Computer Audio: A Guide For The Perplexed (HiFi-Plus 70)
As with the choice of hardware, the software used to play can be considered a fit and forget, one-time choice, but if you decide to experiment with different software, the files will not be altered by the investigation process. Endless arguments rage over which software is best, but the differences are usually ones of taste and functionality rather than performance.
In every other way, a computer audio source behaves like just about any other source. The analogue output (ideally from a DAC) connects to analogue inputs on your amplifier or preamplifier. The change this computer-side system is having on the industry means sometimes even the DAC is built into the amplifier itself, and we expect this to become more commonplace.
Yes, but why?
The fact that you can do all this with a computer is wonderful, but what relevance does it have to good audio? One of the biggest misconceptions currently in hi-fi today is that computer audio means compromised audio. It's not hard to see why; many people consider computer audio to be synonymous with MP3 and those same people generally consider MP3 to be synonymous with low-quality MP3. While there are a lot of low quality MP3 tracks in circulation, this does not represent the entire story of computer audio; companies like Linn and HDtracks are now delivering music at master tape quality levels. But even with files that are as good as the original master tape available, the question remains; why should I bother?
There are many answers, but two of the most important are convenience and quality. Computer audio systems give you near instantaneous access to your whole music library. This has a fascinating effect on the way you listen to music. Although you still end up listening to complete works at a time, you also tend to investigate your music collection more thoroughly, as everything is to hand. On systems like the Sooloos for example, you can 'swim' through your record collection, picking out tracks connected to one another by drummer, producer, orchestra...you name it.
Then there's the quality issue. Many feel that CD files sound better when freed from being played direct from the CD, because you are not relying on on-the-fly error correction and because you aren't relying on an opto-electronic mechanism prone to vibration issues. But CD is only the start; high quality downloads offer potentially SACD and beyond sound quality in the home. This is something that only a few years ago was the stuff of dreams; music companies selling the Crown Jewels for not much of a premium. Now, it's becoming a reality. Again, expect to see such things blossom over the decade.
So maybe, the answer to the big computer audio question is not 'why?', but 'why not?' Computer audio will be a key theme in hi-fi of the second decade in the 21st century. It begins...now.
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Comments
Nice piece.
Even I understood it.
:)
Steven Stone
Contributor to The Absolute Sound, EnjoytheMusic.com, Vintage Guitar Magazine, and other fine publications
I understood the article and it was a great discussion of the technologies involved, but it was hardly a beginners guide. I was disappointed because I thought this was going to be a step by step how-to on getting the best fidelity from a computer as a music source. How about a detailed guide on the best way to to rip, store and play music from internet sources? I know this is basic knowledge for some, but I am just now considering using sites like lastfm to download music. I want to do this with the greatest fidelity possible from these sites and in any of the playback modes I choose. If this is too basic for most of your readers, where can I go, and what is the best source to learn these methods?
This is merely the first of a series of computer audio features. The purpose of this feature (which, I admit, loses some of its impact online) is to introduce people to the topic. Later features will focus on more specific aspects.
There is still a lot of hesitancy surrounding computer audio among audiophiles, and many UK audiophiles are something like a year or so behind our American counterparts, in part because we still have HMV Shops selling CDs in every town.
Alan Sircom
Editor, Hi-Fi Plus Magazine
London, England
editor [at] hifiplus [dot] com
Thanks for your reply! I have been a fan of high quality music reproduction for many years, but I am a newbie when trying to use my computer as a music source. I have had friends try to help me but I ended up with mixed results. Also, until I read your article, I never knew that the MP3 format used compression that lost some musical detail. I'm glad I waited before I dove into that technology. I also want to make sure my next vehicle has a quality music system. Some standard six speaker systems sound great, while some hyped 10 and 11 speaker systems are less than stellar. Anyway, thanks for the info and I'll look forward to your next contribution.
Perceptual coding works on the principle that if you play two otherwise identical sounds at different volume levels, the quieter sound is masked by the louder and therefore the quieter sound can be eliminated. This is a very well documented observation. Audible problems surrounding compression systems are based on either the compression system failing to do its job properly or doing its job too well. In reality, that usually means the latter as codecs 'failing to do the job properly' are weeded out long before they make it to the general public.
If a codec (enCOder DECoder) is applied too heavily for the replay system its intended to be used with, the data reduction can be clearly audible and at its worst ends with the 'phasey' sound I described in the feature (for 'phasey'... think of the whooshing guitar sound of Jimi Hendrix playing the opening bars of 'Castles made of Sand' only slightly milder and faster sounding). At its most benign though, data compression can be at least notionally impossible to distinguish from the original sound.
