What Are the Different Types of Speakers?

There is no single speaker design that is ideal for every application. A speaker designed to reproduce deep bass has very different requirements from a driver designed to reproduce high-frequency details.

For this reason, loudspeakers are commonly divided according to their frequency range, construction and intended application.

The most common types include:

• Subwoofers
• Woofers
• Midrange speakers
• Tweeters
• Full-range speakers
• Coaxial speakers
• Component speakers
• Compression drivers
• Horn drivers
• Planar and ribbon drivers
• Electrostatic speakers
• Exciter speakers

Speaker Frequency Ranges

Different speaker types are generally optimized for different portions of the audible frequency spectrum.

Frequency

20 Hz                                      20 kHz
│──────────────────────────────────────────────│
│                                              │
Subwoofer       Woofer       Mid       Tweeter
│──────────│────────────│────────│────────────│
 Low bass       Bass      Vocals    Highs

The exact operating range varies considerably between individual drivers. There is no universal frequency boundary that applies to every woofer, tweeter or midrange driver.

1. Subwoofer

A subwoofer is designed primarily to reproduce low-frequency sound. It is normally used to reproduce bass below the main operating range of conventional speakers.

Subwoofers are commonly found in:

• Home theater systems
• Car audio systems
• PA systems
• Studio monitoring systems
• High-power music systems

Because low frequencies require the movement of significant quantities of air, subwoofers generally use relatively large diaphragms and substantial mechanical excursion.

Typical Characteristics

• Large cone area
• Long voice coil excursion
• Strong mechanical suspension
• High power handling
• Designed for low frequencies

2. Woofer

A woofer is designed to reproduce low and lower-midrange frequencies. It is one of the most common speaker types in conventional two-way and three-way loudspeaker systems.

A typical two-way speaker may use a woofer for bass and midrange frequencies while a tweeter handles the high frequencies.

Amplifier
    │
    ▼
 Crossover
    │
    ├────────► Woofer
    │
    └────────► Tweeter

Woofers are available in many sizes and designs, from small drivers used in compact speakers to large drivers used in professional systems.

3. Midrange Speaker

A midrange speaker is designed primarily to reproduce the middle portion of the audio spectrum.

The midrange region is particularly important because much of speech, vocals and many musical instruments occupy this part of the spectrum.

Three-way speaker systems commonly use a dedicated midrange driver.

              ┌── Woofer
Amplifier ────┼── Midrange
              └── Tweeter

A dedicated midrange driver allows each driver to operate over a more limited frequency range.

4. Tweeter

A tweeter is designed to reproduce high-frequency sound.

Because high frequencies require rapid diaphragm movement, tweeters usually have small, lightweight diaphragms.

Common tweeter designs include:

• Dome tweeters
• Horn-loaded tweeters
• Ribbon tweeters
• Planar magnetic tweeters
• Piezoelectric tweeters

Dome Tweeter

A dome tweeter uses a dome-shaped diaphragm attached to a voice coil or motor structure.

Dome tweeters are commonly made with materials such as fabric, polymer films or metal.

       Dome
      /────\
     /      \
    /        \
   ────────────
       Coil
        │
      Magnet

The small diaphragm provides low moving mass and allows the driver to operate efficiently at high frequencies.

5. Full-Range Speaker

A full-range speaker attempts to reproduce a broad portion of the audible frequency range using a single driver.

Full-range speakers are popular in:

• Small radios
• Compact audio systems
• Portable speakers
• DIY projects
• Voice reproduction systems

The major advantage is simplicity. A single driver can eliminate the need for a multi-way crossover.

However, a single diaphragm must compromise between bass extension, high-frequency response, excursion and efficiency.

6. Coaxial Speaker

A coaxial speaker combines two or more drivers around the same acoustic axis.

A common design places a tweeter in the center of a woofer.

