There’s a diagram that does the rounds online that neatly sums up the difference between the quality of equipment used in the studio to produce music, and the quality of the listening equipment used by the consumer.
It shows a vintage Neumann microphone (which you might be able to buy for around A$12,000), plugged into a vintage Neve mixing console, worth hundreds of thousands of dollars. The signal is then recorded onto a well-maintained vintage tape machine, before being transferred into the digital domain using top of the line analogue to digital (AD) converters – and finally mixed in an acoustically-treated environment through accurate, full-range speakers.
After all this time, money, care and attention has been spent on the production, the final playback system is an MP3 file being played through an iPod using A$10 ear-bud headphones.
As someone who records, produces and mixes music for a living, the quality of the playback systems used to listen to my work is a constant source of frustration.
I know I’m not alone here, and in a contracting industry with ever-shrinking budgets, it’s getting harder to justify the investment in good quality studio equipment when the end result is a low-resolution MP3 file that’s going to be played through laptop speakers.
Any attempt to improve the quality of average domestic playback systems seems like a good idea to me, so when Neil Young announced a new competitor to the ubiquitous iPod/iPhone, the PonoMusic player, complete with high-resolution file playback and better quality components, I was curious.
Considering Young’s attendant Kickstarter campaign met its goal after just one day and the standing ovation he scored when he presented his concept at the music and tech festival SXSW last week, there are clearly plenty of interested music lovers keen on an improved format as well.
In audio circles and online production forums, the debate between the pros and cons of analogue vs digital sound never goes away. Neil Young himself has been an outspoken critic of the sound of digital audio over the years and his criticisms of digital audio were also aired in the recent doco Sound City.
Decoding file types
With the announcement of PonoMusic, the debate has widened and now consumers are expected to make informed decisions about the differences between all kinds of files: MP3s, AACs, CD quality 44.1kHz /16 bit and “Ultra high-resolution 192kHz/24bit” FLAC audio. They’re also expected to be acquainted with the benefits of these higher-resolution files.
What do these numbers and letters actually mean?
Mp3s and AACs are data compressed: that means a “lossy” compression codec has been used to reduce the file size – meaning easier downloads and more songs on your iPod. Whenever you purchase music on iTunes (or purchase a license to listen to that music, you don’t actually own the recordings – this belongs in another discussion about why we need alternate models to iTunes), you’re downloading AAC files, not full CD quality.
The trade-off? A reduction in the quality of the sound. How much quality has actually been lost is a matter of great conjecture, though there is general consensus that low bit-rate MP3s (such as 128kbps) are audibly inferior to CD-quality files.
CD audio and the high-definition formats are either uncompressed or use a “lossless” compression code, such as FLAC (Free Lossless Audio Codec). The numbers in 44.1kHz/16bit and 192kHz/24bit relate to the sampling rate (high frequency resolution) and dynamic range (the degree of amplitude variation possible between the loudest and softest passages).
CD quality audio is 44.1kHz/16bit. Sampling rates and bit depths higher than CD-quality, known as high-definition audio, seem to most commonly be either 96kHz/24bit or 192kHz/24bit.
It’s well beyond the scope of this article to delve into how digital audio really works, so instead I would recommend this paper from audio engineer and programmer Christopher Montgomery, or his video on digital audio.
After watching an engineer explaining the digitisation of sound, Neil Young’s underwater analogy, in which he claims that listening to CD quality audio is like listening to sound about 200 feet under water (7 minutes into the PonoMusic introduction video) seems murky at best.
To sum it up, CD-quality audio is fine and the higher resolution files are pretty much pointless.
The weakest link
Turning to higher resolution digital audio is a bit like TV manufacturers advertising new screens that can reproduce colours well above the spectrum that humans can actually see. Unless every part of your listening environment and audio path is completely optimised, there is really no benefit to any higher-definition audio than CD quality – and even then the jury is still out on how defined those benefits really are.
An audio signal chain is only as strong as its weakest link. In a portable music player, once you reach a certain level of fidelity, the weakest link is not the file resolution but the digital to analogue, or DA, converters (the electronic components responsible for turning the digital file back into an analogue audio signal), amplifiers and the speakers or headphones that are being used to listen to the music.
I spend around 40 hours a week with my head stuck between an expensive pair of speakers listening to music being played through expensive DA converters. After I finish mixes, clients frequently check them through the speakers on their smart phones or laptops.
As a mixer I know how important it is for my work to translate across many different systems – but couldn’t we set the bar just a little higher?
Well, PonoMusic is setting the bar a little bit higher, and I think that’s a good thing. Having Neil Young as the voice of PonoMusic brings a certain degree of legitimacy to the project, and from what I know of Young, he’ll be doing this because he really wants to see a big improvement in how we listen to music, not simply a big paycheck.
But we also need to ask how improvements in the conversion and amplification stage will raise the quality of the listening experience – not just the ultra high-res files being used. Research consistently shows that any perceived benefits to higher bit depth/ sample rate recordings are anecdotal and almost impossible to quantify.
Hopefully when the PonoMusic player is released, someone will set up a properly run blind test to tell if people can actually hear the difference between the “ultra high-res” files compared to the plain old “high-res” files. I’d be happy to give it a shot.
I’ll be surprised if anyone can tell the difference between a CD quality file and the PonoMusic ultra high-res file under blind testing – but I won’t be surprised if the device sounds better than its competitors due to the improved components used in the manufacturing and design.
Are you an academic or researcher working in sound production? Contact the Arts + Culture editor.