What is headphone impedance ? Effect of impedance on headphone sound quality!

It often happens that when we acquire our new headphones, sometimes you feel that you hear it very low, that it has problems with the volume, you can hear shrill noises, or the sound came from far away, in many such cases we noticed that the sound is very weak. But before you check your ears, I’ll tell you that the problem probably comes from the headphones.

If all the things mentioned above happen to you, the sound of the headphones is influencing something, and it is probably headphone impedance. Have you heard this before? if you have or haven’t, we have a simple and clear answer mentioned in this post on  What is headphone impedance?

The impedance is measured in ohms and impedance is the resistance that an object creates when the current passes through that same object, in other words, it is the energy or the electricity that a headphone needs, to start emitting sound, to emit music. This also depends on the frequency, but almost all manufacturers and standards stipulate their reference value as a kHz, this helps us understand that if the handset has little resistance, the electricity will pass quickly, and therefore the volume will be higher.

That is the reason why there are some technical specifications in the box of your new headphones and audio resources, some of the values that we can find are: “224 mW @ 16Ω / 200 mW @ 32Ω / 24 mW @ 300Ω”, which means that our device delivers to its 224 mW output when connected to 16Ω impedance headphones, this shows that when there is greater impedance in the headphones, more resistance will be in the transmission of energy.

Well, if you had not previously noticed the box of your headphones, I hope you do it today because when you look at the characteristics of the headphones and their technical specifications you will know what to expect from that product.

Before covering the issue of impedance, I would like to inform you about the other factors that affect the quality of sound, which you probably did not know and that will help you to make a better choice of headphones.

  • Frequency
    It is the number of repetitions of a phenomenon, in this case, the sound, per unit of time. Or in other words, it indicates the number of cycles of the repetitive wave per second.
    The frequency of the human ear, that is, everything we can hear is in a range between 20 and 20,000 Hz, everything outside this range cannot be heard. Even if you have the best ear or the most healthy ear, the sound that you will be able to perceive will be within that range. Any headset that is within the previous frequency spectrum will be enough to give all the sound you can hear. There are some headphones, of much higher quality, which have a much wider range of frequency. Some people say that although we can not hear the frequencies higher than 20,000 Hz or below 10Hz, they say they can feel them with the body, so these are also important.
  • Power
    It can be defined as the amount of energy per unit of time emitted by the headphones in the form of sound waves. The power required in the headphones is measured in milliwatts (mW), this factor is important because the intensity of the headphones depends on the power supplied by the player and the value of the impedance.
    The intensity of the sound is related to the electrical power that is allowed to reach through the sensitivity (dB). When the sensitivity is higher, a greater generated sound occurs. Now I will show you how to calculate the intensity of your devices using Ohm’s law (I = V / R), where I is (intensity), V (volts) and R (resistance).

What is the effect of impedance on headphone sound quality?

There must be a relationship between impedance, sensitivity, efficiency to mention a few factors. Depending on how each of them acts, the sound can be fantastic, good or bad. The output impedance of the player device and the impedance of the headphones must have a numerical relationship with each other. If this does not happen, it can affect the performance of the bass, maximum volume reduction, to name a few.

The effect of the impedance on the headphones directly affects the quality of the sound.

In the market you can find low-impedance headphones and high-impedance headphones, knowing their differences can allow you to know what is your best choice when choosing a headset. before you go to a sound shop to buy the most expensive headphones, first learn to differentiate between High-impedance headphones and Low-Impedance headphones.

The low impedance means the headphones will need less power to sound. That is to say that Low-Impedance Headphones will be able to work on any device, and give us a quite adequate sound volume, that is, that our mobile phones, laptop, Ipad, Ipod will be able to operate, since these devices do not have much energy, they do not emit a lot of power, so it is most appropriate to have Low-Impedance Headphones to take full advantage.

