Digital audio. It’s too computer-y.
I blame USB.
(How’s that for an opening salvo?)
Permit me to explain further.
Let us consider the digital audio newcomer. Let’s call him Bill. Bill has an extensive CD collection and a trusty CD player that has served him well for the past 10 years. He isn’t going to switch over to a new method of playing music immediately. Bill’s not gonna sell his CD player, buy an iMac and rip 2000 CDs overnight. The transition needs to happen slowly. Firstly, he’ll probably want to buy a DAC to augment his existing CD player, but all he hears is chatter about USB DACs. A new language dominates the conversation: adaptive, asynchronous……huh?
There ain’t no USB port on the back of his CD deck and – like me – Bill doesn’t necessarily want a computer in his hifi rig. He doesn’t want to fire up Highway 61 Revisited with the click of a mouse. It feels wrong to him – a sentiment to which many would empathise. If you want people to convert, you need to give them flexibility, hold their hand and take them with you – a way out is as important as a way in. Bill needs a DAC with S/PDIF inputs USB-only DACs need not apply.
Down the track, Bill might then consider an all-in-one lounge room device such as those made my Linn, Soolos, Olive et al. These products might have their own unique quirks and limitations but they fill a reasonable-sized market hole – they bring digital audio to the lounge room WITHOUT dragging Bill Gates or Steve Jobs along for the ride.
An alternative step for Bill might be moving from a CD player to a streaming device. It too keeps the computer-as-transport at bay. Sonos or Squeezebox lead the field in showing us that digital audio doesn’t have to mean computers (in the traditional sense of keyboard, mouse and screen) residing in the lounge room. In fact, at under AU$300, the Squeezebox Touch could be the biggest bargain in digital audio…of 2011, no question. The onboard DAC is far better than many sub-$500 standalone units. You get a touchscreen-controlled device that streams music from your existing computer (which can remain in your study, bedroom, garage) and/or the internet. Squeezebox server is configured to stream thousands of internet radio stations, which for many newcomers opens up a whole new galaxy of music. If the Squeezebox Touch dealt only in internet radio stations, it’d still be worth the entry fee.
From a digital audio point of view, two things stand out when using a Squeezebox Touch:
Firstly, you don’t need to understand ‘how computers work’ to use it. Much like Apple’s iPad, you’re getting the benefits of computer technology without feeling like you’re using a computer. The touch screen interface is so intuitive that many folk won’t know (or care) that they’re using a custom Linux build.
Secondly, your computer doesn’t have to reside in your hifi rack. It can sit upstairs in the study. Or in the garage. The computer’s proximity to the amplifier is irrelevant. It simply needs be connected to the network.
The question then presents itself: which DAC? The Touch has both coaxial and optical outputs, so – as per a CD player – a DAC with the corresponding inputs is all that’s required (which the our newcomer Bill already owns). More observant folk (read: pedants) will note the possibility of pushing audio ones and zeroes out of the USB port. True – but it only works (well) for adaptive-flavoured USB DACs. Asynchronous boxes have issues with signal lock and introduce sonic (digital) artefacts. Boo. Got Squeezebox? Got Sonos? Once again, you’ve no need to concern yourself with a USB-only DAC.
But still manufacturers sweat it. They add 16/44 (Redbook) USB inputs to their multiple-input DACs and then worry that the consumer will baulk at purchasing their product because of such a “limitation”; it’s really not the dirty secret manufacturers think it is. Anedio are currently in the throes of upgrading the USB input on their excellent D1 DAC so that it handles 24/96. Peachtree’s refresh of its flagship Nova – now iNova – has done the same. Why the fuss? USB connectivity should be seen as little more than a convenience. It’s a supporting act to a headline band. That headliner band (for now) is S/PDIF. All this before the dearth of hires music is even mentioned. I’ve said it before and I’ll say it again: a 24/96 or 24/192 version of the same recording does sound better than its Redbook equivalent but supply comes up way too short. Much like USB DACs themselves, Hi-res evangelists are the Joe Pesci of digital audiophile world – all mouth, no trousers. Redbook still rules the roost and will continue to do so for some years to come.
