High-resolution audio, or HRA. It’s a term that’s banded around a lot, even more frequently of late thanks to more and more technology adopting its practice (2015 is the year it hit the mainstream it would seem!) But have you ever wondered… what exactly is high-resolution audio? And, more importantly, why should you care?
Well, quite frankly, if you’re into your audio (and I think it’s fair to assume you are since you’re reading a hi-fi blog) then high resolution is something you should definitely care about. Especially if you have yet to surcome to the digital revolution. High resolution means that digital music can truly hold its own against its analogue forefathers, but more on that later. First, let’s get down to the nitty gritty..
What is it?
On the surface, high resolution is a fairly simple concept. But as with so many relatively ‘new’ concepts in this industry, the definition isn’t particularly clear, nor is it stationary. Hi-res basically refers to…
“High-Resolution Audio refers to a collection of digital processes and formats that allow the encoding and playback of music using higher sampling rates than the standards used in CDs.” ~ Sony
Which basically means there isn’t a single ‘process’ that achieves high-resolution, nor is it a specific format. What we’re trying to say is, when it comes to hi-res, it’s not so much about the journey, it’s about the destination. A destination which is, quite frankly, not within any sort of universal criteria. However it is worth noting that the commonly accepted definition is of a higher sampling frequency and bit depth than CD, which is 16-bit/44.1kHz. High-resolution audio files usually use a sampling frequency of 96kHz or 192kHz at 24-bit, but it’s also not unheard of to have 88.2kHz and 176.4kHz files too
What does all that mean? Well, we’re getting to that.
How Does It Work?
What hi-res boils down to is, the sampling rate. The higher the number of ‘bits’ per sample. Sampling frequency means the number of times samples are taken per second when the analogue sound waves are converted into digital. The more bits there are meanwhile, the more accurately the signal can be measured in the first place, so 16-bit to 24-bit can see a noticeable leap in quality. The aim of sampling something at a higher resolution is to garner a closer replication of the analogue wave than traditional 16 bit sampling (i.e. CD quality).
Digital files have typically suffered with loss due to the compression required for digital files. The rise of the mp3 and its legendary tiny file sizes (great for portable players, not so great for sound quality) meant that lossless digital files became the norm, and despite their convenience, their poor quality earned digital music a bad name in the high-fidelity. But, as the demand for a lossless digital format grew, these formats began to emerge. The closer these formats came to replicating the original analogue wave, the less ‘loss’ in quality and the better sounding the music.
HRA Formats
As you can see from the image above, not all digital audio files are created equal, in quality or in size. There have been dozens of such formats emerging ever since the late 80s, but it
FLAC
Free Lossless Audio Codec is one of the most widely supported of all the HRA formats, and the first to emerge into the likes of portable and other commercial devices. It was specifically designed for being compact, which means despite the improved sound quality, the size of the file is still relatively small.
ALAC/MP4
Apple Lossless Audio Codec developed by Apple (as you may have guessed), and can be recognised from its MP4 container. This is the lossless format supported by iOS devices, which typically will not support other HRA files.
WAV
Waveform Audio File Format is the Windows OS answer to the ALAC. It was developed bny Microsoft to enable the storage of raw, uncompressed audio files on PCs. It is of a much larger file size than most, which hasn’t made it overly suitable for portable devices until recent years. As storage improves, as does the ability to house bigger files!
DSD
The new(ish) kid on the block! Direct-Stream Digital is the trademark name used by Sony and Philips for their system of digitally recreating audible signals for the Super Audio CD (SACD). It boasts a sampling rate of 2.8224 MHz (64 times the CD Audio sampling rate of 44.1 kHz, but only at 1⁄32768 of its 16-bit resolution). It’s pretty sharp, basically.
Why Should You Care?
High-resolution isn’t quite commonplace, but its slowly seeping into commercial use that isn’t exclusive to the high-fidelity community. Certain smart phones and portable devices now carry the abiloty to deliver high-resolution formats. Yes, it isn’t just a question of having and playing the file, you need the gear necessary for it. But once you have it, you will experience something akin to not only CD quality, but SACD quality, which is pretty much the closest thing you can get to analogue in a digital format. So, if you care about your sound quality (and I mean really care) then hi-res is something you need to be aware of. It’s coming.
If you would like to find out a bit more about hi-res, including how to get it yourself, then give us a shout! We are fully educated on the matter, and know exactly what you will need to get high-resolution sound (in all of its wonderfully detailed glory) in your life.