Now High-Impedance headphones, as the name implies, these headphones need a lot of energy to start emitting sound, for this type of devices, in general, you need an amplifier, to obtain a good quality sound. The signal that emits the device must first pass through the amplifier to give more power and energy, with this the headphones can work properly.

Any sound that is less than or equal to 32 Ohms is considered low impedance, and obviously those that exceed 32 Ohms are considered high impedance.

  • The disadvantage of Low-Impedance Headphones is, that it has electrical circuits that can be modified with very low electric currents and this causes interference, screeching or unwanted noise, this will deliver a sound that is not kind accurate.
  • The High-Impedance Headphones are usually used by professionals for musical production because they give a better quality sound, with more details, without interference or annoying noises, the reason is that their electric circuits have a higher impedance.

What is good headphone impedance?

One of each type of headset and its characteristic impedance will be shown in this paragraph. Later I will give a brief summary of each type of handset. Most In-Ear have an impedance of 16Ω, this is a good impedance and portables between 32Ω and 80Ω. In Over-ear the range is very wide, from 32Ω to 600Ω, so you have to take it into account. It does not mean that the greater impedance the headphones sound worse, much less, but you will need a suitable amplifier.

I recommend choosing headphones with a maximum impedance of 80Ω if they are going to be used in mobile devices or in PC / Mac sound cards.

The headphones are just other speakers. Knowing the impedance of a pair of headphones will answer questions such as:

  • Can I use my headphones with my smartphone?
  • Do I need an amplifier for my headphones?

It is important to answer these questions because if you do not provide the correct amount of power, your beautiful appearance headphones will not perform as well.

The impedance can affect the sound quality of the headphones, depending on the device they are connected to, causing the device to be inaudible. In general, problems are caused by high output impedance devices, such as Windows computers with a sound card of 50 Ohm or more. To avoid the previous problem and have a good impedance, we recommend following the empirical rule, known in the audio industry as the rule of 1/8, it recommends that the output impedance of the sound source must be 1/8 less than headphone input impedance. For example: if you have headphones with an input impedance of 32 Ohms, the output impedance of the audio source must be 4 Ohms or less.

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What is headphone sensitivity and impedance?

Sensitivity is one of the determining factors when adjusting the appropriate volume. Sensitivity is defined as the ability of headphones to convert the power into audible sound. This indicates that when the value of the sensitivity is higher, the headset will sound higher with the same electrical charge.

The unit of measurement of the sensitivity is in decibels, let me give you an example, an airplane taking off at an airport, if we stand right next to it, the noise generated is approximately 120 decibels, this range seriously damages the ears. In a nightclub, the maximum volume can be about 110 decibels, the barking of a dog is 100 dB, the sound of a full retentive is about 85 dB and a normal talk goes from 60 to 70 Db, because of this I can recommend that headphones that are in the range of 110 decibels, will have enough volume to enjoy music and in such a way that does not damage the ear. More of the above-mentioned range can begin to damage our ears.

Both factors indicate the power and how loud the headphones will sound.

If you tend to listen to music while you are in the bus going home and you want to isolate yourself from external noise, we recommend you to use headphones that completely cover your ear to help suppress external noise, although no all earphone isolates external noise entirely.

When a headset has a very high sensitivity it can indicate that it is more prone to produce distortions or undesired effects at high volumes, although this is relative and depends on many other factors; A headset can have a good sensitivity and yet a low degree of distortion, is the case that is happening with many magnetic headphones that are coming out recently.

Thus, headphones with a high sensitivity will sound louder at equal power than headphones with a lower sensitivity; joining this with the impedance of headphones, for example having a headset with 16Ω and 105dB / mW sensitivity and others with 32Ω and 108db / mW, and depending on where we connect the second one can sound the same or even higher, despite having twice the impedance.

Interested about the smart home and audio devices? You have heard about Alexa and Google home! If not, you must read this: we have smart speakers growing well and these are the top 2 competitiors/ecosystems to compare – alexa vs google home.

