Computers have become ubiquitous in the modern world and provide us with numerous services, including multimedia tasks, where speakers are commonplace. If you've ever wondered how computer speakers work, this article is for you!
How do computer speakers work? Whether external or built-in, computer speakers work as transducers that convert the computer's audio into audible sound waves. By first converting the computer's digital audio to analog audio via a DAC, the speaker drivers (typically electromagnetic) vibrate coincidingly and emit sound.
In this article, we'll discuss the types of speakers used in computers, how computers connect to speakers (internally and externally), and how to incorporate other “non-computer speakers” into a computer setup.
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What Kind Of Speaker Drivers Are Used In Computer Speakers?
Loudspeakers are transducers that convert audio signals (electrical energy) into sound waves (mechanical wave energy). Though there are plenty of different parts in the anatomy of speakers, the critical transducer device is called the driver.
So, it's the speaker's drivers that actually act to convert audio to sound.
Computer speakers, like the vast majority of other speakers, typically utilize what is known as electrodynamic, dynamic or “moving-coil” speaker drivers.
These drivers use electromagnetic induction to convert audio into sound. We'll discuss this driver type in greater detail in the next section.
Beyond the transducer type, we can further categorize computer speaker drivers. This is generally done by size and frequency response.
The audible frequency range for human beings is universally accepted as 20 Hz to 20,000 Hz. Typical electrodynamic drivers have a difficult time covering the entirety of this range, so we sometimes have to incorporate a variety of drivers into a computer speaker system.
If you've even heard the terms subwoofer, woofer, mid-range driver and/or tweeter, you've heard of the various “subtypes” of electrodynamic drivers.
Many computer speaker systems will come with multiple speakers. Typically, this involves a stereo pair (two of the same speakers for the left and right audio channels) and perhaps a subwoofer.
A computer subwoofer will handle the low-end frequencies (often from 20 Hz to about 80-120 Hz) and tend to have a single, large driver and a dedicated amplifier.
Other speakers may have multiple drivers to produce all other frequencies. Regular woofers work well in the low-mid and mid-frequency ranges; mid-range drivers excel at mids, and tweeters cover the high-end frequencies.
A crossover will be designed into these speakers to effectively filter the incoming signal and send the proper frequency bands to their appropriate drivers.
Of course, some computer speakers rely on a single driver per speaker to produce all of, or at least the majority of, the audible spectrum.
These speakers also typically have built-in amplifiers, which we'll discuss in greater detail in the upcoming section, Amplification & Properly Driving The Speakers.
To learn more about driver types and crossovers, check out the following My New Microphone articles:
• Differences Between Mid-Range Speakers, Tweeters & Woofers
• What Is A Speaker Crossover Network? (Active & Passive)
How Do Electrodynamic Speakers Work?
As was discussed previously, electrodynamic drivers are by far the most common in computer speakers. Let's discuss how these electrodynamic speakers work, beginning with a brief overview of how they're built.
Here is a simplified cross-sectional diagram of a typical dynamic speaker driver:
As we can see, the dynamic speaker driver is made of many different components. Let's discuss the role of each part.
Diaphragm: the large, movable membrane designed to oscillate back and forth according to the audio signal waveform. As the diaphragm moves forward and backward, it pushes and pulls air, thereby producing the necessary sound waves. The diaphragm is made up of the cone and the dust cap (dome).
Cone: the thin membrane is attached to the voice coil at the inner circumference and is designed to move inward and outward along with the movement of the voice coil. It is attached to the voice coil at its centre and the surround at its outer circumference.
Dust cap (dome): keeps dust and other airborne debris out of the voice coil. To do so, it must attach to the cone and, in effect, become part of the speaker's diaphragm.
Suspension: connects the diaphragm to the housing/basket of the speaker. It allows for the proper amount of diaphragm excursion (Z-axis) while keeping the diaphragm and voice coil in their appropriate range of motion (restricting motion in the X and Y axes). The speaker suspension is made up of the surround and the spider.
