For those of us who enjoy listening to music, or watching films and TV shows on our devices, audio quality remains a top priority.
Think about the times you felt like you were transported to a different place because your headphones allowed you to hear sounds the human ear would normally not pick up.
We can agree that we often prefer a pair of headphones that:
- Can cancel background noise (for a more immersive experience),
- Is easy to bring around if needed, and
- Has the perfect balance between form and function.
In this article, we’ll dive into a more technical aspect of headphones: headphone sensitivity. What is it and why you should be mindful of it.
What is Headphone Sensitivity?
Headphones are known to be quite bulky in nature given its design of having a metal or plastic headband over your head and ear cushions on both ears, yet remain to be widely used today.
Have you ever wondered what makes the listening experience using headphones different?
We can attribute this to a headphones sensitivity level.
Headphone sensitivity refers to how effectively an electrical audio signal is converted into an acoustical one using the headphone driver.
- It indicates how loud a headphone will be based on a given level by an audio source.
- All headphones are tuned to a specific range of sound pressure level to which it is deemed sensitive.
Think of headphone sensitivity in parallelism to something or someone who is sensitive. A person or thing that is sensitive reacts a certain way when triggered.
In relation to this, headphone sensitivity indicates the sound pressure levels a pair of headphones can handle.
Headphones with high sensitivity will play sound a lot louder than low sensitivity headphones.
All About Headphone Impedance
Headphone impedance is often confused and seen as interchangeable with a headphones sensitivity rating.
However, impedance and sensitivity are two different things.
Let us give you a short background on the mechanism inside your headphones that makes it possible for electrical energy to be converted into sound.
Inside a pair of headphones, there are 3 components: a magnet, voice coil, and diaphragm. These three function to turn analog signals into something the human ear can hear.
The voice coil is wrapped to form a coil; the thinner it is, the higher the impedance values a headphone has. And a thicker coil means a lower impedance rating.
This rating is measured in Ohms.
To obtain maximum quality sound reproduction, it is key to have headphones and source impedance MATCHING with one another.
In short, impedance is the resistance to an electrical current. As it increases, headphone amplifiers are needed.
Headphones with Low Impedance
As with other gadgets, headphones are available in various specs for different purposes.
A headphone impedance of 35-50 ohms is considered LOW. Headphone manufacturers usually use create headphones with this rate of impedance.
Lower impedance headphones will not require much output power to make it work.
That means yes, these headphones will work just fine when used with portable devices such as your laptop or smartphone.
It is best comparable to basic media players that can run on batteries since they don’t require much power.
When these match, there are fewer chances of voltage loss.
Higher Impedance Headphones
When it comes to headphones with high impedance, you would need more power to get the driver working.
Since it uses a thinner voice coil, there are more wraps around the coil, creating less air between layers and an even stronger magnetic field.
To make it work, you will need a higher power output.
Headphones like this are perfect if you are looking for something that has more range.
It provides the listener with strong detail (e.g. richer bass, hearing sounds not usually within audible range, etc.). These headphones are also referred to as mixing headphones.
These kinds of headphones have an impedance of 50-80 ohms. It is recommended to have an amplifier with you as this will definitely require a greater output voltage.
Luckily, these amplifiers are can be brought around and are accessible at electronic stores. A popular one to use is a tube amplifier.
What Happens If the Power Output of Your Amplifier Is Not Enough?
If in case the headphone amplifiers you were able to get your hands on do not produce the correct power output, then the audio signal you will hear won’t be as loud as it should be.
It is important to take note of how much power your amplifier will really need to use it to its fullest capacity.
NOTE: Load impedance is also known as input impedance, which helps power the amplifier, and eventually the headphone itself.
Check Your Headphones Impedance
It is good to know your headphone or earphone impedance so you are aware of what you can pair your headphones with.
It would be pretty upsetting to purchase headphones only to find out you need to get different headphones due to incompatibility reasons.
An example of incompatibility is if you have headphones with high impedance and only a smartphone to use it with. Your phone’s battery life will not be sufficient to power it.
Why You Should Be Aware of Headphone Sensitivity Rating
We know that headphone sensitivity describes the sound pressure level produced when a voltage level is supplied to reproduce sound.
So why should we be aware of it?
Like headphone impedance, being aware of the sensitivity rating tells you what devices can work with your listening accessory and whether or not you will need an amplifier.
When powered by the same audio source, more sensitive headphones will naturally play audio louder than those with a lower rating.
Frequently Asked Questions About Headphone Sensitivity
In case you need some additional information, here are some common questions you might be asking yourself.
Is Headphone Impedance The Same As Headphone Sensitivity?
As mentioned earlier, impedance and sensitivity are two different things.
Headphones sensitivity protects our ears from playing audio too loud for our ears to handle.
Moreover, it will not be able to produce sound at a level in which our hearing will be negatively affected.
Headphone impedance and sensitivity go hand in hand. Think of them as gasoline to a car.
