not have a high maximum output voltage, which is why low-impedance headphones sound distorted, and high-impedance headphones do not sound loud enough.

Low impedance headphones are usually the most sensitive and this sometimes leads to problems." background noise", when all the source noise is clearly audible during pauses. When using an amplifier with a high signal level in its nominal operating mode, headphones with a higher impedance will be more successful.

Dependence of headphone frequency response on impedance

The higher the resistance of the headphones and the lower the total output impedance of the amplifier, the less the frequency response of the headphones will change. It is also true that the smaller the range of changes in the impedance curve over resistance, the smaller the changes in frequency response will also be.

In other words, if the amplifier has zero resistance and the headphones are high-impedance, then the frequency response will remain unchanged. If the amplifier impedance is high and the headphone impedance is low, the frequency response will change close to the proportions of the headphone impedance curve. If the headphone impedance and output impedance are straight lines, then the frequency response will not change.

Typical headphone impedance curves and their interaction with an amplifier

Recall that there are three types of typical amplifier impedance curves:

The interaction of specific headphones with amplifier types is shown in headphone reports

Dynamic In-Ear Headphones

As a rule, such headphones have a straight impedance curve and the frequency response of such headphones changes only when connected to amplifiers with zero resistance in the mid and high frequencies and increased in the area low frequencies. When connected to amplifiers with a constant output impedance or zero, the frequency response does not change. Common resistance values ​​are 16 and 32 Ohms.

Examples

Single-driver in-ear headphones

This type of headphone has a relatively flat impedance curve in the low-frequency region and has two rises, local in the region of 1-2 kHz and a gradual rise in the high-frequency region. Thanks to these boosts, many single-driver armature headphones sound comfortable in the upper midrange and high frequencies. Only when connected to an amplifier with zero resistance, the frequency response does not change; for the two remaining types (constant non-zero resistance and zero resistance in the mid and high frequencies and with an increase in the low frequencies), the frequency response changes in proportion to the impedance curves.

Examples

Multi-driver in-ear headphones

For this type of headphones, the impedance curve of the headphones can be anything, therefore, only when connected to an amplifier with zero resistance, the frequency response does not change, for the two remaining types (constant non-zero resistance and zero resistance in the mid and high frequencies and with an increase in the low frequencies ) – The frequency response changes in proportion to the impedance curves. This type of headphone is one of the most capricious and least predictable for matching with an amplifier if there is no measurement data.

Examples

Dynamic over-ear headphones

In most cases, the impedance curve has a local rise at low frequencies and a rise at the highest frequencies. When connected to an amplifier with zero resistance, the frequency response does not change; for the two remaining types (constant non-zero resistance and zero resistance in the mid and high frequencies and with an increase in the low frequencies), the frequency response changes in proportion to the impedance curves.

Examples

• You can often come across the statement that if the resistance of the headphones and the amplifier is equal, the best combination will be obtained, because in this case, the amplifier will be able to deliver the highest power level. From a mathematical point of view, in some cases this will be the case, but in practice this is nothing more than a myth, because:
  

  • very often, with amplifiers with a resistance less than 100 Ohms, there is a current limit for a load below 100 Ohms and, accordingly, with equal resistance already maximum power may not be
  • sound quality has nothing to do with the same impedance of headphones and amplifier
  • lower amplifier impedance provides potentially greater damping
  • lower amplifier resistance has less effect on the final frequency response
  • higher impedance provides potentially lower distortion, due to less dependence on headphone inductor temperature (the main advantage of current amplifiers)

  How is impedance measured?

  To measure impedance, a signal is supplied by a chain of one headphone channel and an additional resistor, where the signal level is assessed at two points in the circuit. Based on the difference in signal amplitudes with a known resistor resistance, the resistance of the headphones at a given frequency is determined.

  
  

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  They also write resistance. This article explains what it is, why it is needed, and what impedance affects.

  Note: Since impedance is total resistance, which includes both its active and reactive components, you need to know that most often the first - active - value is indicated on packages. Because of this, a deviation from the declared parameters of 1-3 Ohms is considered normal.

