What is Digital Signal Processing (DSP)?

Bose Quiet Comfort 45 Headphones

Look at headphones, home theater systems, or any number of audio electronics, and you’ll see the term “digital signal processing” (DSP) thrown around. Let’s explore what this term actually means and what it does to your audio.

The basics of digital signal processing explained

For a term used so casually in marketing, DSP is a very complex topic. At a basic level, all digital signal processing is taking a signal – for our purposes, an audio signal – and digitally manipulating it to achieve some sort of desired result.

It sounds simple, but the actual processing and algorithms used can be incredibly complex. A simple task like increasing the volume by a certain amount might be relatively simple, but something like adaptive noise cancellation is a much more difficult task to manage.

You will sometimes see a product like headphones described as having “a DSP”. In this case, the acronym represents a digital signal processor. All this means that the product has a chip dedicated to processing audio signals in certain ways.

Having a DSP chip is more common in devices that you wouldn’t necessarily expect to have built-in processing, like headphones. Digital signal processing is used in many other places, such as your phone or computer, but since these devices already have powerful processors built-in, there is often no need for a separate chip dedicated to digital signal processing. .

Even in systems with traditional processors, you will sometimes see DSP-specific chips included. This is because audio signal processing must occur in real time, so optimized circuitry can improve this kind of performance.

Common uses of digital signal processing

Digital signal processing is capable of doing amazing things, but it also has simple uses. When listening to a music playlist, for example, many players use DSP to ensure that there are no massive volume jumps between songs.

Another common use case for DSP is analog-to-digital conversion and digital-to-analog conversion. Often the conversion will take place in a specialized DSP chip designed specifically for this purpose, known as a DAC or AD/DA converter, depending on whether it converts only one way. Transforming real-world audio signals into digital signals is an art in itself, so you will find expensive converters on the market.

One use of DSP that you probably come across and pay attention to more regularly is for noise cancellation. A combination of external microphones on your headphones and digital signal processing cancel out the sounds around you.

The other side of the coin that also uses DSP is transparency mode, as Apple calls it. This uses the same microphones that make noise cancellation possible, but instead of canceling it, it amplifies sound, making it easier for you to hear your surroundings.

Another common use of digital signal processing is the digital equalizer. If you’ve ever used a music app on your phone or computer that lets you adjust the equalizer, that’s digital signal processing in action. When you adjust a slider, the digital processing boosts or cuts the amplitude of certain frequencies.

A final example is room correction. Many home theater systems now include a system to automatically adjust various settings to ensure the sound is optimized for the size and shape of your room. It also sets the timing for each speaker so the sound reaches your sofa perfectly in sync.

When is DSP important to you?

Asking when digital signal processing is important might seem like a weird question, but there are times when it’s crucial. For audio, there are certain aspects of the products where you should pay particular attention to the type of digital signal processing or the manufacturer of the DSP chip.

As mentioned earlier, if you’re buying a headphone amp or A/V receiver, the better the quality of the AD/DA converters, the better the sound will sound. You’ll still hear everything fine with an inferior converter, but if you’re an audio enthusiast, you won’t want to go for the cheapest components possible.

Noise cancellation is another area where the quality of DSP chips and the algorithms running on them make a huge difference. Not all noise canceling is created equal, so you should be sure to pay close attention when buying headphones or earphones.

At the same time, the built-in equalizer in headphones or various sound modes on Bluetooth speakers and A/V receivers are not as important. In many cases, these are novelty features in the first place, so the quality of processing used for these features need not be as important in your buying decisions.

Knowing what matters to you is key, so don’t worry too much about DSP features if you know you won’t be using them that often.


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