With catalogs of millions of songs that can be accessed anywhere, anytime, it’s no wonder that streaming music services like Spotify and Apple Music are continuing to attract new subscribers every day. Those two services alone have nearly 50 million subscribers, and have all but ended the era of the CD in terms of the preferred way to listen to music.
Despite the popularity of streaming music, though, many end users don’t feel as if the sound quality is what it could be. This has been one of the chief complaints about digital music in general, since the process of digitizing and compressing music does result in some sound being lost. One option to help assuage this complaint is for more devices and equipment to come equipped with better digital-to-analog converters (DAC).
The Digital Music Process
Before getting into how a DAC can help improve streaming music, it’s useful to look at the process of creating digital files.
Music — in its live form — is an analog format. The signals created by the performers are received their listeners in that exact format. Analog signals are both flexible and accurate; that is why you find them being used in many devices that need to take real-world measurements, such as in thermometers and fitness trackers that measure steps.
Digital signals, on the other hand, are signals that have been converted into a binary code — essentially, a series of 0s and 1s. When a band plays and records digital, the analog signals sent out by the instruments to create sound are captured and then converted into the digital format. As one might expect, digital code is somewhat limited in that it cannot accurately capture and convert every single nuance of the music. That’s not to say that it doesn’t come close, and to the untrained ear, the difference may be undetectable.
Adding another layer to the potential dilution of the sound is the fact that when we listen to digital music, it’s converted back into an analog format; after all, we can’t hear a series of 0s and 1s. The sound of the music depends on how well the DAC in the computer, stereo, or headphones completes that process. As you might imagine, not all DACs are created equally, meaning the same song can sound vastly different between your computer’s speakers and your high-end headphones.
The Compression Problem
It’s not just the process of digital-to-analog conversion that can affect the sound of streaming music. The size of the music file makes a big difference as well.
When music is converted into streaming formats, like mp3s, the algorithm used to compress the file will remove any content in the file that it “thinks” you can’t hear. In some cases, this doesn’t make too much of a difference. In others, the process ends up removing subtle sounds and nuances in the music that make it sound richer and more complex. The smaller the file, the more these nuances are lost.
For example, when iTunes first began offering digital music, the standard for compression was 128 kbps. Now, Apple Music offers streaming music at 256 kbps, while Spotify’s tunes are streamed at 320 kbps for premium users (free users still hear music at smaller file sizes.) While there are some streaming music services that offer “lossless” sound via larger file sizes, they tend to be less popular due to their higher cost, smaller libraries, and the storage that such large files require.
Improving Sound Quality
For end users, one way to improve the sound quality from streaming music is by improving the quality of their streamed music by investing in higher-quality digital files and adjusting the settings on their computer or stereo to maximize the sound quality.
On an engineering level, though, improving the sound quality of streamed music comes down in large part to the DAC. Including a quality DAC in headphones will increase the price, but the sound quality will be significantly improved over a standard pair. Mobile device designers are also well served to improve the quality of their DACs, since most devices are only able to offer CD-quality sound, and cannot process high-resolution music files. Because audiophiles are turning to dedicated audio players or external DACs to accommodate these files and get better than average sound, upgrading the DAC in devices that play streamed music is becoming a bigger priority.
As streamed music becomes the standard for all but the most ardent audiophiles, the sound quality of those files will almost certainly improve, and the landscape for DACs will change. Until then, for the best sound, advanced digital-to-analog conversion is a requirement.