  Which option should you prefer? Which resistance indicator should you choose? What should it be like? What matters here is the type of equipment to which the headphones will be connected, and the power of its amplifier.

  Why do we need different resistance values ​​for different models?

  Headphones different types differ in the quality of sound production: high-impedance ones sound a little better. But the point here is not the resistance as such, but the fact that the amplifier sends less current, and therefore distorts the frequency signal less.

  For portable devices - MP3 players and tablets - it is better to select 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-resistance 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 “boost” the gadget in order to squeeze maximum power out of it only 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 high impedance headphones, there will be less distortion in this case.

  Note: for a smartphone or is it better to choose an option up to 50 Ohms. A model with a larger indicator will be suitable if it has a good sensitivity margin.

  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 produce is the prerogative of impedance.

  

  If you take two pairs of headphones that have the same SPL values, 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 different. different:

  1. with a low-impedance model - 62 mW;
  2. with high resistance - 7 mW.

  Simply put, his amplifier will not be able to get the most out of a high-impedance model.

  Devices from the high-resistance category are used in the Hi-End. They are connected to amplifiers or 24-bit studio sound cards. This gives a higher quality and balanced audio signal. For this reason, high-impedance models are used by film and TV sound engineers and DJs. They are also used in mastering and mixing sound recordings in project studios.

  Advice: a good studio option - . In addition to decent impedance, they will delight you with excellent sensitivity and a 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 energy consumption of the carrier’s battery: if you listen to music at maximum, then high-impedance and low-impedance models will spend the energy of the battery or smartphone differently.

  The higher the resistance, the longer the device’s battery will “live” on one charge, be it a smartphone, player or other gadget. This is because high-impedance headphones consume less current, and this does not depend on the final actual volume.

  Users of “quiet” smartphones have an extremely limited choice of headphones, since there is only one option - low-impedance “ears”. Users with gadgets that are equipped with a fairly powerful output (at least 3 V) have the opportunity to experiment.

  

  There are two best options here:

  • low resistance but high SPL;
  • less sensitive, but with higher impedance.

  So, if a user changes 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 number of ohms. But a lot depends on the medium. For a smartphone, it is better to choose a low-impedance option. To make the battery last longer, a model from 32 Ohm is suitable. For mixing audio recordings and mastering audio tracks and other studio work, it’s worth taking a closer look at full-size options with high impedance. If you connect a low-impedance model to studio equipment, the volume will, of course, increase, but the frequency balance may be disrupted.

  Impedance is the nominal resistance of the headphones. If we use available analogies, an electrical wire can be compared to a hose. The current is the water in the hose, and the resistance is the narrow nozzle, which makes the water flow smaller but more powerful. The volume and sound quality depend on the resistance indicator this model will provide when connected to certain sources.

  Based on the impedance value, headphones are divided into two types: low-impedance and high-impedance. Low-impedance headphones are considered to have a resistance of up to 100 ohms, and for “plugs” - up to 32 ohms. High-impedance models - headphones with impedance from 100 to 600 Ohms.

  What does headphone impedance affect? 1.
  

  

  The lower the impedance of the headphones, the higher their sensitivity (volume).

  High-impedance headphones are very demanding; they only show their full potential with audio equipment high class, because high-end audio systems have special preamplifiers. If you connect such headphones to an average smartphone or player, they will sound quiet due to the lack of output power. 2.
  

  

  High-impedance headphones consume less energy at maximum sound than low-impedance headphones.

  But this is only significant for powerful models portable electronics. If you are buying headphones for such smartphones that are focused on playing music, they are usually capable of producing a high output voltage, it makes sense to look at expensive high-impedance headphones. However, for the vast majority of players and smartphones, headphones with an impedance of 16 Ohms are perfect. 3. Sound quality
  

  

  It's simple: high impedance headphones provide less distortion from the sound source.

