High resolution audio: myths and realities – 2
If we stick to the characteristics of the CD we can see that our music is obtained by taking 44,100 samples per second (correspond to 44.1 kHz) from the original analog signal, and each of them is encoded in a data package that It uses 16 bits. And at this point, finally, it is where high-resolution audio comes into play.
Coding
The starting point of this technology is easy to understand: it presupposes that if we increase the resolution, the sampling frequency, or even both parameters at the same time when passing an analog signal to the digital domain, we can “reconstruct” the original analog signal With more precision. And it really is. For this reason, the specifications commonly used in high resolution audio formats are 24 bits and 96 kHz, or 24 bits and 192 kHz. Both options, on paper, should allow us to recreate the original continuous signal more accurately than the 16 bits and 44.1 kHz of the CD, or, what is the same, will discard less information from the original sound.
But this is not all. In addition, increasing the resolution to 24 bits increases the dynamic range and improves the signal-to-noise ratio (our Xataka Smart Home partners explain what these parameters mean in this post). A resolution of 16 bits allows us to encode a total of 65,536 possible levels for each of our samples, while a 24-bit one reaches 16,777,216 levels.
The resolution commonly used in high definition audio formats is 24 bits, and the sampling frequency 96 kHz or 192 kHz
The difference between the two extremes, which is where the lowest and highest levels are located, indicates the dynamic range difference between one resolution and another. With all this data on the table we can think that high resolution sound should offer us more quality than the audio of a standard CD. And it is so, but, as we will see later, there are factors that limit the experience and that users must take into account, beyond what the industry “sells” us.
Internet: key to the success of HD audio
At this point we can understand without difficulty that the size of a sound file depends on the resolution and sampling frequency used to encode the music it contains. The same issue occupies much more if we digitize it at 24 bits and 96 kHz than if we do it at 16 bits and 44.1 kHz. However, we have a very interesting resource that helps us save space: compression. Currently, high resolution audio is usually distributed in six different formats (some of them offer compression without loss of quality): FLAC (compress without loss), ALAC (the lossless compression technology proposed by Apple), AIFF (it is the format of Mac sound file), WAV (this is the sound file format created by Microsoft and IBM for PCs), DSD DFF (SACD format encoding technology) and DSD DSF (DSD variant for Sony VAIO computers).
Of all the formats that I have just mentioned, the most used to distribute high resolution music on the Internet are FLAC and ALAC because both offer a very interesting compression rate, and without loss of quality. And we all know that size matters on the Internet. And a lot. In fact, the network is playing an essential role in popularizing high resolution sound.
