If you're one of those people in search of the holy grail of audio fidelity, there's no doubt that using a PC as a complete front-end solution has probably crossed your mind at one time or another. Saving your entire music library to a hard drive and having all your favorite tracks just a few clicks away is certainly appealing, but what about the sound playback quality? Can it compete with dedicated disc transports costing thousands of dollars?

If you haven't made the move to using a PC as your front-end player, perhaps you've been deterred by the fact that PC's lack the dedicated audio engineering that we find in high-end disc spinners. Or, like me, you brought a cheap CD player and modified it to the nines and are now reluctant to invest your time in starting afresh. Such was my case until a couple of months ago when my aging Pioneer PD-S801 gave up the ghost, leaving me scrambling to find a suitable replacement.

I'd invested so much time into the PDS-801; just about every aspect of the machine had been changed somehow. Modifications to the unit included a directly heated triode output stage, fitting a low jitter master clock, replacing all audio critical electrolytic capacitors with ultra low ESR types, and replacing the stock power circuitry with ultra low noise wide bandwidth voltage regulators. Most of the inspiration for these modifications came from cruising DIY audio forums, where other obsessive-compulsive audio crazed folk like me tend to hang out.

Frequenting such places again in my time of need, I noticed that the buzzword in audiophile circles regarding ultimate digital playback now revolves around using PCs to store and playback music rather than the very best standalone transports that money can buy. It seems the buzz is primarily about three things. The first is the prospect of bit perfect data retrieval when using a suitable lossless format to burn your compact discs to a hard drive. The second is using DRC (digital room correction) to help compensate for listening room resonance and reflections. The third, using software based digital crossovers, thus overcoming passive crossover insertion losses and allowing for a more cohesive integration of drive units in multi-driver speakers.

My previous experiments using a PC with mid-budget consumer grade soundcards fell short of providing the resolution, sound staging, and detail retrieval of the modified Pioneer player. I'd put the differences down to the rampant levels of noise present inside of a PC case. After all, when it comes to soul-stirring audio reproduction, ultra low noise clean DC power is a must, and that's not something that we associate with your typical computer PSU. Computer PSUs are primarily designed to supply huge amounts of current on demand, within a certified noise band of course, but nowhere near the quality we find in a dedicated linear power supply. Hence, serious audio playback requires a soundcard designed to deal with the shortcomings of the PC's internal environment.

This leads us back towards pro audio gear used by recording engineers such as the M-Audio and Lynx range of soundcards. Most of the physical differences between pro audio solutions and your basic consumer oriented product can be put down to better components, trace routing, voltage regulation, and power supply decoupling. In addition, the pro cards feature low latency drivers that bypass Microsoft's K-Mixer and can be used with specialized software allowing all sorts of signal rerouting and manipulation. This adds up to making the pro audio offerings flexible enough for people wanting to engage DRC in a fully customized multichannel setup.

Although user reports on some of the internal pro soundcards are very favorable, my interests are stoked by external affairs. An external box presents far more interesting possibilities and flexibility to me when it comes to power supply and output stage modifications. Both are things that I'm too twitchy to leave alone and unchanged until the unit either dies under the knife or gives me what I want in terms of sonics.

One such solution revolves around using the Texas Instruments 270* range of USB - I2S and S/PDIF converter chips, which are used in several commercial outboard DACs that are rumored to be capable of upstaging even the most expensive standalone players. Better still, a range of attractively priced DIY DAC kits based on the Texas Instruments receiver chips are available that utilize levels of engineering found in commercial products costing much more. The unfortunate upshot with the TI 270* family of converters is that they're designed for two-channel use only. Those demanding external multichannel audio units will have to look towards Pro FireWire audio boxes or standalone units like the Behringer DCX2496, which has more functionality than most of us will ever need. If two-channel playback is sufficient then Logitech's Squeezebox music streamer also deserves a mention. Both the DCX2496 and Squeezebox are products that have been thoroughly adulterated by DIY masterminds and there are plenty of commercial or DIY modification packages available for both units that elevate their performance.

We aim to put some of these products to the test in the coming months while also focusing on commercial loudspeakers, disc players, and amplifiers for a range of budgets from pocket friendly to the spare-no-expense league. Today, we will take a brief look at two DIY DAC kits that we've built up and have been subjectively listening to for the past few weeks. We'll also be looking at PC-based DRC in the form of a software package called Audiolense 3.0 using some open baffle single driver speakers from 3D Sonics. If any of this tomfoolery interests you, read on....

The Test System
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  • murray13 - Monday, December 01, 2008 - link

    No one can doubt your enthusiasm Rajinder! I enjoyed reading about what you found out.