  But this parameter will be important for you only if we are talking about choosing headphones for an expensive audio system. If you do not plan to connect new headphones to devices with tube amplifiers, buying models with an impedance above 100 Ohms is useless. Resume
  For players and laptops, as well as for all non- flagship smartphones You can safely choose headphones with an impedance of 16-32 Ohms and a sensitivity of 100 dB. This accessory will provide a sufficient volume level and will definitely be compatible with your device.

  2014-02-16T01:32

  2014-02-16T01:32

  Audiophile's Software

  Prologue

  Headphones typically have impedances ranging from 16 to 600 ohms (and some higher). So what is the best headphone impedance value? The answer largely depends on where you are going to connect them.

  Which one is better?

  Are low impedance headphones better than higher impedance ones? What is the optimal impedance value? Here are some important recommendations (albeit in a somewhat simplified form):

  • If you are looking for headphones for use with a portable player or laptop, you should give preference to headphones with an impedance of 16 - 32 Ohms and a sensitivity of at least 100 dB/mW. There are also higher impedance headphones, up to 80 ohms, that are sensitive enough to work with some portable devices, especially if you don't need too much volume. But in fact, the lower the impedance, the better the compatibility with battery-powered devices.
  • If you don't know the output impedance of the source device, it's best to avoid using armature headphones, as they may interact undesirably with the high output impedance, resulting in downright bad sound.
  • If your source complies with European standards maximum volume(many correspond to them modern phones, even sold outside Europe), it is all the more important to select headphones with an impedance of 16 ohms and a sensitivity of 100 dB/mW or more. European compliant devices have a lower output level than most other portable devices.
  • If you're using a dedicated headphone amplifier or DAC, check its specifications or instructions for the recommended headphone impedance range.
  • If you are looking towards headphones with a sensitivity of less than 100 dB/mW, read at least the first five paragraphs of this article.

  Different headphone impedance

  Impedance of almost all non-professional acoustic speakers lies in the range of 4 - 8 ohms. This simplifies the work of developers of amplifiers, receivers, etc., because they know almost exactly what the load impedance will be. But with headphones things are a little different. There are several standards, so impedance varies widely depending on the developer, and also depending on the devices for which these headphones are designed: portable devices, consumer, studio/professional equipment. Range - from 16 to 600 (40 times more) Ohm. This causes a significant number of compatibility issues.

  Why impedance is important

  Sources intended for headphones, for the most part, provide absolutely different meanings power with different headphone impedances. For example, the Clip+ portable player can deliver 16 mW into 16 ohms, but only 0.8 mW into 300 ohms. The FiiO E7 can deliver more than 100 mW into 16 ohms, but only 2.8 mW into 600. Some sources - for example, Mini3, FiiO E9 - are not compatible with low-impedance loads at all.

  Sufficient volume

  Most sources provide at least 5 mW of power into 16 ohms. For headphones with a sensitivity of 100 dB/mW (the recommended minimum for a portable), this will give 107 dBSPL (sound pressure), which is in the range of 105 dBSPL - 115 dBSPL, which is a sufficient volume level for most people. See More Power.

  What impedance is considered high?

  I haven't heard of any hard limits, but in most cases 100 ohms and above is defined as "high impedance". These headphones are most often not intended for portable use. Also, 32 Ohms and below can be confidently called “low impedance”; such values ​​are suitable for use anywhere. This leaves an undefined region between 32 and 100 ohms, in which other factors determine the suitability of headphones for certain purposes.

  In-ear headphones with balanced armature

  Many high-end in-ear monitors use balanced armature technology. Examples include in-ear models from Shure, Etymotic, Ultimate Ears, etc. These headphones typically have an impedance between 16 and 32 ohms, but their actual impedance varies greatly with frequency. The 21-ohm Ultimate Ears SuperFi 5, for example, varies its impedance from 10 to 90 ohms. Such impedance deviations often result in undesirable interactions with the source output impedance.

  Why does headphone impedance vary so much?

