Differences Between Mid-Range Speakers, Tweeters & Woofers

If you've ever dealt with speakers, you've likely heard the terms “tweeter,” “woofer,” “subwoofer,” and maybe even “full-range” and “mid-range.” With so much terminology (jargon and informal), it can be difficult to understand exactly what is meant when discussing mid-range speakers, tweeters and woofers.

What are the differences between mid-range speakers, tweeters and woofers? These terms refer to different driver types in speakers, each with different sizes and roles in sound reproduction (turning audio into sound). Tweeters are small and produce high frequencies; woofers are large and produce low frequencies, and mid-range speakers produce mid-range frequencies.

In this article, we'll describe the various driver types we'll encounter in speaker design right after discussing speaker driver design and overall speaker design.

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Table Of Contents

• What Is A Speaker Driver?
• How Are Speakers Designed?
• A Note On Speaker Crossovers
• 2-Way Speakers, 3-Way Speakers & More
• Woofers Vs. Mid-Range Speakers Vs. Tweeters
• What Are The Different Speaker/Driver Types?
• What Is A Super-Tweeter?
• What Is A Tweeter?
• What Is A Mid-Range Speaker?
• What Is A Woofer?
• What Is A Subwoofer?
• What Is A Full-Range Speaker?
• Honourable Mention: Rotary Woofer
• Non Moving-Coil Drivers
• Related Questions

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What Is A Speaker Driver?

A speaker driver is the transducer component responsible for converting audio signals (electrical energy) into sound waves (mechanical wave energy).

Related article: What Is The Difference Between Sound And Audio?

Many loudspeakers will have multiple drivers (often a woofer and a tweeter in two-way designs).

The vast majority of speaker drivers have an electrodynamic design. These designs include a voice coil, magnet, suspension and speaker cone/diaphragm and work on the principles of electromagnetic induction.

Let's have a look at a simplified cross-sectional diagram of an electrodynamic/moving-coil speaker driver:

The speaker driver works by having the audio signal (alternating current) pass through the conductive element (voice coil). As the AC signal passes through, it causes coinciding variations in the magnetic field in and around the voice coil.

This varying magnetic field causes the voice coil to interact with the permanent field of the magnetic structure and move.

To learn more about speakers and magnets, check out my article Why And How Do Speakers Use Magnets & Electromagnetism?

The spider suspension keeps the voice coil moving along a single axis and allows it to remain suspended in the driver.

Since the voice coil is attached to the speaker cone/diaphragm, any coil movement causes diaphragm movement. This large thin diaphragm pushes and pulls the air around it and produces sound waves that mimic the audio signal's waveform.

For more information on how speakers work as transducers of energy, check out my in-depth article How Do Speakers & Headphones Work As Transducers?

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How Are Speakers Designed?

Speakers are often designed with multiple drivers. A crossover network is generally included in the speaker design to send certain bands of frequencies to different drivers.

This is important because the electrodynamic speaker driver is, by nature, not overly effective at producing all audible frequencies (20 Hz to 20,000 Hz).

Therefore, it is to everyone's benefit that speakers have various drivers designed to effectively reproduce different bands of frequencies within the overall audio signal.

As mentioned, the woofers will cover the low-end, the mid-range speakers will cover the mid-range, and the tweeters will cover the high-end.

These bands are divided up by a crossover network that splits the audio signal and sends the different bands to their appropriate drivers.

Of course, there is much more to speaker design than what I've just mentioned. However, for the scope of this article, this is what we should know before getting into our discussion about the various driver sizes/roles/types.

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A Note On Speaker Crossovers

The different driver units are designed to produce different frequency ranges within the audible range of 20 Hz – 20,000 Hz.

Sending frequencies outside the ranges of these different drivers leads to inefficiencies within the system and can even cause damage in some cases. This is particularly true of sending powerful low-end frequencies to tweeters.

Therefore, crossover networks are implemented into speaker designs to effectively split the audio signal into different bands that are best suited to drive each of the speaker's drivers.