Difference between Impedance and Resistance

The electrical impedance is related to the resistance. The electrical impedance results from the sum of resistance and the reactance. The electrical resistance is the opposition to the passage of the flow of electrons that circulate through a conductive material, this means that it is the ease with which the electrons circulate. By the laws of physics, by Ohm’s law, resistance is the relation between voltage and electric current.

The resistance corresponds to the opposition of the passage of the direct current and has a unique value, while the impedance is the opposition to the passage of the alternating current, that is, it is a function of the frequency, it has different values for each frequency.

If a speaker is measured with a multimeter, the reading obtained will be lower, than the nominal impedance of the speaker, for example, a 16 ohm speaker can give us a reading of 12 ohms. This is because the multimeter measures the resistance, not the impedance.

Which headphones are a better choice?

When buying a headset you have two options, follow the recommendation of your friend or take into account the tips I have given, technical specifications and some specific details. First I want to clarify that there is no perfect headphones and that it also depends on the type of music used.

The recommendations I will make will help you have a better listening experience at home and away from home.

I’ll show a little review of the types of headphones:

  • Earphones: these are used inside the ears, their size is small, and they are included when buying portable devices such as cell phone, MP3 player, etc. They are light and comfortable.

  • In-Ear: they are similar to earphones but with the peculiarity of having a design that allows the headphone to enter the ear canal. This type of headphones, unlike the previous ones, isolate the sound from the outside. And the disadvantage is that although they bring different silicone pads (small, medium and large) they do not adapt equally well to all ears.

  • On-Ear: they have a headband to hold them and they remain on the ear. They are comfortable and offer a good relationship between comfort and sound quality.

  • Over-Ear: these are the headphones that give the best result. Comfortable to use for a long time, to have a larger size allow larger speakers and isolate the sound very well outside. Ideal to enjoy the best sound at home.

After choosing the most suitable for our situation, we review the technical specifications, most headphones offer almost the entire audible spectrum or frequency. the spectrum determines according to the range the sounds that we will be able to hear. Sounds that form what we then call bass, medium, and treble. The audible spectrum is measured in Hertz.

  • Bass, emit between 10 Hz and 256 Hz
  • Means, between 256 Hz and 2000 Hz
  • Treble, between 2000 Hz and 20000 Hz (20kHz)

Another important specification to consider is impedance and was discussed in this article. This value tells us the resistance offered by the headset to the sound that the player sends and when it is lower, we will have more volume. This data is important since it is related to the impedance of the sound source itself. This means, the impedance of the headphones should never be higher than the equipment or we will not hear anything.

Knowing the technical data that affect the quality there are a number of details that you also have to know to choose your next headphones well. These are aspects that are not indicated by numbers.

Manufacturing quality is important and analyzes the finish of the product as well. The cables including the material that surrounds the headset must be checked. It is not the same a bad quality plastic to another of higher quality and better assembly that will avoid vibrations.

Big manufacturers are always a safe bet but we have to be careful with advertising. There are brands that do a great job advertising, helped by celebrities who wear their products. It is not that they are bad products but in many of the occasions, they will be overvalued.

A clear example of this is the Beats by Dr. Dre. And I do not say that they are bad, they are good headphones but many users complain about their fragility as well as they are not suitable for all kinds of musical styles.

Considered for its excellent quality and sound, I recommend AKG, Sennheiser, TDK, Sony and Bower & Wilkins P3.

Remember, when you go to buy some new headphones. If you are going to use it both at home and on the street and you do not want to draw too much attention, I would opt for the In-ear if you move through a noisy environment or the On-ear for comfort without sacrificing quality.

Also, check the impedance and if it is suitable for the product to be used. Generally, it is not taken into account. In terms of sensitivity, it is also important, but remember that 120 dB is the sound of an aircraft engine, be careful with your ears. And do not get carried away by brands and advertising. Bet on the manufacturers of always, those who have a great experience and rarely disappoint.

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