This needs careful listening before deciding to go MP3 though. Many of those who develop the code test it on music that gives it an awfully easy ride - it's worth remembering that the bulk of the original development work on MP3 used "Tom's Diner" by Suzanne Vega, because it's easy to hear imperfections on such a relatively uncomplicated track. Not all music is so straightforward - see what happens when you throw half an hour of Bruckner or an Albert Ayler or Eric Dolphy improvisation at the same compression rate before adopting a compression rate.
Alan Sircom
Editor, Hi-Fi Plus Magazine
London, England
editor [at] hifiplus [dot] com
Alan,
This is a very good article and I enjoyed reading it. This is a very exciting area of our hobby and one that, I believe, can bring in more enthusiasts than any other form of hi-fi playback existing today. I would like to suggest that you add some content regarding how the "bugaboo" of digital, jitter, is being addressed with today's technologies and approaches. Folks, especially those who have had exposure to high quality anologue playback systems, can hopefully appreciate how "pre-echo" and other phenomena of jitter are now being effectively tackled. That, coupled with high bit/sample rate music content and high quality digital playback components provides the contemporary approach to the highest quality music playback available and avoids alot of the "bugaboos" associated with top shelf vinyl playback (high cost, high set-up and maintenance requirements, highly specialized knowledge requirements, etc.) Also, we all know that the availability of digital music content sources are going to increase, while analogue/vinyl music sources are going to remain at the margins - presumably this will help with relative price/selection optimization for digital music content over time.
Again, I thank you for this good, basic article and hope to see more, regularly scheduled hi-def digital music system/content information for those of us that believe that this is the future of our hobby.
Kind regards and happy listening!
Thanks for you feedback. I agree, jitter is something that needs addressing (especially as many think - incorrectly, IMO - the whole topic has gone away, thanks to sample-rate conversion), but I'd say is a feature in its own right.
Alan Sircom
Editor, Hi-Fi Plus Magazine
London, England
editor [at] hifiplus [dot] com
I waited two years for articles such as this. Finally Olive came out with the HD4 and I have a great music server! Thanks.
thanks - this is very helpful. I would like advice on the optimal solution for 1) a multi-room complex consisting of three lodges next door to each other with 15 listening rooms (sitting rooms, bedrooms etc) and 2) three sites in different parts of the world. Ideally for the first situation, one would have one server and for to second situation one would be able copy and synchronise music (and video?) files to the different sites.
There's a useful solution to both called NetStreams. The company specializes in AV over IP. It's not the sort of thing normal humans can (or would want to) do, so it's best to see if there's a custom installer in your region. The audio quality is good, but it integrates well with NaimNet products if you want the sound to move up a gear.
I'd search for the NetStreams site and CEDIA (Custom Electronic Design & Installation Association), for a good nearby installer.
Alan Sircom
Editor, Hi-Fi Plus Magazine
London, England
editor [at] hifiplus [dot] com
@Bob Parish:
Unfortunately, iTunes does that to AIFF files. No idea why... the secret is buried deep within Apple.
The 'easy' solution to this is to convert the files in another program first - Max if you are a Mac user or dB Poweramp if you use PC/Linux (with Wine). You can transcode WAV to AIFF and retain the 24/96 or 24/192 files, then get all the metadata advantages to AIFF.
Hope that helps!
Alan Sircom
Editor, Hi-Fi Plus Magazine
London, England
editor [at] hifiplus [dot] com
@ Malcolm Parks:
Thanks, that's the plan too. Not forgetting the rise of the memory player (I just got a Bladelius Embla – now that's a really fascinating cross between computer audio and traditional hi-fi).
Keep watching the site, as I expect to put up a First Look at the new HRT Streamer Pro USB DAC very soon...
Alan Sircom
Editor, Hi-Fi Plus Magazine
London, England
editor [at] hifiplus [dot] com
Hi Nobby
I'm several weeks behind on this, just doing a browse on some subjects and stumbled upon this topic and alas I'm going to be picky.
CD is not composed of wav files, cd is is composed of 16 binary digit, 44khz CD-DA. (22khz bandwidth)
WAV is an audio waveform at 16 binary digits and 48khz (24khz bandwidth)
It is not possible to extract 16/44 CD-DA, but all grabber software can extract as 16/48 (or variable bitrate/sampling) wav/wave (It's all about not stepping on toes). And though in a technical sense a wave could be termed a form of upsampling - 44khz to 48khz, there is no interpolation of extended data so as long as levelling is not applied then there should be no discernable difference between a 16 bit CD-DA and a 16 bit wav, but they are not the same.
As for Apple being the choice for computer audio, oh sigh. Check out me as "fed up lurker" for my views on that..
I'll stop there, I just wanted to say Hi and wish you well.
As with many applications a, software and hardware associated with computing, it just does not stop! For the novice user it is intact the most daunting and often confusing time =. There is no solution to this as the product range is hug he and some are from different operating platforms. The simplest approach is to develop a trusting relationship with an audio supplier and accept their advice.