If you’ve ever seen a larger speaker producing loud sound, you’ve likely seen noticeable vibrations in the diaphragm. Speakers need to vibrate in order to produce sound waves and these vibrations are often imperceptible to the human eye and only perceptible to the human ear.
How fast do loudspeakers and headphones vibrate? To produce the entire range of audible frequencies, a loudspeaker or headphone driver must be able to produce complex vibrations in the range of 20 Hz – 20,000 Hz (cycles per second). Some drivers produce sounds outside this range while others are dedicated to producing smaller bandwidths.
In this article, we’ll discuss the vibrating frequencies of different loudspeaker and headphone drivers in greater detail while deepening our comprehension of audio and sound.
The Audible Spectrum Of Human Hearing
It is universally accepted that the range of audible frequency humans are capable of hearing spans between 20 Hz and 20,000 Hz.
As we grow older, our ears loosen up and we sustain hearing damage. If it not uncommon for a person to loose their hearing sensitivity above 16,000 Hz by the time they’re 20-30 years of age.
Human hearing is naturally the most sensitive to frequencies in the 2,000 Hz to 5,000 Hz range. This, non-coincidentally, happens to be the critical range for speech intelligibility.
Though beyond the scope of this article, the Fletcher-Munson curves (pictured below) shows us that we’re most sensitivite in the speec intelligibility range and much less sensitive at the extremes of the audible frequency range.
The key point here is that humans, by nature, have evolved to hear frequencies between 20 Hz and 20,000 Hz.
This range is important to know when recording; mixing/mastering, and playing back audio.
Audio & Sound Frequencies
Before we get started, it’s critical to note that sound and audio are made of many different frequencies. It is only the sine wave that produces a single frequency. Sound is made of a complex relationship of many different frequencies with differing amplitudes; transient characteristics, and interactions with the environment.
Therefore, loudspeakers and headphones do not typically only vibrate at a single frequency. They vibrate in complex oscillations that account for many simultaneous frequencies.
As we’ve discussed, the audible range of human hearing is defined as 20 Hz – 20 kHz. This is what is considered “sound.”
Infrasound is defined by mechanical wave energy vibrating below 20 Hz.
Ultrasound is defined by mechanical wave energy vibrating above 20 kHz.
In terms of human hearing, we’re only really concerned with sound.
Audio, which is essentially an electrical representation of sound, fits into this 20 Hz – 20,000 Hz range as well.
A lot of the audio we listen to is defined within this range, though it certainly doesn’t have to be.
Transducers that deal with audio and sound (microphones, headphones and speakers) do not necessarily have to operate in the sound frequency range either.
Many microphones, headphones and speakers respond to (vibrate at) frequencies well outside the range of human hearing.
That being said, audio signals often do not cause them to vibrate within this range. Audio mixes are often filtered at the extremes of human hearing (a high-pass filter at 20 Hz and a low-pass filter at 20 kHz) to improve the headroom of the mix.
For more detailed information on sound and audio, check out my article What Is The Difference Between Sound And Audio?
The Driver & The Vibrating Diaphragm
To truly understand how fast a loudspeaker or headphone vibrates, it’s important that we know how the vibrating parts of these transducers work.
The key transducer component of headphones and loudspeakers is called the driver. It is designed, in one way or another, to convert audio signals (electrical energy) into sound waves (mechanical wave energy).
All headphones and loudspeakers (except for the bone conduction types) utilize a movable diaphragm to effectively produce sound. This diaphragm is a very thin membrane designed to push and pull the air (or the particles of another media) around it to produce sound waves.
Related article: Complete Guide To Bone Conduction Headphones (With Examples)
It is the diaphragm of the driver that ultimately must vibrate to produce sound and so the question of “how fast do loudspeakers and headphones vibrate” is centred around how fast the diaphragm moves back and forth to produce sound.
Though there are different types of headphone and loudspeaker drivers, the moving-coil dynamic design is the most common. Let’s quickly go over this design to better understand what causes the vibrations within the vast majority of headphones and loudspeakers.
We’ll start with a simplified cross-sectional view of a moving-coil driver:
The audio signal (alternating electrical current) passed through the voice coil when the loudspeaker/headphone is connected to an audio source.
This AC signal causes a coinciding varying magnetic field in the coil. This carying magnetic field interacts with the permanent field of the magnets and causes the coil to move back and forth.
Because the coil is connected to a diaphragm, the diaphragm also moves according to the audio signal. The diaphragm, as we’ve discussed, produces the sound waves by vibrating (pushing and pulling air).