    Have you tried using the DRC on a 'good' PC audio card? Now that is something I would like to hear.

    As I personally use headphones, using DRC is problematic at best...

    The one thing that has ALWAYS bugged me about Audiophiles in general is that they use recordings that they were not there to hear when recorded. If you don't know what something is supposed to sound like, how in the world can someone say that one thing or another sounds more 'realistic' than something else, when talking about the n'th degree. {rant mode off}

    With all this said, I look forward to reading the next installment.
    Reply
  • kleshodnic - Monday, December 01, 2008 - link

    Uh, just go digital out (TOS/link or HDMI) to a receiver and let ther receiver do the DAC'ing.

    Want a better DAC? Buy a better receiver. Not only will you get the better DAC, you will get a ton of other great features with a higher end receiver.

    All this talk about computer audio is assuming that you would want to come analog out from the computer. WHY?
    Reply
  • phusg - Tuesday, December 02, 2008 - link

    It would be a lot easier I agree, but AFAIK only really expensive top-end receivers can challenge the analog out you can get from a quality consumer audio card with upgraded opamps, especially when it comes to stereo music. They are also not usually moddable. Can you link to a review of receiver with audiophile quality stereo DAC? Reply
  • pedobosz - Monday, December 01, 2008 - link

    an interesting place to publish such an article. Have you thought of perhaps submitting to Stereophile or The Absolute Sound ? I'm sure you are just trying to raise the awareness of the PC crowd to the possibilities of great audio, but reading through the other replys, I think you are preaching to the deaf......with the exception of the Martin Logan fellow.
    Reply
  • jnmfox - Monday, December 01, 2008 - link

    Computers and audio (mostly Home Theater) are my main two hobbies. I agree this article doesn't fit here at anandtech.com. I've never understood the esoteric audio crowd. If you want quality audio information go to audioholics.com or other reputable audio sites. Reply
  • jabber - Monday, December 01, 2008 - link

    I have to say the article and lengths gone to are way over the top for what in most cases is required.

    The kits combined with the PC audio side is way esoteric too.

    Well intentioned but sledgehammer to crack nut.......
    Reply
  • haukionkannel - Monday, December 01, 2008 - link

    Hmmm... When we talk about HiFi nothing is "bit over".
    For a hifi system this was relative middle range solution. The biggest consern, if you have to find one, is that the speakers will most propably have the biggest effect an the hearing experience. These type of speakers ar not meat to be the most precise in their "room" picture. And I don't say that it's a bad thing! They are good speakers. Some studio monitors would maybe be better for testing the PC as an "Hifi" sound source, because they try not to affect the sound at same way as some High end HiFi speakers, but again it's more of a matter of taste. For example Genelec speakers sound good for Vocal based music. These in here are better in music where accuracy is not so important. So it allso depends on what music you like to listen to. Just like someone above said.

    I would like to see how the sound compares between good Hifi cd-player and a PC. With the same music piece and speakers. This set with those tubes can make the sound varmer, that is good for some not so good mp3 files. More accurate monitor speakers and normal amplifier, will most propably reveal the difference between good cd and not so good PC based mp3 more clearly.

    Most people who are really interested in HiFi systems spent even more money than in test to their system. The real guestion is that is the PC good enough soundsource for system like that.
    Reply
  • jabber - Monday, December 01, 2008 - link

    Yes but real high end hifi is really usually bought by what Top Gear would call 'cocks'. Folks that just see money and how much they spent rather then just enjoying music. $50000 hifi systems geared to playing just 10 specialist audiophile CDs just screams "I've led a sad and lonely life!" to me.

    Show me a $1000 system surrounded by piles of CDs and LPs, now thats an exciting system!

    The readership of this site I would say on the whole would have far more modest hifi setups.

    Once you spend so much on a hi-fi you fall into the trap of listening to the equipment rather then the music itself.
    Reply
  • Spivonious - Monday, December 01, 2008 - link

    Spending that much time and effort to listen to pop music is just about the silliest thing I've ever heard.

    At least put something on that will work the equipment, like a Beethoven string quartet, or a Bach choral work.

    And you never even touched on the issue of vinyl vs digital. To my ears, vinyl sounds so much more organic than the plasticy sound of CDs, even through a $15,000 tube-driven stereo system.
    Reply
  • Rajinder Gill - Monday, December 01, 2008 - link

    Actually, I'm just listening to some Vaughan Williams right now. Just because there's no mention in the article does not mean to say I live without classical pieces.

    Peace...
    Reply

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