Having a fixed impedance and sensitivity range will prevent your headphones from getting damaged.
These ranges affect headphone performance and are specifications you would want to take note of when it comes to choosing headphones for yourself.
What’s a Safe Headphone Sensitivity Rating?
A safe headphone sensitivity for humans to consume is within the range of 60 and 80 decibels (dB).
Those on the more dangerous side expose themselves to sound pressure levels of 90 decibels and up.
Common sensitivity values you will find range between 90 dB/mW to 110 dB/mW.
How Is It Computed?
A headphones sensitivity may be measured using this equation: decibels per milliwatt (dB/mw).
What Is Output Impedance?
If you need a headphone amplifier, you want to make sure that the output impedance of said device is only 1/8 of the impedance of your headphones.
There are three reasons why the output impedance should be a lot LOWER than the impedance of your headphones:
- To avoid reduction of signal that reaches headphones
- Minimize changes in frequency response
- And reduction of electric damping factor
Headphone frequency response is a visual representation of a headphones sound pressure level across a full frequency spectrum intended for human hearing.
- This typically ranges from 20-20,000 kilohertz (khz).
- Low frequencies sound “rumbly” at 500Hz or lower.
- Mid frequencies have a horn-sounding quality to them at 500-2000Hz.
- High frequencies can cover a wide range of sounds, like cymbals or chirping birds.
Frequency response indicates the amount of energy a full frequency range has, and allows us to get an idea of how the headphone will sound.
You would want to minimize the changes in this to avoid audio/sound distortion.
Why Do Some Headphones Have High or Low Impedance?
As all devices have differing specifications, your headphone is no exception. Each headphone is made the way it is for a reason.
High Impedance Headphones
A headphone with high impedance is of more use to someone who uses it for professional use or is an audiophile.
As mentioned earlier, it needs more power to get the driver working.
These would be great for those who listen to audio casually but are more common among those who can afford a more heavy-duty setup.
They are also at less risk of experiencing blowouts due to the fact that they can handle louder sounds.
Low Impedance Headphones
Headphones with low impedance, on the other hand, are usually your everyday earphones paired with a smartphone or laptop.
It does not require an extensive setup and can be powered by simple devices.
It is the go-to for those who engage in casual listening. It is also less costly compared to the ones with higher impedance.
NOTE: Headphone design has no correlation to its impedance or sensitivity.
What Are the Pros & Cons of Low and High Sensitivity Headphones?
When it comes to headphone sensitivity comparison, each kind goes with its own set of pros and cons.
Headphones with a lower sensitivity rating are actually more durable compared to those with higher sensitivity ratings.
This is because they generally need more power output. They almost never go above the level of sound that we can stand to listen to, given that audio coming from it is not as loud.
This kind of headphone is seen as inefficient since it requires more power from an amplifier to reach what is called ‘optimal listening levels.’
If you’re someone who doesn’t mind needing a little more help from an amplifier, it should not be a problem.
A headphone with high sensitivity ratings has better driver output all without using a lot of power.
Audio is also heard louder and could be of interest to those who really want to immerse in their music.
While it is initially a good thing, a high sensitivity headphone’s capacity to play audio at a louder level can also do harm to both the device and the listener’s ear.
It is important to listen responsibly!
NOTE: Sensitivity values vary among all headphone brands. It is advisable to look carefully at the headphone specifications of the model you are eyeing before you make a final decision.
How to Check Headphone Sensitivity
Manufacturers usually place the headphone sensitivity rating on the box of the product.
To check it manually, you may use a sound or decibel meter.
Headphone sensitivity is measured in decibels (dB) of Sound Pressure Level (SPL) per milliwatt, otherwise written as dB SPL/mW or sometimes as db/mw.
You can also refer to a headphone sensitivity comparison guide.
Headphone Sensitivity vs. Efficiency
Headphone sensitivity is not exactly equal to headphone efficiency although these two affect the same thing: sound quality.
A headphone with greater efficiency means that it requires less power to attain a certain volume level, making it more efficient.
In needing less power, you decrease the chances of sound distortion.
Headphones efficiency (sometimes referred to as power sensitivity or voltage sensitivity) is frequency-dependent and is written as dB/mW.
It will beneficial to the listener to be aware of their headphone’s sensitivity.
Whether for casual listening or professional use, it would help to know if you have headphones with a low or high sensitivity rating as that would also tell you if you need to spend more, like for a headphone amplifier.
- Lower sensitivity headphones are known to be more affordable, but you might want headphones that produce a more rich sound quality.
- Remember to test out headphones before purchasing them despite knowing their sensitivity values as each ear canal has its own unique perceived loudness.
- In addition, since the sensitivity ratings of headphones vary, it is not the sole factor for choosing a specific set of headphones, but an important thing to be aware of.
Now that you are aware of key headphone specifications, you are ready to immerse in the headphone world and choose what fits you best!