Surround: the ring-shaped component that connects the cone/diaphragm to the basket/chassis of the speaker driver. It determines the limits of the diaphragm excursion and absorbs energy to reduce resonance.
Spider: the interior portion of the speaker suspension. Its main purpose is to keep the voice coil where it should be, allowing movement along the Z-axis and restrictive movement in the X and Y axes. The spider is connected to the voice coil at its interior and the basket at its exterior.
Voice Coil: a tightly wound (typically cylindrical-shaped) coil of conductive wire. It has a lead wire attached to either of its ends and becomes part of a circuit that passes the AC audio signal.
Magnetic structure: the structure that provides a concentrated permanent magnetic field in the driver and, in particular, the voice coil.
Magnet: the main source of the speaker driver's magnetic field (the pole piece extends the magnetic poles of the main magnet).
Top pole plate: extends one magnetic pole of the magnet to the exterior of the voice coil.
Yoke (bottom pole plate + pole piece): the bottom pole plate and upward-reaching pole piece are often referred to together as the yoke. This component is the back of the loudspeaker and extends the opposite magnetic pole to the interior of the voice coil.
Basket: the stationary physical housing that connects to the magnetic structure at the bottom, the surround at the top, and the spider somewhere in the middle.
So, how does this design come together to function as a speaker driver?
Let's begin with the audio signal. Note that the audio must be analog to drive the speaker, even though computers are digital devices. We'll discuss this issue later in the article in the section The Digital-Analog Conversion Process. For now, just know that the audio signal is analog, which means it's an AC electrical signal.
This AC audio signal passes through the voice coil, and a coinciding magnetic field is produced thanks to electromagnetic induction. Electromagnetic induction states that an electrical current through a conductor will produce a magnetic field. The AC, through the voice coil, then causes an alternating magnetic field.
The varying magnetic field produced in/around the voice coil interacts with the permanent magnetic field of the driver's magnets. As the voice coil's magnetic field alternates, the coil is attracted and repulsed, causing the voice coil to oscillate in a way that mimics the audio signal waveform.
The diaphragm, which is attached to the voice coil, will also move with the voice coil.
The spider restricts the voice coil motion to the Z-axis only and, combined with the surround, limits the excursion of the diaphragm.
So, the voice coil and diaphragm move according to the audio signal. The movement of the diaphragm pushes and pulls the air around it and produces increases and decreases in localized pressure, which are effectively propagated outward as sound waves.
So that answers how computer speaker transducers work.
For more related information on electrodynamic speakers, check out the following My New Microphone articles:
• Why And How Do Speakers Use Magnets & Electromagnetism?
• How Do Speakers Produce Sound? (A Helpful Beginner's Guide)
• Do Bigger Magnets Make For Better Loudspeakers?
How Do Speakers Connect To Computers?
In this section, we'll be discussing the methods by which external computer speakers connect to their computers.
There are two general connection options: wired and wireless.
Wired Computer Speakers
As the name suggests, wired computer speakers connect to one of the computer's ports via a cable/wire. Therefore, they must have a connector type compatible with the computer. Typically, this means a USB or 3.5mm “aux” connector.
USB Computer Speakers
USB carries digital audio, defined in 3 different classes named Class 1, 2 and 3.
Class 1 can send up to a maximum of 24-bit 96 kHz, while Class 2 can support up to 24-bit 192 kHz. Class 3 supports the same resolution as Class 2 but uses less power and is less susceptible to jitter and data loss.
USB computer speakers will have their own built-in DACs (digital-analog converter) to convert the digital audio sent from the computer via USB to analog audio that can be amplified, sent through crossovers (if applicable), and used to drive the speakers.
The Logitech S150 computer speakers connect via USB.
