What is High-Resolution Audio?
High-resolution audio has been in development since the 1980s with the height of CD. As technology advances, music and other audio programming can be consumed at home like it’s coming straight from the studio. There has been some debate in defining high resolution audio, but here is the high resolution audio definition according to the DEG, CEA, and The Recording Academy:
“Lossless audio that is capable of reproducing the full range of sound from recordings that have been mastered from better than CD quality music sources which represent what the artists, producers and engineers originally intended.” (Here is the full HRA Definition Announcement.)
As music has gone digital, we have all sacrificed quality for accessibility when it comes to music. Having thousands of songs in your pocket was a dream come true. Rather than having a ton of CDs stacked somewhere, engineers had created a format to store our music library on a small portable device.
The original source file, where the music or program is first posted or released, is of the highest quality. Just because the music is in a certain file type like FLAC or WAV does not mean it is high resolution. You cannot take a compressed or low quality file and turn it into an uncompressed hi-res file. That does not bring back the original quality of the recording because the data isn’t there.
Key words with Hi-Res audio are:
- Compressed (lossy) file
- Uncompressed (lossless) file
- Bit depth
- Sampling rate (or sampling frequency)
There is a difference between music compression and music file data compression. Music compression is when audio engineers control the dynamics of the music with hardware like an audio compressor. Music file data compression removes some musical information with an encoding algorithm to reduce the file size.
Most of us are familiar with the MP3 file. This is the file you get from most digital music stores and on most streaming services like Spotify and Pandora. However, compressed music can lose the details that give vocals and cymbals that shimmer, it can smear drums to make them less punchy and leaves just what is important.
Here are some common compressed (lossy) files:
- MP3 – Most common audio file used today for music distribution and music streaming
- AAC – stands for “Advanced Audio Coding”, generally achieves better sound than mp3.
- WMA – “Windows Media Audio” format developed by Microsoft.
Compressed files permanently get rid of information that is deemed unimportant. This is done to get the audio file size down and still sound decent. Those pieces could be the sound of the room, the details of a singer’s voice or the true punch of the drums.
You can’t go from a compressed lossy file to a lossless file. Well, you can but all you would be doing is making an uncompressed file of a compressed file. It does not bring back what was missing in the original audio source.
Uncompressed lossless files are the original recording, or at least a high-resolution file of the recording. There are a couple of options when you buy high resolution music, here are some of the file formats to choose from:
- WAV – this is the main lossless audio format for Windows computers.
- AIFF – this is the main lossless audio file format for Apple® computers.
- DSD – This format samples the audio in an entirely different way from PCM formats like the other files listed here.
- FLAC – this lossless audio file format is becoming increasingly popular, especially for high-quality music streaming.
Bit depth is a measurement of how much dynamic range the audio file is capable of capturing.
Let’s use the CD as an example. The standard bit depth for CDs is 16-bit. This means that music on a CD can reproduce a 96dB signal-to-noise ratio (each bit measures up to about 6dB, so 16 bits x 6dB = 96dB of range). A signal-to-noise ratio is the measure of the signal strength versus how much background noise is present in the recording. A higher bit depth also gives a recording a larger range of volumes to be captured.
Why is this important? Music recorded at 16-bit can present challenges for engineers to capture sounds without clipping or adding unwanted noise. Engineers and producers now record with 24-bit audio since it can capture sounds with less noise and chance of clipping since it has more headroom than 16-bit recordings. Also, for archiving purposes, having a high resolution file means you can create a smaller-sized file if you want with the least amount of signal degradation.
Getting 16-bit files can mean the song was recorded in 24-bit, then truncated to 16-bit. You get the accurate recording of 24-bit audio, just in a 16-bit file. Bringing the bit depth down from 24-bit to 16-bit involves a process called dithering, which adds noise to the file to randomize the errors that occur when truncating. This process in the end sounds like white noise was added to the signal. It is not really audible to most, but still present. At least you know when getting a hi-res 24-bit file that it is indeed a 24-bit audio file.
The sampling rate, or sampling frequency, means how many times per second the audio will have a “snapshot” taken of it. The standard for CD is 44,100 (44.1kHz sampling frequency, which is considered optimal for recording the human range of hearing) samples per second. So the standard CD quality is: 16bit/44.1kHz.
Think of it like this, when you watch an old movie with a low frame rate you can tell that the movie is a bunch of individual pictures that fool your eye into thinking it is one continuous motion. The higher the frame rate, the more it fools your eye. It’s similar with audio.
These numbers represent how accurate the digital recording was. Digital music is a representation of sounds that we hear in the real world. It does not perfectly capture the original sound when recorded digitally, although it can be so close that you wouldn’t even notice. This will take high resolution to the next level.
Finding and Streaming Hi-Res Music:
When you are streaming music, check to see what the bit rate is. The bit rate is the number that shows how many kilobits-per-second (kbps) are being transmitted. Even at an mp3’s highest bit rate of 320kbps, it doesn’t compare to the bit rate of a CD which would be around 1411kbps. You can see the difference already in how much audio information is being transmitted.
Most streaming platforms like Spotify and Pandora have low bit rates. This will probably change in the near future as high resolution becomes more attainable to stream:
These are the Highest Bit Rates for popular Streaming Platforms:
- Spotify’s highest bit rate ~ 320 kbps (only available to Premium subscribers)
- Pandora’s highest bit rate – 192kbps for Pandora One subscribers
- Tidal’s highest bit rate – 1411 kbps FLAC Lossless (16/44.1 khz). Streams FLAC files at CD Quality
- Qobuz’s highest bit rate – 1411 kbps FLAC Lossless (16/44.1 khz). Streams FLAC files at CD Quality
Is High Resolution Audio Worth it?
Why is high resolution audio the best quality? The use of higher bit depths like 24-bit and above gives recordings a higher dynamic range and a higher signal-to-noise ratio. Higher sampling rates and bit depths make sure the original sound is captured as accurately as possible. With higher resolution audio, you will be listening to every single nuance of the song because all of the detail is still in the file since it has not been compressed to make the file size smaller. A lot of times these hi-res audio files will be straight out of the recording studio and in your speakers or headphones in all of its glory.
The amount of space that a hi-res file takes up is substantially bigger than compressed files, so if you want to invest in high resolution audio you will have to buy compatible hi-res playback devices and sacrifice more storage space. It’s up to you to weigh how much space and money you’re willing to invest to have some hi-res music in your arsenal. You might not need to scrap your entire music collection and replace it with hi-res audio files, but maybe starting with music that you like and want to have the best quality of would be a good start. Sure, the amount of space the high resolution files take up may not be proportional to the amount of added quality you get, but it is pretty cool to think you have the best quality file of your favorite music. Storage space is also becoming more affordable as well, so it may soon be pretty easy to get a hard drive with high resolution music on it at an affordable price.
Remember, the higher bit depths and sample rates help engineers, producers, artists and others involved in the creative process to make quality recordings without any unintended distortions or degradation. Having audio recording that is similar if not the same as the files used in recording studios is pretty awesome to have access to for the die-hard music fans. Maybe at some point it will become overkill to make ultra hi-res audio files and we don’t hear the difference at all, but steering away from compressed files and having uncompressed files with no degradation in signal quality may be a step in the right direction for right now.