Have you ever been jamming to some good music and wondered how they work to produce those sweet soundwaves? The inner workings of a speaker may seem complex. But in all honesty, their fundamental structure is quite simple to understand, as you’ll find out below!
One common question about speakers is, “ Are speakers considered an input or an output device?” By definition, speakers are output devices because they receive input from computers and produce output in soundwaves.
If you’ve always wondered what goes on inside speakers and how they process signals and data from computers to produce some of your favorite pieces of music, then this article is just for you!
This post will talk about everything you need to know about the processes inside speakers and how they work in audio systems. So let’s get right into it!
What Are Input And Output Devices?
Input devices can be anything that inputs or “puts in” data to computers for processing. An easy example of an input device could be a microphone that feeds data to computers for processing.
Output devices, on the other hand, are devices that are on the receiving end. These devices receive processed data and signals from the computer. This data can then be converted or “put out” by output devices. A speaker is an example of an output device because they receive signals from computers.
The critical thing to remember is that the definition of input and output devices always takes the computer as the central reference point.
Even though speakers can have both input (audio signals) and output (mechanical sound waves) when you take the speaker itself as a reference point, it is still considered an output device according to the actual definition. The computer is seen as the central reference point.
What Type Of An Output Device Is A Speaker?
Most output devices are digital output devices, which means that they can process only digital signals. This is primarily because computers work with digital signals, and the output is also in the digital format.
On the other hand, speakers are exclusively analog devices, meaning they can only “understand” analog signals. This means they require using a thing called a digital to analog converter (DAC for short) to convert these digital audio signals from the computer to an understandable analog format.
This means a DAC component will always be placed anywhere between the speaker and computer and is necessary for speakers to function and create sound.
On the flip side, the opposite is required for input devices such as microphones, meaning an analog to digital converter (ADC) must be placed between the microphone and computer.
Luckily, these days almost all computers come with inbuilt devices called sound cards that function as DACs and ADCs. Because of these sound cards, computers can have speakers built-in and connect separate speakers to the PC through the headphone jacks.
What Are Digital Speakers?
These days many different kinds of speakers exist. One specific type is those marketed as “digital speakers.” As stated above, all speakers are analog devices because they require analog signals for speaker drivers to function.
“Digital speakers” are mostly a marketing tactic and don’t work with digital signals as an input, as they are traditional speakers with an in-built DAC and amplifier. Because at the end of the day, all speakers need analog signals to move the speaker cone backward and forwards.
Speakers As Transducers
Speakers belong to a group of devices known as transducers. In simple terms, transducers are devices that convert energy from one form to another.
Likewise, speakers convert audio signals into sound waves in the air. The input, in this case, is signals from the computer, and the output being mechanical sound waves being produced.
A speaker driver is the main component of loudspeakers and works as a transducer to convert energy from one form to another. Essentially, it is a simple yet effective electromagnetic motor. Headphones use similar kinds of drivers but are smaller in size.
Generally, speaker drivers are “dynamic” drivers, also known as moving coil drivers. These drivers make use of electromagnetic induction to operate. Electrical AC voltage signals are sent in through a conductive coil called the voice coil. This coil is attached to a mobile diaphragm and is placed inside a magnetic field.
As an input signal flows through the voice coil, it moves following the audio signal. This leads to the diaphragm moving accordingly as well.
Due to the movement of the diaphragm, the air is pushed in and out, leading to the production of pressure waves in the air. These pressure waves are effectively the output from speakers and are known as sound waves.
Can Speakers Be Used As Microphones?
Moving-coil speaker drivers are wired similarly to moving-coil mic cartridges, the only difference being that they are in reverse. Speakers convert audio signals into sound, while mics convert sound into audio signals. Their jobs are the exact opposites of each other, yet their design is fundamentally more or less the same.
By that logic, speakers can be considered reverse microphones or vice versa. With a little bit of ingenuity and reverse engineering, speakers can be converted to function as microphones.
It is essential to keep in mind, though, that just because something’s possible, it doesn’t necessarily mean it’s always going to be feasible.
Microphones have been specifically designed to be able to produce low-level and full-range signals. If speaker level ranges of motions were used in microphone cartridges, it would inevitably result in the microphone cartridge blowing up.
Speakers are created to produce high levels of sound and air pressure with high-level signals in a limited bandwidth range. Hence, even screaming into a speaker that is reverse engineered to work as a microphone would not give you a satisfactory output. The resulting output would be a low-level signal with inadequate response.