  There are many reasons for this:

  • Historical preferences- Before the advent of the first good-sounding portable devices, most high-quality headphones were connected to either a home stereo system or professional studio equipment. For reasons of simplicity and cheapness in the 60s - 80s, such devices had a high output impedance. They simply used large resistances to create a voltage drop from the outputs to the speakers (so headphones could be connected to these outputs).
  • Outdated standard from 1996- In 1996, a standard for headphone output was introduced - 120 Ohms - obviously, more than would be convenient for developers of the corresponding equipment. Subsequently, Stereophile expressed his opinion about this standard: “Whoever came up with this is clearly living in a dream world.”. Low output impedance offers many benefits, but the ill-conceived standard still continues to influence the design of high-impedance headphones.
  • High impedance is welcome for high-end headphones- IN in this case There can be several compelling arguments in favor of high impedance headphones. High impedance allows the use more turns in the speaker voice coil. This can improve the efficiency of the moving system and reduce the number of compromises required, improving the overall sound experience. Also, high-impedance headphones require less current to drive, which often leads to a reduction in various types of distortion. High impedance makes the sound of headphones less dependent on the output impedance of sources, including less sensitive to the length of a three-wire cable and the quality of the connector (jack, mini-jack, etc.). Amplifiers almost always produce less distortion on higher impedance headphones.
  • The iPod Revolution Drives Impedance Reduction- As of 2009, more than 200 million iPods had been sold. Before the iPod, there were other portable devices. You could even say that taking into account music mobile phones we have more than one billion portable devices in use. This is important because battery-powered devices cannot work properly with high-impedance headphones. Thus, development was accelerated suitable headphones with low impedance. But this goes against the first three points; So we have the high-end advantages and relics of the past against the huge marketing potential of a billion portable devices.

  What headphones can I use for my device?

  This main question which most people ask. To answer this, you need to decide on three things:

  • Power Requirements- Does the source have enough power to swing this pair headphones to a sufficient volume level? The 100 dB/mW recommendations mentioned above will most likely help answer this question. In case the headphones have lower sensitivity (or it is not specified), see the article More Power.
  • Device output impedance- Finding it out is problematic, since the output impedance of most devices is unknown. But the idea is to follow the 1/8 rule described in the article on output impedance. If you multiply the source impedance by eight, you will get the minimum load impedance that is recommended to be used with this device. The FiiO E9 amplifier, for example, has an output impedance of 10 ohms. Thus, if you want to be sure of maximum quality, it should be used with headphones with an impedance of 80 ohms or higher.
  • Source Distortions- Some sources have problems with low-impedance loads. Tube amplifiers without output transformers, for example, produce significantly more distortion with low-impedance headphones.

  Is it possible to damage something by mistake?

  Use of inappropriate of this device headphones will usually not harm anything other than the sound. However, some sources are capable of producing very large output values ​​and therefore can actually damage highly sensitive headphones. But this will only happen if you increase the volume level far beyond reasonable limits, i.e., most likely this can only happen by accident. Some headphone amplifiers have a gain switch to prevent this from happening.

  When do you need a headphone amplifier or DAC?

  Finally

  TECHNICAL PART

  Voltage and current

  To understand what impedance is, it is important to have at least a basic understanding of voltage and current. Voltage is analogous to water pressure, while current is analogous to water flow (eg gallons/minute). If you run water from your garden hose without a nozzle, you will get a large flow of water and will be able to quickly fill a bucket with it, but the pressure at the end of the hose will be almost zero. If you use a small nozzle, the pressure (voltage) will be much greater, but the flow of water will be reduced (it will take longer to fill the same bucket). These two quantities are inversely related. High pressure usually corresponds to low flow, and vice versa. The same is true for voltage/current.

  Hose attachments

  Roughly speaking, impedance is similar to the size of a hose nozzle. High impedance headphones are like a narrow ear tip. To get more water, you need more high blood pressure(voltage). Low-impedance headphones are more likely to correspond to the case of filling a bucket without a nozzle, requiring more flow and not too high pressure. Most headphone outputs work well or for the first one, or for the second case, but not for both. That's why it's important to know what you're dealing with and choose your headphones accordingly.

  Load impedance (headphones)

  Headphone impedance - why it is important, what it depends on and what it affects. How to choose headphones with the optimal impedance value.