Is High-Resolution Audio Finally Going Mainstream?

Tidal high-resolution music streaming

This week the streaming music provider Tidal updated its app for the iPhone/iPad to support their high-resolution ‘Masters’ music streams. The Android app was similarly updated a few weeks ago. So now there is no need to compromise on the quality of the music you listen to for the sake of convenience. Will this be the move that finally kills off the dreaded poor-quality MP3 and allows everyone to make a return to listening to quality music reproduction?

Sound Quality vs Convenience

Suzanne Vega has a lot to answer for, although she didn’t know it at the time. Back in 1987 when computer storage was limited and internet connections (and bulletin boards) were very slow, keeping files as small as possible was paramount. So the mp3 format was devised which ‘threw away’ much of the detail in a music track and then compressed the file in order to significantly reduce the amount of storage space required and time taken to download it. Did it sound OK? Well not really—but the developer of mp3, audio engineer Karl-Heinz Brandenburg, used Suzanne Vega’s a cappella version of her song “Tom’s Diner” to fine tune the algorithm to make it as good as possible. With the rise of the portable mp3 player, add in particular the original iPod, these small files meant you could take your music everywhere. This ultimate convenience meant almost everyone was happy to accept the compromise on sound quality.

What is High-Resolution Audio?

Hi-Res audioIn its simplest terms, hi-res audio usually refers to music files that have a higher sampling frequency and/or bit depth than CD.

Sampling frequency (or sample rate) is the number of times samples of the signal are taken per second during the analogue-to-digital conversion process—for CD quality this is 44.1 kHz, ie the volume level of the audio is measured 44,100 times per second. The more bits there are, the more accurately the signal can be measured in the first instance, so going from the CD standard of 16-bits (65,536 possible volume levels) to 24-bit (16,777,216 possible volume levels) can deliver a noticeable leap in quality. Hi-res audio files usually use a sampling frequency of 96 kHz or 192 kHz at 24-bit; although even higher sampling frequencies such as 352 kHz are available for some music.

Sampling theory states that any frequency can be reproduced as long as you sample at twice the highest frequency (what is known as the Nyquist frequency); so if the human ear can only hear up to around 20 kHz, why do we need higher resolution than CD’s 44.1 kHz? The answer is too technical for this blog, but we’ve provided some useful links for further reading at the end. Suffice to say that the way we hear music is not just about frequency but also about the accuracy of timing; and that filters and other processing required to encode and decode that 20 kHz frequency can introduce ‘artefacts’ that can be heard elsewhere.

Distributing Music in CD Quality and Better Around Your Home

Most multi-room audio systems have been capable of playing CD quality audio in all the rooms throughout your home. However the popular streaming services have, in the main, still been using highly compressed files which have similar quality issues to the mp3. If you wanted CD quality then you had to store the files locally on your network (having ripped them for CDs yourself, our purchased 16-bit/44.1 kHz files to download). Convenience again took over, and as streaming became more popular than having a local music collection; compromises were again made in the quality of music we listened to. Most of the multi-room audio systems that Cyberhomes have installed over last few years are capable of reproducing high-resolution music, just most owners were feeding them with low-quality streaming music.

Tidal Pioneers High-Resolution Streaming

Tidal music streamingStorage space is now much cheaper and internet connections are much faster, so the pressure on filesizes isn’t what it was a couple of decades ago. Tidal were the first streaming service to realise that many people would now be prepared to pay a little more to have all their music streamed at CD quality and introduced their ‘HiFi’ premium streaming service. Further, with the increase in the amount of music that was also available in high-resolution they introduced TIDAL Masters that goes beyond CD quality. This still has to be streamed, so using uncompressed high-resolution files would still be a challenge for some internet connections.

MQA Master Quality AuthenticatedTIDAL partnered with MQA. MQA (Master Quality Authenticated) is a new music format developed by British Hi-Fi manufacturer Meridian. This uses clever techniques for ‘folding’ the extra high-resolution data below the noise floor in a file that is about the same size as a CD quality file. Not only that but the format is also able to compensate for the poor-quality analogue-to-digital (A-to-D) samplers that were used for many early digital music releases. To take full advantage of this high-resolution music at home, your audio distribution system does need to be ‘MQA capable’ but this is increasingly becoming available from many manufacturers. And even if your system isn’t MQA capable you will still benefit from CD quality music.

There is some debate about whether MQA is a ‘lossy’ format. We’re not going to resolve the debate here, but consider this: when an original analogue recording or live performance is sampled to a digital file there are already losses introduced in that file. Even if the digital file is then stored and distributed in a lossless format until it is finally converted back to analogue when you listen to it, there will be losses compared to the original music. MQA aims to be lossless in terms of the analogue domain from original performance to your living room. The only way to judge whether that is successful is with your own ears.

Authenticated Music Files

There is another advantage to MQA—authentication. With other digital music formats, whether it’s mp3, AAC or FLAC, compressed or lossless; you have no way of knowing whether or not the file you are listening to has been tampered with. Many music files have been edited, filtered, dynamic range compressed or had other processing applied; so aren’t a true representation of the artists’ original file. In your own music collection you’ve probably got multiple copies of the same song with different filesizes so at least one of them can’t be the original. MQA has the capability to confirm that the digital file you have downloaded or streamed is the identical file that was issued by the artist or their record company; so you know you are hearing the music exactly as the artist intended.

Upgrade to High-Resolution Now

So whether you have an iPhone or Android phone, if you haven’t already done so, get a TIDAL Masters subscription (a free 30-day trial is available), download the Tidal app and check out your favourite music in high-resolution* (use wired headphones rather than Bluetooth to ensure it stays high-resolution). Then when you are convinced of the benefits, speak to Cyberhomes about getting your home audio upgraded to be high-resolution and MQA capable.

* The iPhone DAC is limited to 48 kHz; so although you will get the benefit of the increased 24-bit dynamic range, you will need to attach an external DAC to the iPhone to also get the full impact of high-resolution. So, if you find your music sounds better using Tidal MASTERS on your iPhone, then know it will sound even better still if your home audio is high-resolution capable with an MQA renderer!!
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on 13 Mar 2019
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