3.5mm Computer Speakers
3.5mm wired connections connect the computer speakers via the computer's “headphone jack”. These cables utilize 3.5mm (1/8″) TRS connectors to transfer unbalanced stereo audio signals, much like headphones.
In this scenario, the DAC is within the computer's sound card, which converts the computer's digital audio into analog audio right before the headphone/3.5mm jack. This analog audio is sent through the 3.5mm “aux” cable to the speaker's amp/crossover before driving the individual speakers and drivers.
Note that other wired speakers (“non-computer” speakers) can also be connected to a computer. This is commonly the case with studio monitors, which connect to the computer via a standalone audio interface.
These monitors often connect via balanced 1/4″ TRS or XLR cables, which connect to the monitor outputs of the interface. The interface then connects to the computer via USB, Thunderbolt, FireWire, etc.
The Logitech Z130 computer speakers connect via the computer's 3.5mm jack.
Wireless Computer Speakers
Bluetooth connectivity makes up the vast majority of wireless computer speaker options. Practically all computers on today's market have Bluetooth capabilities, and the technology is perfect for connecting computer speakers.
Bluetooth computer speakers receive digital audio wirelessly via the Bluetooth protocol when paired with the computer.
These speakers accept digital audio via BT wireless transmission. Though there are several data transmission methods within the Bluetooth standard, the typical BT audio transfer between a computer and its computer speakers is as follows:
- The computer's digital audio signal is encoded by a codec (typically SBC “Low Complexity Subband Code,” which is supported by all devices) in the A2DP transfer standard.
- This encoded audio signal is used as the modulating signal that modulates the Bluetooth UHF radio carrier signals.
- The radio carrier waves are transmitted wirelessly as per Bluetooth standards between the audio device’s BT transmitter and the Bluetooth speakers' BT receiver.
- The Bluetooth receiver then decodes the modulation signal from the carrier wave.
- The A2DP encoded signal is then further decoded back to the intended digital audio signal (compression losses apply when encoding and decoding the signal).
The wirelessly transmitted digital audio signal is then converted into analog by the speaker's built-in digital-to-analog converter (DAC). It's then amplified and sent through a crossover (if applicable) to drive the computer speaker drivers, which produce sound.
The Klipsch ProMedia 2.1 is a 2.1 computer speaker system (stereo pair plus subwoofer) that connects via Bluetooth.
For more information on Bluetooth speakers, connecting other speakers to computers, and standard audio jacks/plugs, check out the following My New Microphone articles:
• How Do Bluetooth Speakers Work & How To Connect Them
• How To Connect Speakers To A Computer (All Speaker Types)
• Differences Between 2.5mm, 3.5mm & 6.35mm Headphone Jacks
• Are AUX (Auxiliary) Connectors & Headphone Jacks The Same?
How Are Speakers Incorporated Into Computers?
Let's switch our focus to built-in computer speakers.
Internal computer speakers are also exclusively electrodynamic. They, too, require analog audio, which means that there must also be a digital-analog converter(s) inline between the computer's digital audio playback and its internal speakers.
Much like external speakers, internal computer speakers also require an enclosure. These enclosures are small but necessary space within the computer that allows the speaker to move and push sound waves appropriately.
This is sometimes taken for granted, but a speaker without housing or enclosure would have no directivity and would be incapable of producing adequate sound.
Additionally, these built-in speakers also need amplifiers (also built into the computer) to amplify the computer's audio signal.
The number of speakers within a given computer depends on that computer. Many internal computer speakers are set up to provide stereo sound, though the speakers are often too close and too low of quality to truly give a convincing stereo image.
The Digital-Analog Conversion Process
We've discussed DACs in several sections above, so let's now dive a bit deeper into the digital-analog conversion process.
As the name would suggest, the process involves converting digital audio to analog audio.
DACs can be found as standalone Hi-Fi devices and within dedicated studio-grade audio interfaces but are also built into USB and Bluetooth computer speakers and computer soundcards.
So, the question is: how do digital-analog converters work?