To learn more about dynamic headphones, check out my article What Are Dynamic Headphones And How Do They Work?
Regardless of the driver type (again, the exception being the piezoelectric bone conduction headphone), it is the diaphragm that vibrates to produce sound.
To learn more about all the different headphone drivers, check out my article What Is A Headphone Driver? (How All 5 Driver Types Work).
The moving-coil design is not limited to headphones and loudspeakers. It is also very common in microphones, though it works in reverse, converting sound waves into audio signals.
To learn about moving-coil dynamic microphones, please head over to my article The Complete Guide To Moving-Coil Dynamic Microphones.
Headphone & Loudspeaker Frequency Response
When it comes to calculating how fast (and slow) a headphone or loudspeaker driver will vibrate, the frequency response specification is key.
As the name suggests, frequency response refers to the frequencies the drivers are capable of producing. In other words, the frequency response tells us how fast the headphone/loudspeaker diaphragm is capable of vibrating.
Of course, an audio signal containing the frequencies in question would have to be applied to driver in order for the driver to vibrate at the given frequency. Frequency response simply tells us the sound frequencies the driver is designed to produce.
Frequency response is typically defined as a simple range from the lowest possible frequency to the highest possible frequency. Some manufacturers and a few third-party testers offer detailed graphs to show the frequency-dependent sensitivity of the drivers within their frequency ranges.
Let me repeat that it’s critical to note that sound and audio are made of many different frequencies. It is only the sine wave that produces a single frequency. Sound is made of a complex relationship of many different frequencies with differing amplitudes; transient characteristics, and interactions with the environment.
Therefore, loudspeakers and headphones do not typically only vibrate at a single frequency. They vibrate in complex oscillations that account for many simultaneous frequencies.
How Fast Do Subwoofers Vibrate?
A subwoofer (commonly referred to simply as a “sub”) is a loudspeaker designed to produce low-end sound frequencies primarily in the bass and sub-bass ranges.
These ranges are loosely defined in the following manner:
- Sub-bass: 20 Hz – 60 Hz
- Bass: 60 Hz – 250 Hz
Consumer-grade subwoofers are often designed to repoduce audio signals between 20 Hz to about 200 Hz.
Professional live sound subwoofers are often tasked with producing the chest-thumping frequencies below 100 Hz.
THX-approved systems have subwoofers designed to produce all frequencies below 80 Hz.
That is all to say that subwoofers are designed to vibrate between 20 Hz all the way to about 200 Hz depending on the model. Some models are even capable of vibrating in the infrasound range below 20 Hz.
In many cases, we can actually see the vibrations in a subwoofer driver with our naked eyes. These are the same vibrational frequencies that we see shaking the rearview mirror in vehicles that have large subwoofers.
Note that subwoofers are designed for use in multi-speaker systems to produce the low-end frequencies that normal woofers either cannot produce or cannot optimally produce.
Crossover networks are used to separate the low-end frequencies from the rest of the audio signal. These specially-designed filters send the low-end audio information to the subwoofers that are better designed to reproduce them.
Crossovers send the other frequencies to other speakers (tweeters and regular woofers) that are better suited to reproduce their respective bands.
The Klipsch Reference Series R-100SW 10″ 300W Subwoofer (link to compare prices on Amazon and B&H Photo/Video) has a 10″ subwoofer which produces a frequency response of 32 Hz – 120 Hz and is, therefore, capable of vibrating between 32 and 120 times per second.
The Klipsch THX-1200-SW (link to check the prince at B&H Photo/Video) has a 12″ subwoofer and a frequency response of 20 Hz – 200 Hz ±3dB. It can vibrate between 20 and 200 times per second.
Klipsch is featured in the following My New Microphone articles:
• Top 11 Best Home Speaker Brands You Should Know And Use
• Top 11 Best Subwoofer Brands (Car, PA, Home & Studio)
• Top 10 Best Loudspeaker Brands (Overall) On The Market Today
How Fast Do Tweeters Vibrate?
Tweeters are designed to reproduce the high-end frequencies of audio signals. Typically, tweeters are capable of producing frequencies between 2,000 Hz and 20,000 Hz.
Depending on the crossover network, the audio frequency band that is actually sent to the tweeters may have a low point much higher than 2,000 Hz.
Specialty tweeters are capable of producing frequencies well above the range of human hearing as high as 100 kHz (100,000 Hz).
