This is the first part of a new series on digital music. Part two is here, stay tuned for more.
There’s an interesting contradiction when we consider trends in listening to music compared to watching video. Video quality has massively improved but audio quality has got appreciably worse.
With video, just think about the enormous improvements in picture (and sound) quality that have occurred over the last few decades. We’ve gone from black and white television screens that were as much circular as rectangular to enormous wall sized wide-screen color behemoths, and what was formerly thought to be wonderful quality video at 220 line resolution (ie VHS) has gone to laser (330 line), DVD (480 line) and on to Blu-ray and HDTV (1080 line) and now up to 4K resolution (2160 line) with hints of continued improvement in the future (anyone for 8K?).
Video has improved almost 100 fold in quality, and has done this not only via recorded physical media (ie Blu-ray disc) but also via internet streaming as well.
But what about audio? The original audio recording technologies (primitive wax cylinders) evolved into 78 rpm records which in turn started to be supplanted by 33 1/3 rpm (so-called ‘long play’ or LP) records in 1948. Stereo sound appeared ten years later, and a series of incremental improvements in both recording and playback technology followed over the next couple of decades.
The Rise of Digital Audio – the CD
An apparently enormous enhancement occurred in the early 1980s with the release of compact discs.
They had several major and obvious advantages over LP records. They had a much greater dynamic range between the quietest and loudest passages recorded, they had much better stereo separation, and they could hold almost 2.5 times as much music on one side, while being much smaller in size. Best of all, they lasted almost for ever, and seldom/never suffering from the annoying scratches and wear/distortion that unavoidably developed on LP records.
CDs store sound in digital rather than analog format, with a sampling rate of 44.1 kHz and a sample size of 16 bits.
These obvious advantages more than outweighed any detailed consideration of the ‘best case’ sound quality of the analog LP compared to the digital CD – while the man in the street could understand ‘plays 75 minutes without stopping’ and ‘almost impossible to scratch or wear out’, who could really understand the implications of sample rate and depth?
(Note this ultra-brief history ignores tape and various other formats that never became universal – in general, consumer tape devices were never as good as LP and CD products, and as for all the other failed products – 8 track cartridges, Minidiscs, and so on, because who really cares.)
Was the CD an Improvement over LP Quality?
In years subsequently, some people have suggested that the CD sound quality is actually not much better and maybe even slightly inferior to LP sound quality – here’s a 2013 article, for example, that makes this suggestion.
We find such commentary unpersuasive, and suspect it is similar to people who advocate spending ridiculous amounts of money on ‘ultra quality’ cabling. In particular, the weakness we see is that the people who talk about the better quality of analog rather than digital sound generally ignore the fact that much of the sound processing between the microphone and the ultimate CD or LP is done digitally. Pure analog audio is very rare these days, making the argument about analog vs digital rather moot.
But we will concede that CDs did not greatly advance the underlying audio quality, and their original specification could well be revised and upgraded to a faster sampling rate and greater sample depth. Unfortunately, although there have been various attempts to introduce new enhanced digital music formats (increasing 16 bits up to 24, and the sample rate from 44.1 kHz to 48 or even 96 kHz), none have gained any market traction or acceptance, and the CD format remains the ‘best’ there is for almost all music.
The Big Backward Step – MP3
Now for the interesting part. After the leap forward presented by the CD, which first appeared in the very early 1980s – almost 35 years ago, back when standard VHS was battling it out with Betamax for video format supremacy – what has happened since then? Video quality has improved something like 100-fold, and indeed, the audio portion of a movie has gone from poor quality mono to now sometimes dazzling quality eight channel (ie 7.1) surround sound.
For audio, the next ‘big thing’ in audio formats was the advent of the MP3 format and the new portable music players – a field quickly taken over and dominated by the iPod. But, whereas a CD has a data bit rate of 1.4 Mbits/sec, MP3 music typically has a data bit rate in the order of 64kb – 256kb/sec.
Now, be careful in comparing these numbers. MP3 format music is compressed, so in theory there is ‘more music information/quality’ per unit of data in an MP3 than in a CD. But, the other side of that coin is that MP3 format music is what is called a ‘lossy’ compression format. It ‘cheats’ and takes some shortcuts in compressing and then re-expanding the music it stores, a bit like a jpg image, which also uses a lossy rather than lossless compression technique. It is hard to describe differences in sound quality without sounding pretentious like a snobby wine reviewer, and so a picture analogy is helpful.
As you can see with the jpg examples above, the difference in quality is subtle rather than substantial, but if you know what to listen for and hear, you will start to notice the results of lossy audio compression. In particular, you’ll perceive a loss of quality in louder passages, and a fuzzy lack of sharpness in quiet passages.
You’ll see a loss of sharpness and fine detail in the picture texture in the more compressed picture above, and the same is true with lossy audio compression. For example, with uncompressed audio, you can hear the sound of the bow being drawn across a string on a violin, and can sense the slight raspiness of it, but when played in MP3 format, it sounds smoother. You can hear the whisper/breath of a woodwind instrument as well as the tone of the notes the player produces, but in MP3, you just hear the sound and not the underlying additional detail.