Passive speakers have passive crossovers that deal with speaker level signals (the power amplifier comes before the crossover).

Active speakers have active crossovers that splits line level signals to send them to individual power amplifiers before they drive the individual drivers of the speaker.

To learn more about active and passive speakers, check out my article What Are The Differences Between Passive & Active Speakers?

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2-Way Speakers, 3-Way Speakers & More

The two most common speaker designs include 2-speaker drivers (known as 2-way speakers) and 3-speaker designs (known as 3-way speakers).

The 2-way speaker will have a crossover that splits the audio into high-frequency and low-frequency bands.

Generally speaking, the highs will be sent to a tweeter, and the lows will be sent to a woofer.

The crossover point will vary from speaker to speaker but is typically around 2 kHz.

The Polk Audio S15 is an example of a 2-way bookshelf speaker.

A 3-way speaker will have a more involved crossover that splits the audio signal into 3 frequency bands: highs, mids and lows.

The highs will be sent to a tweeter; the mids to a mid-range speaker; and the lows to a woofer.

Once again, the crossover point will vary from speaker to speaker. However, they can typically be found in the range of 150 Hz – 500 Hz and 2 kHz – 5 kHz.

The Sony SSCS5 is an example of a 3-way bookshelf speaker.

There are 4-way speakers on the market that effectively take the 3-way design and add a super-tweeter to handle the highest frequencies of the audio signal.

Though the crossover between the tweeter and super-tweeter depends on the setup, the crossover could perhaps be around 10 kHz.

The Pioneer TS-A6986R is an example of a 4-way coaxial speaker.

We'll get into coaxial speakers shortly, but you can skip ahead to full-range coaxial speakers by clicking here.

Subwoofers are a popular addition to audio systems and are designed to produce the lowest frequencies (typically from 20 Hz to 80, 100 or 200 Hz depending on the setup).

• THX-approved system subwoofers: ≤20 Hz – 80 Hz
• Professional-grade live sound subwoofers: ≤20 Hz ~ 100 Hz
• Consumer-grade subwoofers: ≤20 Hz ~ 200 Hz

Subwoofers require a relatively large amount of power to produce their low-end sound frequencies. Low-end frequencies require slower speaker movement and greater speaker excursion. In addition, we naturally feel these low frequencies more than we hear them, and, therefore, the subwoofer must produce higher levels if we are to hear the low-end.

For powering reasons, many subwoofers are powered. This means they have their own dedicated built-in amplifier and crossover (essentially a low-pass filter).

Therefore, the subwoofer will not drain the main amplifier of the system (if passive speakers are used) and will be separate from the built-in amps of active speakers (if active speakers are used).

The Klipsch SPL-150 is an example of a subwoofer with a built-in Class-D power amplifier.

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Woofers Vs. Mid-Range Speakers Vs. Tweeters

Let's sum up the differences between woofers, mid-range speakers and tweeters in the following table:

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What Are The Different Speaker/Driver Types?

As a primer to this section, I'd like to mention that the electrodynamic speaker driver is not the only speaker transducer type.

There are plenty of other speaker transducer/driver types, including:

• Magnetostatic/planar magnetic
• Ribbon
• Electrostatic
• Moving-iron
• Piezoelectric
• Magnetostrictive

We'll touch on these speaker driver types in the section of this article titled Non-Moving-Coil Drivers.

However, we're not overly concerned with the various speaker transducer types. As mentioned, the electrodynamic (moving-coil dynamic) speaker transducer is the most common. We're rather interested in the different sizes and roles these individual electrodynamic drivers play in typical loudspeaker design.

So with that out of the way, we have the following general speaker driver types:

• Super-tweeter
• Tweeter
• Mid-range speaker (“Squawker” or “Midwoofer”)
• Woofer
• Subwoofer
• Full-range speaker

Let's discuss each in detail.

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What Is A Super-Tweeter?

A super-tweeter is an additional driver that helps take some of the load off of the tweeter.

It is responsible for producing the highest frequencies of the audio signal and allows the tweeter to “focus” on producing a narrower band with greater precision.