That is to say, that tweeters can vibrate anywhere between about 2,000 times a second to 100,000 times a second. These frequencies are far too fast to see with the naked eye.
The Rockford Fosgate Prime R1T-S (link to check the price on Amazon) is a 1-inch tweeter speaker with a frequency response of 2,500 Hz – 22,000 Hz. It vibrates within this range of frequencies.
The DS18 TX1S (link to check the price on Amazon) is a 1.38-inch tweeter speaker with a frequency response of 2,000 Hz – 20,000 Hz.
Note that tweeters, like subwoofers, are designed to. work along with other speakers to produce the entire audible range of frequencies.
How Fast Do Woofers Vibrate?
Woofers are designed to produce sounds in the frequency band below that of the tweet and above that of the subwoofer. In many smaller multi-driver speaker designs, there is only a woofer and a tweeter. The sub is typically built into its own separate unit.
A woofer’s typical range is from <50 Hz – 100 Hz to about 2,000 Hz – 5,000 Hz. Again, this depends on the speaker’s design and whether the speakers are designed to work with a sub.
So woofers, generally speaking, vibrate between 50 to 5,000 times per second.
The Goldwood Sound GW-6028 (link to check the price on Amazon) is a 6.5-inch woofer with a frequency response of 29 Hz – 4,800 Hz.
How Fast Do Mid-Range Speaker Woofers Vibrate?
Midrang woofers are designed to be slightly larger that tweets and smaller than standard woofers.
The midrange speaker is typically tasked with producing frequencies from about 300 Hz – 500 Hz to about 5,000 Hz – 6,000 Hz.
So these mid-range speakers generally vibrate in a large range between 300 to 6,000 vibrations per second.
Mid-range woofer tend to only be included in more evolved loudspeaker designs that incorporate 4-way crossover systems.
The Pyle PDMR5 (link to check the price on Amazon) is a 5-inch mid-range speaker that has a frequency response of 450 Hz – 7,000 Hz.
What About Full-Range Speakers?
Full-range speakers are designed to vibrate across the entire audible spectrum from 20 Hz – 20,000 Hz. They may even extend their frequency response beyond the audible range of human hearing.
Oftentimes full-range speakers are made from combining the speaker-types listed above.
Even electrostatic and Magnepan (ribbon) speakers, which are capable of producing very wide frequency bands, are typically designed with a separate moving-coil subwoofer to achieve that full range in the low-end.
How Fast Do Headphone Drivers Vibrate?
Nearly all high-quality headphones can produce frequencies between 20 Hz and 20,000 Hz. Many headphone specifications sheets claim frequency responses the extend beyond the audible range of human hearing.
Different headphone types tend to have different frequency response ranges, generally speaker. Let’s have a look at a few different headphone types and an example of each type that represents the typical frequency range:
- Moving-coil dynamic headphones
- Planar magnetic headphones
- Balanced armature earphones
- Electrostatic headphones
Moving-Coil Dynamic Headphones
Quality moving-coil dynamic headphones are typically capable of producing the entire range of audible frequencies and many have responses that extend beyond the low and high ends of the audible range.
The Sennheiser HD 280 Pro (link to compare the prices on Amazon and B&H Photo/Video) is a moving-coil dynamic headphone that has a frequency response of 8 Hz – 25,000 Hz.
Planar Magnetic Headphones
Planar magnetic headphones are typically capable of producing sound frequencies well beyond the low and high ends of the human hearing spectrum.
The Audeze LCD-4 (link to compare prices on Amazon and B&H Photo/Video) is a planar magnetic headphone that has a frequency response of 5 Hz – 50,000 Hz.
Audeze is featured in My New Microphone’s Top 13 Best Headphone Brands In The World.
To learn more about planar magnetic headphones, check out my article The Complete Guide To Planar Magnetic Headphones (With Examples).
Balanced Armature Earphones
Balanced armature drivers are notorious for their highly coloured and limited frequency responses. Like the full-range loudspeakers mentioned above, balanced armature earphones and in-ear monitors generally require multiple different driver to acheive a decent overall frequency response.
The Shure SE535 (link to compare prices on Amazon and B&H Photo/Video) is a balanced armature in-ear monitor that has a frequency response of 18 Hz to 19,000 Hz and depends on three different drivers to produce this extended range.
For more information on balanced armature drivers and the earphones/IEMs they are used in, check out my article The Complete Guide To Balanced Armature IEMs/Earphones.
Electrostatic headphones can quite easily produce sound frequencies outside the human range of hearing.