Let's frame this discussion by stating that digital audio is technically a representation of analog audio. DACs read this digital representation and convert it back to the electrical AC analog audio signal.
Analog signals are continuous waveforms between a high and low voltage with frequencies within (and sometimes beyond) the audible range of 20 Hz to 20,000 Hz.
Digital audio signals are discrete waveforms that are sampled many times per second (sample rate) and given an amplitude value per sample based on a set number of possible amplitude values (bit depth).
Typical sample rates include 44.1, 48, 88.2 and 96 kHz (samples per second). Typical bit depths include 16-bit (65,536 possible amplitudes) and 24-bit (16,777,216 possible amplitudes).
A digital-analog converter reads these digital audio signals on a per-sample basis and decodes the information to output a smooth, continuous analog signal.
• Are Loudspeakers & Monitors Analog Or Digital Audio Devices?
Amplification & Properly Driving The Speakers
As was previously mentioned, the analog signals must be amplified to drive the speakers effectively. The amplifiers that bring audio signals up to speaker level are largely known as power amplifiers.
The built-in speakers of a computer (if the computer has built-in speakers) will be driven by a built-in power amplifier. Note that these amps will not be overly powerful but are still necessary. Built-in computer power amps are often built onto a printed circuit board within or near the computer's internal sound card.
For all external computer speakers, the power amplifier will be either a separate unit (less common) or built into one of the computer speaker system's speaker units (more common).
With external computer speakers, the audio output is either digital via USB or the headphone output. With USB, the converted audio signal isn't strong enough to properly drive speaker drivers.
The 3.5mm headphone jack, which does have a built-in DAC and amplifier, is strong enough to drive headphones but is generally not strong enough to drive proper speakers.
So either way, the external speakers need a power amp. Since computer speakers are considered “consumer-grade,” they will come with their own amplifiers, keeping things simple for the consumer.
For more information on speaker amplification, check out the following My New Microphone articles:
• Why Do Speakers Need Amplifiers? (And How To Match Them)
• What Are The Differences Between Passive & Active Speakers?
Selecting The Appropriate Speakers As The Computer's Audio Output
There must be communication between the two devices for our computer speakers to produce the computer's audio effectively.
First and foremost, ensure any and all necessary device drivers are installed if you're using USB speakers. Fortunately, speakers that connect via the headphone jack and receive analog audio, as well as those that work on the Bluetooth standard, will not require drivers.
Device drivers (not to be confused with speaker drivers) are a set of files that tell a piece of hardware how to function by communicating with a computer's operating system. Many computer speaker systems are “plug-and-play” and will work with stock drivers, but some will require dedicated drivers to work with the connected computer.
Beyond that, we must ensure that the computer is outputting audio to the appropriate audio output device (in this case, the computer speakers).
Connecting Computer Speakers Via USB
When connecting via USB, make sure the connected speakers are set as the computer's audio output device.
In Mac OS, The Path To Choose The Computer Speaker As The Audio Output Is:
- -> System Preferences
- -> Sound
- -> Output
In Windows, The Path To Choose The Computer Speaker As The Audio Output Is:
- -> Control Panel
- -> Sound
- -> Playback
Connecting Computer Speakers Via Headphone Jack
When connecting via the headphone jack, make sure the speakers are connected. The computer's soundcard should automatically toggle between “Internal Speakers” and “Headphones/Speakers.”
If the computer speakers do not connect, turn them off, unplug them from the computer, and plug them back in.
If this does not work, troubleshoot your specific computer model by looking online for forums or contacting the customer service department of your computer's manufacturer.
Connecting Computer Speakers Via Bluetooth
When connecting via Bluetooth, put the speaker in pairing mode. Open up your computer's Bluetooth preferences, and select the computer speakers to pair with.