Super-tweeters are generally found in 4-way speakers along with a tweeter, mid-range speaker and woofer. However, there are also cases where a super-tweeter is used in conjunction with a tweeter and woofer in a 3-way speaker.

When included in a design, the super-tweeter is typically the smallest speaker (though it is sometimes the same diameter as the tweeter).

Like tweeters, super-tweeters do not require an enclosure to produce their full range of frequencies. That being said, rarely do we see tweeters by themselves. They are nearly always used in conjunction with woofers (which do require enclosures).

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What Is A Tweeter?

Think of a tweeter as the high-pitched tweeting of a bird.

The tweeter is the smallest driver unit in a speaker design and is responsible for reproducing the highest range of frequencies. This range is often within 2 kHz to 20 kHz though some specialty tweeters can produce sound waves as high as 100 kHz.

Note that when super-tweeters are used in the speaker design, the tweeter will have a smaller band and not have to produce frequencies up to 20 kHz.

Remember that the audible range of human hearing is universally known as 20 Hz – 20 kHz.

The overwhelming majority of tweeters are 1-inch (25 mm) in diameter. These small-diameter lightweight tweeter drivers are capable of vibrating very quickly and reproducing treble frequencies with great detail.

Larger drivers (like midrange speakers and woofers) have a much more difficult time vibrating as fast as tweeters, making tweeters the go-to drivers for high-frequency sound reproduction.

Because they are only tasked with producing high frequencies, tweeters do not rely on enclosures to produce their sound.

Tweeters are found in practically all multi-driver speakers, whether 2-way, 3-way or 4-way.

Modern tweeters often utilize a dome-shaped diaphragm to help expand the area of sound distribution and make the high frequencies less directional. By nature, lower frequencies are less directional (more omnidirectional) while higher frequencies are more directional.

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What Is A Mid-Range Speaker?

The mid-range speaker (sometimes referred to as a squawker or mid-woofer, to keep with the animal noise theme) is responsible for producing the mid-range frequencies.

Think of a squawker as the lower squawk of a larger bird.

As the name suggests, mid-range drivers are designed to produce the mid-range of the frequency spectrum—the frequency response of mid-range speakers ranges, roughly speaker, within 150 Hz to 5 kHz.

Of course, different midrange drivers will have different frequency responses and different speaker crossovers will send different frequency bands to these drivers. Therefore, it's difficult to state any specific range with confidence.

Because mid-range speakers are tasked with producing the mids, we'll generally only see them in 3-way or 4-way speakers. To produce the full range of audible frequencies, a speaker containing a midrange driver would also require a woofer to cover the low-end (which we'll get to in a moment) and a tweeter to cover the high-end.

Mid-range drivers are cherished for their ability to reproduce the mid-range frequencies, which are, arguably, the most important frequencies to human hearing.

So even though 2-way speakers (with a wafer and tweeter) are often capable of producing frequencies across the human range of audible frequencies, a mid-range speaker driver can really hone in on the mids and improve the speaker clarity and performance.

Midrange speakers are often designed similarly to woofers though smaller. Their diameters range greatly but are often between 5 and 8 inches.

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What Is A Woofer?

Think of a woofer as the lower woof of a dog.

The woofer is the larger, bassier driver in a multi-driver speaker.

Woofers are often tasked with producing frequencies from 20 Hz – 2,000 Hz. Note that the midrange speaker driver may take some load off the woofer's high-end frequency production. Similarly, a subwoofer may very well ease the production of the very low frequencies in a woofer.

Nonetheless, woofers are included in speaker design to produce the low-end and are typically joined by a tweeter (in 2-way speakers) or a tweeter and midrange driver (in 3-way speakers).

To produce the lowest frequencies, woofers need to be big. A woofer of 12-inch diameter or more is likely capable of reaching down to 20 Hz. This is why many subwoofers (which we're get to shortly) are at least this big.

That being said, we'll often have smaller woofers in professional studio monitors and rely on a separate subwoofer to produce the low-end with clarity.