So what of USB-only DACs? Frankly – what about ‘em? Controversially for some, I nearly always advise people to steer clear. “Only buy a USB-only DAC if it offers a sound that’s not available from any other box,” is what I say. Eric Hider’s db Audio Labs springs to mind. His DACs’ sound is unique. There’s a beguiling liquidity to the the sound of the Tranquility SE that I’ve not heard in any of my favoured sub $2k decoding boxes: Lite DAC-83, Audio-gd Reference 7.1 and Anedio D1. Hider’s unit is the only USB-chained DAC that has caused me a moment’s repose……to re-consider the MacBook or MacMini as full-time digital transport. Hider has done what few others have done: nailed Redbook reproduction. Using a keyboard and mouse to control my music night not be ideal, but the Tranquility’s sound quality pros might outweigh the computer-in-lounge-room cons. Y’see: pragmatism matters.
A second high(er)-end candidate for USB DAC pragmatism might be Ayre’s QB-9. I’ve not heard one, but like db Audio Labs, Ayre exclude all but USB because that’s what sound best (to them). Adding S/PDIF focussed circuitry (probably) erodes sound quality.
Exceptions proveth the rule? Nah, saying so would be trite.
At first glance, desktop audio consumers might baulk at the “NO USB DACs BEYOND THIS POINT” signage. Desktop audio is where diminutive form factor overrides the need for ‘best’ sound quality. HRT make good-sounding, cute-looking products for office workers, students and bedroom listeners – people who listen whilst they use a computer to browse the internet, check email etc. HRT’s DACs are USB-only…but, seriously: how small is your desk? Buy a DAC with an array of rear-facing connectivity (so that you can enjoy it in your main rig)…and buy a bigger desk. Or tidy it. Find a way to keep the S/PDIF door wedged open.
Let us now consider the experienced digital audiophile. Let’s call him Nigel. Nigel is serious about the way USB data is transferred from computer to DAC. He likely won’t care for the DAC’s USB port. Why not? The expanding array of USB converter products points directly to the answer. Nigel already owns a USB converter.
Want specifics? The Audiophilleo 2 is a black box that sits between computer and DAC. It (asynchronously) extracts digital audio via the USB port of the computer (using its own clock timing and NOT the computer’s). It then re-clocks and converts the USB input a S/PDIF signal (which is sent onto the DAC). Nerds note: a USB converter that runs a separate clock for each of the 44.1kHz and 48kHz sampling rate families and handles data asynchronously is generally preferred. The M2Tech Hiface is another such product.
Once S/PDIF has run its course, new product revisions will be no doubt be coupled to DACs via protocol up-and-comer: I2S (which separates data and clock information). Few DACs currently support I2S (Lite DAC-83 and North Star Designs are two) – but whatever the outbound protocol of the USB conversion device – here comes the kicker – a computer connected to a DAC via an M2Tech Hiface or Audiophilleo will most likely sound better than a computer directly connected to the same DAC’s USB port.
Until such conversion technology is built directly into DACs (and is invisible to the user), the market for USB transports will continue to flourish. In the land down under, Lenehan Audio have begun housing a John Kenny-modded Hiface inside their flagship PDX DAC. That’s some serious sounding gear right there. Moreover, John Kenny himself has recently announced details of his new DAC that has his battery-modded Hiface baked right into the design. This is where USB implementations are headed…
…and until this design practice goes global (mainstream), neither the digital audio newcomer nor the experienced digital audiophile have serious reason to give their DAC’s USB input more than a second look. Consumers should not worry about USB inputs remaining adaptive and restricted to 16/44…and neither should manufacturers! Even if you’re going the full nine yards – from CD player to lounge room computer – you’ll need S/PDIF inputs on your DAC. With a PC or Mac as your main transport, you’ll have little need for your DAC’s USB port because you’ll ultimately be looking at USB converters to juice the very best from your DAC.
For many, USB(-only) DACs are a one-way street. They offer a way into the world of digital audio, but once in, you’re on a narrow road headed toward a dead end…and you’re using a computer. And using a computer in the lounge room is akin to wearing ill-fitting trousers. They look like trousers, they walk like trousers…but they feel uncomfortable.
I’m not saying USB DACs are irrelevant. I’m saying that they’re a niche (USB) within a niche (DACs) within a niche (digital audio). Therefore, they have to work harder for consumer dollars. My over-arching message here is two-fold and simple to summarise: Prioritise Redbook quality. All other things being equal – prioritise S/PDIF connectivity…until John Kenny and Eric Hider ignite that match of conversation.John Darko runs Digital Audio Review. He lives in Sydney, Australia.