The STAX SR-007 Mk2(link to check the price on Amazon) is an electrostatic headphone that has a frequency response of 6 Hz – 41,000 Hz.
Stax is featured in My New Microphone’s Top 13 Best Headphone Brands In The World.
To learn more about electrostatic headphones, check out my article The Complete Guide To Electrostatic Headphones (With Examples).
Though most headphones are capable of producing frequencies beyond the limits of human hearing, many audio signals will be limited to our hearing range and, therefore, will not cause the headphones to vibrate across their entire responses.
So even though a headphone can vibrate at a certain speeds doesn’t necessarily mean that it will be vibrating at those speeds at any given time.
For an in-depth read on headphone frequency response, check out my article What Is Headphone Frequency Response & What Is A Good Range?
To learn how headphones work in more detail, check out my article How Do Headphones Work? (Illustrated Guide For All HP Types).
How Fast Do Microphones Vibrate?
Many microphones will have a diaphragm capable of vibrating across the entire range of human hearing. Some will even have a frequency response that allows them to vibrate and transduce sounds into audio above the 20,000 Hz upper limit of human hearing.
There are a few different types of microphones that have different types of frequency responses, generally speaking. Let’s have a look at these notable types and an example of each to show their typical “vibrational speeds”:
- Moving-coil dynamic microphones
- Ribbon microphones
- Condenser microphones
- Measurement microphones
Moving-Coil Dynamic Microphones
Moving-coil dynamic microphones are notoriously coloured and generally have limited frequency responses, especially in the high-end of the human hearing response.
To learn more about coloured mic frequency responses, check out my article What Are Coloured And Flat Microphone Frequency Responses?
The Shure SM58 (link to compare the price on Amazon and B&H Photo/Video) is a moving-coil dynamic microphone that has a frequency response of 50 Hz – 15,000 Hz.
Shure is featured in My New Microphone’s Top 11 Best Microphone Brands You Should Know And Use.
More information on moving-coil dynamic microphones is available in my article The Complete Guide To Moving-Coil Dynamic Microphones.
Ribbon microphones generally have gentler roll-of in the high-end compared to their moving-coil counterparts. However, it is uncommon to find a ribbon microphone that will capture all the frequencies of the human hearing range.
The Royer R-121 (link to compare the prices on Amazon and B&H Photo/Video) has a frequency response of 30 Hz – 15,000 Hz.
Royer is also featured in My New Microphone’s Top 11 Best Microphone Brands You Should Know And Use.
More information on ribbon microphones is available in my article The Complete Guide To Ribbon Microphones (With Mic Examples).
Condenser microphones are typically capable of vibrating at and reproducing all the frequencies of human hearing.
The AKG C 414 XLII (link to compare the prices on Amazon and B&H Photo/Video) has a frequency response of 20 Hz – 20,000 Hz.
AKG is another brand featured in My New Microphone’s Top 11 Best Microphone Brands You Should Know And Use.
More information on condenser microphones is available in my article What Is A Condenser Microphone? (Detailed Answer + Examples).
Measurement mics are specialized instruments used for measuring sound, infrasound and ultrasound. Their diaphragms and trasnducer elements are capable of vibrating at and measuring a wide range of frequencies.
The Earthworks M50 (link to compare prices on Amazon and B&H Photo/Video) is a measurement microphone that has a frequency response of 3 Hz to 50,000 Hz.
There are plenty of other microphoens on the market with many differen frequency responses. The mic examples given above are great represenations of their respective types.
Related article: Full List Of Microphone Types And Sub-Types (With Mic Examples)
For more information on microphone frequency response, check out my article The Complete Guide To Microphone Frequency Response (With Mic Examples).
To read more about how microphones work, check out my article How Do Microphones Work? (The Ultimate Illustrated Guide).
Can you damage speakers by playing them too loud? Yes, sending audio signals with higher voltages/levels than the speakers are designed for can lead to damage. Consistently overloading the voice coil can lead to burning it out. Overamplified signals can also lead to physical damage in the driver (tearing or separating the diaphragm and housing) especially if the enclosure isn’t vented properly.
How do you know when a subwoofer is blown? The first indicator that a subwoofer is blown is a noticeable distortion in the sound it produces. To test whether a sub is blown or not, test the coil for its resistance (<1.0 Ω or abrupts shift means it’s likely blown). Also, look for tears in the cone and test it by pushing on either side of it. If it is overly stiff or loose, there is likely an issue with the sub as a whole.