       Tweeter
          │
       ┌──●──┐
      /       \
     / Woofer  \
    /           \
   └─────────────┘

Coaxial speakers are widely used in car audio because several frequency ranges can be reproduced from a relatively compact location.

7. Component Speaker System

A component speaker system uses separate drivers for different frequency ranges.

A typical system may contain:

• Woofer
• Tweeter
• Passive crossover

The drivers can be positioned independently to improve acoustic imaging and frequency response.

Component systems are especially common in higher-quality car audio systems.

8. Compression Driver

A compression driver is a high-efficiency driver commonly used in professional audio systems.

Instead of using a conventional large cone, the driver usually uses a small diaphragm coupled to a horn.

Diaphragm
   │
   ▼
 Compression chamber
   │
   ▼
 Throat
   │
   ▼
 Horn
   │
   ▼
 Sound

Compression drivers can produce high acoustic output levels and are widely used in PA systems, cinema systems and other professional applications.

9. Horn Speaker

A horn is an acoustic structure that couples a driver to the air.

Horn loading can improve acoustic efficiency and control sound dispersion.

Horns can be used with compression drivers and other types of drivers.

Large horn systems are often found in professional sound reinforcement equipment.

10. Ribbon Speaker

A ribbon speaker uses a very thin conductive element suspended within a magnetic field.

The ribbon can act as both the electrical conductor and the moving diaphragm.

Magnet      Ribbon      Magnet
  │           │           │
  │           │           │
  │           │           │
  │           │           │
  └───────────┼───────────┘
              │
           Movement

The extremely low moving mass of the ribbon can provide very fast response at high frequencies.

11. Planar Magnetic Speaker

A planar magnetic driver uses a thin diaphragm containing conductive traces positioned within a magnetic field.

The magnetic force acts on the conductive pattern and moves the diaphragm.

Planar magnetic technology is commonly used in some high-frequency drivers and headphones, as well as certain full-range loudspeaker designs.

12. Electrostatic Speaker

An electrostatic speaker operates using electrostatic force rather than the conventional voice-coil motor used in a dynamic speaker.

A thin diaphragm is placed between electrically charged stators. Changes in the audio signal cause the diaphragm to move.

Stator
  │
  │
Diaphragm
  │
  │
Stator

Electrostatic speakers can have very low moving mass and can produce detailed high-frequency reproduction.

They require specialized high-voltage drive circuitry and are considerably different from conventional dynamic loudspeakers.

13. Piezoelectric Speaker

Piezoelectric speakers use the mechanical deformation of a piezoelectric material when an electrical voltage is applied.

They are commonly found in:

• Buzzers
• Alarms
• Electronic equipment
• Small signaling devices

Piezoelectric devices can be very efficient for producing simple tones and alerts, although their characteristics are different from conventional hi-fi loudspeakers.

14. Exciter Speaker

An exciter is a speaker motor designed to make the surface to which it is attached act as the diaphragm.

Instead of attaching a conventional cone to the motor, the exciter is mounted directly to a panel or other suitable surface.

Exciter
   │
   ▼
┌───────────────┐
│     Panel     │
│               │
│  Vibrates     │
│  and produces │
│     sound     │
└───────────────┘

Exciters are used in applications such as hidden speakers, furniture speakers and other unconventional acoustic systems.

15. Open-Baffle Speaker

An open-baffle system mounts the driver on a large panel without completely enclosing the rear of the driver.

The front and rear sound waves can interact with each other.

The acoustic design therefore differs significantly from a conventional sealed enclosure.

Open-baffle systems generally require careful driver selection and panel design.

16. Dipole Speaker

A dipole speaker radiates significant sound energy toward both the front and rear.

The front and rear radiation have opposite acoustic polarity.

The interaction between the front and rear waves can strongly affect the low-frequency response.

17. Line Array Speaker

A line array uses multiple drivers arranged vertically or in another controlled geometric configuration.

Line arrays are widely used for:

• Concerts
• Large PA systems
• Churches
• Theaters
• Large venues

The arrangement allows the system's acoustic coverage and directivity to be controlled more effectively over large distances.

