Bits, batteries and BS

A reader writes:

I am a hi-fi person. The kind who likes music to sound as good as possible. I know you are interested in sound too.

Small audio server

I am building the item shown here, which is a Micro ITX system to provide very clean USB signal to a DAC.

It's built around an Intel DN2800MT Marshalltown Mini-ITX motherboard which accepts anything from 8 to 19V DC.

Audiophile battery. Yep, they're serious.

They recommend a battery power source as that clean power helps give better sound. Whether or not you believe in that is another thing. The battery source they suggest is the Red Wine Audio Black Lightning High-Current Battery Power Supply which is $900, costing as much as the entire rest of the system.

I have a problem paying $900 for a battery and charger.

Here's my question. Do you think a standard laptop battery extender (lithium battery plus charger) or similar would work as well? They are a lot cheaper. See for example:

AnkerĀ® Astro3 10000mAh Multi-voltage 5V / 9V / 12V 2A External Battery Pack, $US59.99, or HyperJuice 2 External Battery for MacBook/iPad/USB (100Wh), $US299.95. Red Wine Audio specify the battery they use to be "One 12.8V, 10Ah LiFePO4 battery pack". I can get one here with charger for $US159.99. Does that look like a viable solution to you?

I am not an expert in your area so I can't tell whether these provide clean DC power. For example do they use a components that add noise or is it clean DC? I've done a lot of searching and cannot find the answer.

All the best,


Right off the top: Yes, any other battery with an appropriate voltage and current capacity will work as well as the super-special audiophile one.

Many modern batteries have some circuitry on board to, for instance, cut the battery off before it runs dead flat, or protect against short-circuits. But in normal use, they all deliver DC electricity that's clean as a whistle.


Anybody who seriously claims that running hi-fi gear from a battery instead of wall power will give you...

* Improved dynamics
* Blacker backgrounds
* More natural sounding highs
* Better defined bass
* A larger soundstage
* More holographic imaging

...does not deserve your money, for that battery or for any of their other products.

I would go so far as to say that they do not even deserve the money of Donald Trump, Kim Jong-un, or a professional puppy-drowner.

The Computer Audiophile site is not as badly contaminated with fluffy anti-reason as the real champions of audiophile insanity. But that's only because those champions are so demented that they speak favourably about the audible advantages of $350 wooden volume knobs, small objects made of exotic materials that you're supposed to place in mystically significant locations on and around your hi-fi equipment, $6500 power cords justified via avant-garde atomic physics, and of course plenty of quantum flapdoodle. (That quantum flapdoodle is sometimes quite hotly defended, too!)

The Computer Audiophile forums could be better, too. This wizard manages to list several ways in which uncontrolled observations cause us to see and hear things that aren't there... and then turns around and say that that's why blind tests are useless!

'Cos the reason why people think audio voodoo works, and then don't think it does on the rare occasions when someone takes the trouble to do a blinded test, is because audio placebos don't stop working just because you've discovered that they don't do anything real. And because blinded tests encourage you to give up those placebos that you previously thought made stuff sound better, you'll then be listening to music through less ridiculously expensive gear that doesn't have those wonderful placebos, and this will make you unhappy.

Or something.

Here's another parade of forum-post explanations for why blinded tests tend not to say what audiophiles want them to.

OK, it's not The Computer Audiophile's fault if people say nutty things on the forums.

But the Audiophile himself chimes in further down that first thread, and doesn't really disagree. And he also posted in this thread, to say that in his experience audio bits read from a solid-state drive sound better than the same bits read from a spinning drive.

(See also, the magnificently deranged concept that there is such a thing as an audiophile SATA cable.)

And here a Computer Audiophile blogger explains that the stress of a blinded test "makes it harder to remain objective".

I now choose my words carefully when I say:

For fuck's sake, people.

As I've written before, these attitudes on my part are not just knee-jerk "scientism" that assumes that empirical testing always beats personal experience. A hard-core attitude like this is foolish, when you're talking about unquantifiable things like "how good that painting is" or "how good that music sounds".

My opinion, rather, arises from the large number of tests done in the course of, for instance, developing lossy compression algorithms, investigating the neurology of hearing, and actually testing weird audiophile claims.

Over and over and over it has been shown that the ear is, if anything, even easier to fool than the eye, and that those who claim a special ability to detect differences in stimuli better than mere modern instrumentation and the scientific method can identify, are mistaken.