In percussion music – for example, a piano (which is one of the hardest instruments to record/playback) – you can hear the ‘attack’ of the hammers hitting the strings as well as the sounds they create. And in loud crescendos, if you turn the volume down when playing it back, you can clearly hear the different instruments in the ensemble all contributing to the totality of the sound, whereas if you turn the volume down on a loud bit of an MP3, you realize there’s just a mush/mess of almost static with some detail on the top but nothing underneath.
Some of these issues may not matter so much with some forms of music – in some types of more modern music, distortion is deliberately introduced for effect anyway, and people don’t seek to listen to it for an exact replication of a live performance but rather simply want to have a general background experience to distract them. If you’re listening to music in a noisy environment, or through low quality equipment, then the quality loss is again insignificant.
But for an audio purist who seeks to enjoy not just the musical piece itself but the sound quality of its performance too, MP3 compressed music is a backward step.
To use a possibly unfair analogy, some people drink whisky as a social experience and perhaps to get drunk. Other people sip single malts so as to savor the taste sensation. If your approach to music is akin to savoring your single malts, you’ll be disappointed by MP3 format music.
Whether it matters to you or not, the ‘evolution’ of music storage from CD to MP3 format saw sound quality decline rather than improve.
Digital Downloads Displace CDs
CDs are no longer the dominant way of storing and distributing music. Unfortunately, the successor to CDs is massively inferior rather than an improvement – which is probably the first and only time that a new technology, displacing an older technology, has been worse rather than better.
Digital downloads, and more recently, digital streaming of music, arguably offers you convenience, and possibly offers you some value benefits too, but in return for these benefits, you are required to sacrifice quality.
A No-Longer Necessary – But Still Common – Compromise
It is true there were arguably valid reasons for the quality compromises inherent when the MP3 format first started to become popular (the first iPod was released in 2001). Back then, internet speeds were much slower, and hard disk capacity much smaller (and more expensive) than it is today.
But in the intervening almost 15 years since MP3 technology first came out, what has happened? Typical internet speeds are at least twenty times faster, and data storage prices are at least twenty times lower.
But sampling rates have only slightly increased, usually by less than double. It is now common to find sampling rates of 128kb – 256kb, but even at the maximum sample rate the format can handle (320 kb/sec, a bit less than one-quarter the sample rate of a CD) the sound quality is still poorer than on an old-fashioned CD or an even older fashioned LP.
Of course, it has always been possible to simply copy the digital data on a CD onto your computer, or possibly onto a portable music player, and then play that directly, with no loss of quality. But that sees each hour of music consuming about 630 MB of space, which limits the amount of music you can have. That would mean a 16GB iPod could store about 25 hours of ‘pure CD’ music, compared to almost 140 hours of MP3 at a 256kb sample rate. Most people felt (and still feel) the trade-off in music quality was acceptable in return for the much greater song storage capacity per GB of capacity.
Strangely, music streaming services have also stayed with low bit-rate streaming. Indeed, if you look at ‘internet radio’ stations, you’ll see some offering streaming rates as low as 64 kb/sec, and it is very rare to find any over 128 kb. Yes, if you go to Netflix and watch a high quality video, you might have the data streaming at 5 Mbit/sec, but if you go to an internet music service, your audio stream will be maybe only 128 kb/sec – and probably less than the sound portion of the Netflix movie stream!
Music and its quality has become the overlooked orphan of the digital era. One can only guess as to why this is, but no-one can dispute the reality of the situation.
But now, after all of this, it is time for some good news.
A New Way to Enjoy High Quality Portable Digital Music
We are not limited only to MP3 type music storage. Indeed, we never have been, but the arguments formerly favoring MP3 are no longer as relevant as they were ten and twenty years ago. There are better ways to store music that give a better compromise between storage space requirements and sound quality. Particularly now that storage is much less limiting – either in terms of capacity or cost – there is less need to compromise in quality.
There are a number of music formats that store CD quality music in a compressed format, but without any quality loss when the music is compressed and then expanded back to its original form. Perhaps the best of these formats is called FLAC, and it can reduce the size of a CD by about 50%, with no loss of sound quality at all. This is the best possible way to store and play back your music.
If you are an audiophile, then your best approach to storing music these days is probably to buy CDs, which most of the time remain the highest quality source material we can obtain, then to convert (ie ‘rip’) them to FLAC format, copy them to an appropriate portable music player (Apple’s iPods do not support FLAC format, although most Android devices do), and play back through high quality headphones (not the disgusting little ‘ear bud’ things that one sees everywhere) or a decent hi-fi sound system.
There’s a certain irony in that we’ve ended up with something remarkably equivalent to the technology obsoleted by MP3 players. Remember ‘Walkman’ type portable CD players? This new technology ends up with a similar net audio result, albeit in much more compact space – you can have hundreds of CDs stored on micro-SD cards the size of thumbnails, rather than the old-fashioned ‘wallets’ bulkily containing mere dozens of CDs.
This is the first part of a new updated series on digital music. Part two talks about digital music quality parameters.
We”ll be adding a follow-up article that gives you the specifics of the best software to use to rip CDs to FLAC format and how to do so, and the best portable music players to then store/play your music with.