How To Connect/Pair Bluetooth Speakers To A Computer/Laptop Running Mac OS
1. Make Your Mac OS Computer Discoverable
How to make a computer/laptop running Mac OS discoverable:
- System Preferences>Bluetooth
- Click “Turn Bluetooth On”
It should read “Now discoverable as “computer_name”
2. Pair The Mac OS Computer With The Speaker
- System Preferences>Bluetooth
- Under Devices
- Click “Pair” next to “speaker_name”
3. Unpair/Disconnect The Mac OS Computer From The Speaker
- System Preferences>Bluetooth
- Under Devices
- Click the “x” next to “speaker_name”
- Click “Remove”
How To Connect/Pair Bluetooth Speakers To A Computer/Laptop Running Windows OS
The pairing process in Windows 10 is a two-way process. That is to say that both devices have to accept to be paired.
1. Make Your Windows OS Computer Discoverable
How to make a computer/laptop running Windows OS discoverable:
- Settings>Devices>Bluetooth>Manage Bluetooth Devices
- Click Turn Bluetooth On
It should read, “Your PC is searching for and can be discovered by Bluetooth devices.”
2. Pair The Windows OS Computer With The Speaker
- Settings App>Devices>Bluetooth & Other Devices
- Click Add Bluetooth Or Other Device
- Click “speaker_name”
- Control Panel>Hardware And Sound>Devices And Printers
- Click Add A Device
- Click “speaker_name”
3. Unpair/Disconnect The Windows OS Computer From The Speaker
- Settings App>Devices>Bluetooth & Other Devices
- Click “speaker_name”
- Click “Remove Device”
- Click “Yes”
Using Other Speaker Types With Computers
There are plenty of speakers on the market that are not designed specifically for computers. In fact, most professional audio, public address, high fidelity, and portable speakers are not designed specifically for computers.
So, how can we connect these other speakers to our computers?
We've already discussed how studio monitors are typically connected to computers via studio-grade audio interfaces.
Much like how Bluetooth “computer speakers” connect wireless via Bluetooth, so too do the other (often portable) Bluetooth speakers on the market, including soundbars and Bluetooth PA speakers.
High-fidelity and audiophile-grade speakers will usually connect to a computer via an equally high-end external DAC. These digital-analog converters are top-of-the-line in maintaining the truest signal possible.
Home theatre and other entertainment system speakers are generally connected to a central AV receiver or integrated amplifier. In this case, we can often connect our computer to the receiver/amp in order to effectively connect the computer to the speakers.
Connecting your computer to your car speakers is as easy as connecting your smartphone to your car. Plug it in via the auxiliary cable or use Bluetooth if possible.
• Top 8 Best Portable Bluetooth Speaker Brands On The Market
• Top 11 Best Soundbar Brands On The Market
• Top 11 Best Car Audio Speaker Brands In The World
• Top 11 Best Studio Monitor Brands You Should Know And Use
• Top 11 Best Home Speaker Brands You Should Know And Use
• Top 11 Best PA Loudspeaker Brands You Should Know And Use
• Top 10 Best Loudspeaker Brands (Overall) On The Market Today
• Top 11 Best Subwoofer Brands (Car, PA, Home & Studio)
• Top 11 Best Power Amplifier Brands In The World
• Top 11 Best AV Receiver Brands In The World
• Top 11 Best Desktop DAC (Digital-Analog Converter) Brands
• Top 9 Best Portable DAC (Digital-Analog Converter) Brands
How do we connect a microphone to a computer? Connecting a microphone to a computer requires an audio interface. Audio interfaces physically connect mics to computers and convert analog audio signals into digital info. USB mics contain simple but limited interfaces, whereas standalone interfaces can connect entire studios to a single computer.
Continue reading: How To Connect A Microphone To A Computer (A Detailed Guide)
Do audio interfaces improve computer audio? A quality audio interface will nearly always outperform a computer's built-in stock sound card in terms of audio quality. This is true in terms of digital-analog conversion (and analog-digital conversion), amplification, and latency.
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