18. Studio Monitor Driver Systems

Studio monitors commonly use separate drivers for different frequency ranges.

A typical monitor may contain:

• Woofer
• Tweeter
• Passive or active crossover
• Amplifier section in powered designs

Studio monitors are designed with particular attention to frequency response, distortion, directivity and accuracy.

Dynamic vs Other Speaker Technologies

Which Speaker Type Is Best?

There is no universally best speaker type.

The appropriate design depends on the application.

Choosing a Speaker for a DIY Project

When selecting a speaker driver for a DIY project, do not choose based only on diameter or power rating.

Important specifications include:

• Nominal impedance
• Frequency response
• Sensitivity
• Power handling
• Voice-coil diameter
• Maximum excursion
• Resonant frequency
• Electrical Q
• Mechanical Q
• Total Q
• Effective cone area
• DC resistance
• Voice-coil inductance

For enclosure design, the Thiele-Small parameters are particularly important.

Speaker Size Does Not Determine Power Handling

A common misconception is that a larger speaker is automatically more powerful.

Power handling depends on many factors, including voice-coil size, thermal design, excursion capability, suspension and magnetic structure.

A small professional driver can sometimes handle more power than a much larger low-cost driver.

Speaker Sensitivity Matters

Suppose two speakers have different sensitivities.

The more sensitive speaker can produce greater acoustic output from the same electrical power.

This is particularly important when matching drivers in a multi-way speaker system.

A tweeter that is substantially more sensitive than the woofer may require attenuation using an L-pad or another crossover-network technique.

Why Multiple Speaker Types Are Used

A single driver has difficulty reproducing the entire audible range with the same combination of low distortion, high output and wide dispersion.

A multi-way system divides the job:

Low frequencies  ──► Woofer

Mid frequencies  ──► Midrange

High frequencies ──► Tweeter

A crossover determines which frequencies are sent to each driver.

Speaker Types and Crossovers

Typical multi-way systems can be organized as follows:

Active vs Passive Speaker Systems

A passive loudspeaker receives its amplified signal through a passive crossover when multiple drivers are used.

An active loudspeaker uses electronic filtering before the power amplification stage, often with a dedicated amplifier for each driver.

Passive:

Source → Amplifier → Crossover → Drivers


Active:

Source → Electronic Crossover
                    │
             ┌──────┴──────┐
             ▼             ▼
          Amplifier     Amplifier
             │             │
             ▼             ▼
           Woofer        Tweeter

Active systems can provide greater control over driver levels, crossover characteristics and amplifier matching.

Common Speaker Problems

• Voice-coil rubbing
• Damaged surround
• Torn cone
• Loose dust cap
• Burned voice coil
• Open voice coil
• Shorted voice coil
• Damaged spider
• Loose terminals
• Magnet or basket damage

How to Test a Speaker

A basic multimeter can be used to check the DC resistance of a speaker voice coil.

A resistance reading that is completely open may indicate an open voice coil or broken connection.

A very low resistance reading may indicate a shorted coil, although the expected resistance depends on the speaker's design.

A multimeter test alone cannot determine whether the speaker has a correct frequency response or mechanical condition.

Speaker Types at a Glance

Key Takeaways

• Different speaker types are optimized for different frequency ranges and applications.
• Subwoofers are designed for deep bass.
• Woofers reproduce bass and lower-midrange frequencies.
• Midrange drivers handle the middle portion of the audio spectrum.
• Tweeters reproduce high frequencies.
• Full-range drivers attempt to cover a broad frequency range with one driver.
• Coaxial speakers combine multiple drivers around one acoustic axis.
• Compression drivers are commonly used with horns in professional audio.
• Ribbon, planar magnetic and electrostatic speakers use different motor technologies from conventional dynamic drivers.
• The correct speaker depends on the application, enclosure, frequency range, sensitivity and power requirements.