What's the difference between 16-bit, 24-bit and 32-bit audio?

It's important to know what makes a good or bad sound. This is related to a term called bit depth, which is very commonly used today.

When someone says this is 16-bit or 24-bit audio, they are talking about the bit depth of the audio. The following is an explanation of what this term means and the answer to the question of whether to choose a higher bit depth.

What is bit depth?

Each digital sound wave is divided into samples, in the same way that a digital image is divided into samples. Each sample has a series of generated amplitudes. This range of amplitudes is called the dynamic range.

Below is an example of a 4-bit Digital to Analog Converter (DAC). Each sample is assigned a combination of 4 binary digits, corresponding to the number of output pins. Different combinations of binary digits equate to different total voltages transmitted to the speakers or headphones.

In a 4-bit DAC, 16 combinations of binary digits can be assigned, which means that there are 16 different voltages that can be transmitted to the speaker. Higher voltage means higher amplitude and vice versa.

However, higher bit depth does not mean better sound quality. A higher bit depth only has the effect of reducing digital noise. At the lower bit depth, you hear more digital noise. If you listen to music with the aforementioned 4-bit DAC, you will see a lot of noise.

What is 16-bit audio?

When it comes to listening to music, you'll want at least 16-bit audio. Even 8-bit audio has a lot of noise, as in the example below. That noticeable hiss in the background is a digital noise that appears with low bit audio.

We've enjoyed 16-bit audio for decades, because the audio on CDs is 16-bit. Here is the same music example below but rendered in 16-bit audio; no hissing sound was heard. This is because 8-bit audio has 256 combinations of binary digits, while 16-bit audio has 65,536 (exponentially increasing).

Although a lot has changed with CDs, 16-bit audio is still the common standard. A lot of media content is still delivered as 16-bit audio files. Listening to 16-bit audio is fine, but editing it can be a problem, and that's where a higher bit depth is needed.

What is 24-bit audio?

24-bit audio is a step up from 16-bit audio. People often associate bit depth with actual sound quality. So when they see 24-bit audio, they automatically assume it's clearer or higher resolution, but it's not. 24-bit audio has higher dynamic range (16,777,216 binary combinations) and reduced noise. The question is: If we can't hear the entire noise spectrum in 16-bit audio, what good is 24-bit audio?

While noise is essentially non-existent between both of these bit depths, 24-bit audio is better for studio audio editing. At higher volumes, the sound starts to get distorted. Higher dynamic range means that the sound can reach louder volume before distortion occurs. 24-bit audio is the ultimate for editing.

What is 32-bit audio? Do we really need it?

16-bit audio removes noise and 24-bit audio for better editing, so what about 32-bit audio? You get 4,294,967,296 different combinations of binary digits with 32-bit sounds, but is that really necessary? Honestly, the answer is no.

The only real benefit of 32-bit audio is enhanced editing capabilities. The difference between bit depth is very subtle and not really noticeable.

Samuel Daniel

Update 21 September 2021