Why Some Audio Files Sound Better

Music, podcasts, and the background sounds in our favorite shows are all available in audio file format. But not all of these audio files sound the same. One track may come through clear and vibrant, while another is lifeless or muffled—even if they are the same track. What is it that makes some audio files sound better than others?

The issues go beyond just having great headphones. It’s how sound is captured, stored, compressed, and then played back to our ears. We will look at each piece of the puzzle.

Sound in Its Purest Form

Sound begins as a vibration in the air. Upon recording, microphones pick up these vibrations, which in turn are converted into electrical signals. In the digital world, we then see those signals turned into numbers—almost picture elements of the original wave. The more precise these pictures are, the more the digital file will sound like the live performance.

In some cases, two technical aspects have a great impact here:

• Sample Rate: How many times per second the sound wave is sampled, which is similar to frame rate in video—the higher it goes, the smoother the result.
• Bit Depth: How detailed each snapshot is, which in turn affects how we do or don’t preserve quiet whispers and loud bursts.

When we see high numbers, the file usually sounds better.

Compression: Reducing Size at a Price

Here is where the difference in sound quality becomes very noticeable: compression.

Lossy files (MP3, AAC, and the like) remove elements of the audio that may go unnoticed by the human ear. Like putting a bag in the trunk, we remove what doesn’t have to be there. The file comes out smaller, but some detail is left out.

Lossless files (WAV, FLAC, ALAC) preserve everything. They may take up more space but play back exactly as recorded.

One feels of lesser importance; the other of greater value and truer to what the artist intended.

Bitrate: The Data Detox

Another component of the puzzle is bitrate, which is the amount of data that is processed each second. We see that as bitrate increases, so does the detail. For example, a 320 kbps MP3 will sound better than a 128 kbps one, as it has less info discarded during compression.

Still, bitrate is not a cure-all for sound quality. If the base recording is poor, no matter how high the bitrate is, it will not fix that.

The Studio Factor

The making of great-quality sound for a file starts way before you hit download or stream it. In the studio, elements like mic placement and room sound, along with mix choices, play a role in the sound.

A very well-recorded track that is artfully mixed will stand out in any compressed format. But if the recording is done poorly, it will still sound muddied regardless of whether it is in MP3 or FLAC. In fact, the file format is only a mirror of what is input into it—it cannot correct poor-quality work.

Mastering: The Last Polish

Once out of the mix stage, the song goes into mastering, which is when engineers tweak the levels to get the sound to play well across many different types of speakers and headphones. Some masters may focus on natural clarity, which makes the sound very true to the original, while others may push the volume to the max.

In the case of the loudness war, while it may make tracks sound more punchy on the radio, at the same time it also dries out the sound, which in turn removes subtle details. Also, it is not uncommon for the same track to have different remasters at different times, which may sound very different.

Playback Devices Make a Difference

Even with the best audio files, cheap equipment will do them in. Factors include:

• Headphones and speakers: Higher-quality equipment reproduces a greater frequency range, which in turn makes the music sound richer.
• DACs (Digital-to-Analog Converters): Every device has to convert digital data back into sound. Some inbuilt converters are simple, while dedicated ones improve clarity.
• Environment: In a quiet, treated room you will always get out more detail from the music than in a noisy café.

That is the case of a file which may sound great on one setup and flat on another.

How We Hear: Human Factor

Also in play is psychology. We do not hear all frequencies the same, and some people are more aware of fine details than others. Musicians and trained listeners tend to notice distortions or missing elements that may go over the average listener’s head.

Also, on that note, emotion is a factor. I may prefer a song from my teen years which has worse sound quality. At times, what we feel outweighs the science.

Streaming vs. Local Files

Streaming services present a different issue. We see that for smooth playback, many platforms compress files for quick load times. Also, some services provide “high-quality” choices for the user—others will auto-adjust based on internet speed.

By contrast, when you download and play lossless files, you get the same sound quality, which in turn is free from those tradeoffs. That is also a reason audiophiles prefer personal libraries to just using streaming.

Why Differences Stand Out

Not all of us notice those differences to the same degree. On low-end earphones for the gym, a 128 kbps MP3 will do. In a quiet setting with premium headsets, though, the missing quality becomes apparent.

This subjectiveness accounts for the issue of whether or not you can tell the difference. For some, it is very clear; for others, it is not at all.

The Bigger Picture

In the end, when it comes to which audio files we prefer over others, it is a mix of science and perception. File formats, bit rates, studio techniques, playback equipment, and personal hearing all play a role.

A quality recording preserves more of the original performance. We achieve that with great mastering and equipment. But also, our emotions, memories, and environment play a role in how we enjoy it.

So yes, some audio files do in fact sound better—but which ones sound better is a matter for the listener.