Lower frequencies require larger speaker drivers. The driver must move slower and further than its tweeter counterpart. It must also push more air since lower frequencies are not heard as well as higher frequencies.

Woofers also require enclosures to help produce these low frequencies at suitable levels. The speaker enclosure is generally designed specifically to match the woofer driver.

Sealed enclosures trap the low frequencies and keep them from “escaping” through the back of the speaker. This is important for improving the directionality of the low-end since low frequencies are, by nature, omnidirectional. Sealed enclosures also provide the cleanest bass sound.

Ported speakers are designed to allow the bassy sounds to escape from the closure via carefully placed ports. These ports improve the volume of the bass and are designed to mitigate much of the phase issues that would result from the omnidirectional propagation of the bass frequencies.

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What Is A Subwoofer?

Think of a subwoofer as being “sub” or lower than a woofer.

Subwoofers are designed to produce the lowest frequencies that regular woofers cannot produce effectively.

Once again, the general subwoofer frequency responses are:

• THX-approved system subwoofers: ≤20 Hz – 80 Hz
• Professional-grade live sound subwoofers: ≤20 Hz ~ 100 Hz
• Consumer-grade subwoofers: ≤20 Hz ~ 200 Hz

Subwoofers are nearly always mounted inside their own dedicated enclosure and have their own dedicated amplifier and crossover/filter. Some subwoofers have multiple woofer drivers, but oftentimes one is enough.

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What Is A Full-Range Speaker?

Full-range speakers (often referred to as coaxial speakers) are speakers designed to produce the full range of audible frequencies.

Coaxial speakers, as the name suggests, have multiple drivers that share an axis of movement. Like the speakers mentioned above, the full-range speakers can be 2-way, 3-way or even 4-way. However, they share a single axis and are essentially designed on top of or within each other.

The woofer, midrange (if applicable), tweeter and super-tweeter (if applicable) are built into concentric circles.

Many automobile manufacturers utilize coaxial speakers since they are cheaper and easier to install.

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Honourable Mention: Rotary Woofer

A rotary woofer is a specialty type of loudspeaker that uses the motion of its voice coil to change the pitch of a spinning fan blade mechanism rather than to move a cone/diaphragm.

These woofers are rare but are capable of producing sound frequencies much lower than even the deepest subwoofers.

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Non-Moving-Coil Drivers

In an earlier section of this article, I mentioned that, although the moving-coil/electrodynamic speaker driver is the most popular, there are also other types of speaker transducers out there.

Rather than going into great detail about each type (that's for another article), I'd like to discuss the general ranges these transducers yield in their respective speaker designs.

Once again, the noteworthy alternative speaker driver transducer types are:

• Magnetostatic/planar magnetic: These speaker drivers are often full-range, capable of covering the entire audible range of frequencies.
• Ribbon: Ribbon speakers are sometimes found as tweeters in high-end studio monitors. Larger ribbon speakers have relatively poor high-end but can produce much of the audible frequency spectrum.
• Electrostatic: Electrostatic speaker drivers can easily produce the audible range of frequencies and beyond.
• Moving-iron: These primitive speaker drivers are very limited in their frequency range. That being said, utilizing several different moving-iron drivers could, in theory, produce the entire range of human hearing.
• Piezoelectric: Piezoelectric speaker drivers have relatively coloured frequency responses and cannot accurately produce the entire audible spectrum.
• Magnetostrictive: These speaker drivers have a wide range of frequency response across their many designs. There are ultrasonic magnetostrictive speakers along with full-range drivers and even subwoofers.

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Related Questions

What is the difference between coaxial speakers and component speakers? Coaxial speakers are designed concentrically with all drivers embedded within each other on the same primary axis. Component speakers have each driver in a separate location. Coaxial speakers are cheaper and easier to install, while component speakers often offer greater sound quality and flexibility.

What is better, 2-way or 3-way speakers? Though it may seem intuitive that a 3-way speaker would be better than a 2-way since its drivers are better suited to produce their intended frequency bands, there are far too many other factors that go into determining whether a speaker is “better” than another.