And it doesn't matter much what those stimuli are. Dowsers, wine experts, "intuitive healers", audiophiles; they're obviously very different in their scope of activity and the likelihood that their activities will cause misery and disaster, but presuming they're sincere, they're all making analogous mistakes for analogous reasons.

This is not a case of different "schools of thought". This is rationality versus irrationality.

Getting back to audio gear that's alleged to sound better when running from a battery than when running from the mains: The makers of this gear may somehow have managed to screw up their power-supply design so badly that the thing really does run better from battery. But that is the only reason why I am not comfortable in betting my life that they are completely wrong.

In this respect, the choice of battery or mains power is rather like the choice between valve or transistor hi-fi amplifiers. A properly-designed transistor amp should be, and as many blinded tests have demonstrated definitely is, audibly indistinguishable from a properly-designed valve amp.

Valve amps sound better when overdriven into distortion, which is why the "valve sound" is such a big deal for guitar, and other musical-instrument, amplifiers.

But a hi-fi amp should not ever be driven that hard.

Show some golden-eared types a badly-designed valve amp that really does sound different from a transistor one (though not necessarily very different from a badly-designed transistor amp...), however, and at least some of them are sure to want to throw money at you.

This sort of thing happens over and over in the audiophile world. Never mind the pure frauds like expensive audiophile cables that turn out to be made from garden hoses and hot glue. Look, for instance, at this highly-regarded little amplifier, which is actually very badly designed, and atrocious in every way.

I suppose some of this stuff may come from people's memories of early versions of new technologies, which often genuinely were inferior to the highly-developed versions of older technologies available at the same time. Early transistor amplifiers could sound quite audibly lousy, for instance, because early transistors were quantifiably unable to amplify audio as cleanly and linearly as vacuum tubes. See also early audio CDs, many of which sounded if not unarguably worse than top-quality vinyl or reel-to-reel tape, then certainly not as good as you'd expect from the slogan of "perfect sound, forever" and the alarming price of a CD player in 1983.

The lousy sound of transistor amps in 1958 and CDs in 1983, though, have nothing to do with how they sound today.

Let me make perfectly clear, however, that I've got no problem at all with the notion that sound quality can be compromised on the digital side of your DAC - particularly when you're using a general-purpose computer as your audio source. There are plenty of possible software and hardware issues that can cause clearly audible problems with the sound.

To give only one example: If you're running an operating system like Windows that has multiple sound sources, not all of them may even show up in the "mixer" control panel. So even if you mute everything but the source you want and set every relevant volume control to maximum (as the Computer Audiophile FAQ sensibly suggests), there may still be obvious scratchy interference noises from sources that for whatever reason refuse to mute, and for whatever reason are very noisy. Like, say, a microphone input with no mic plugged into it.

And then there's the analogue side of the audio chain, which for the vast majority of PCs and Macs today is the audio hardware built into the motherboard. That hardware is almost certainly going to be built down to a price and thus, in the very cheapest versions, may have gross distortion on the level of this stair-step alias-tastic output:

Behold: Aliasing!
(Picture courtesy of Practical Devices.)

Onboard audio hardware is also often not very well shielded from the numerous high-frequency RF sources with which it shares the inside of the PC.

But if you're using a quality internal sound card or any sort of half-decent outboard USB DAC, and if there's nothing on the software side on the PC polluting the bits the DAC, then the notion that the signal coming out will be in any way detectable in a blinded test different between different computers, let alone between one computer running from the mains and an identical one running from a battery, is demented.

Yes, it is possible for an audio system to sound better from battery power than from mains, but only if it's got a badly-designed power supply. If "dirty power from a computer motherboard can result in very audible noise and decreased sound quality", so you need to run even your add-on USB card from battery, never mind the DAC, then there is something severely wrong with that USB card, to the degree that it just won't work properly. Anything that can corrupt digital audio data - remember, this is before the signal even gets to the DAC - in an audible way will also corrupt every other kind of data, and this effect will be noticeable in things as simple as sustained data transfer rates.

And then the Computer Audiophile dude goes and uses a "PCIe riser cable" so he can cram a USB controller card into his tiny computer case - but such a cable is completely unshielded!!1!one! You're running the card from battery power but transferring all of the data to and from it through an antenna?!

UPDATE: Damn, a perfectly good snark ruined - Chris pointed out to me almost immediately that the Computer Audiophile picked a riser cable that already does have shielding!

(I'm sure that if he ever thinks of this, he'll immediately hear the difference and wrap the riser cable with earthed foil, or something.)

Sometimes you strike something that's beloved by audiophiles, inexpensive and functional, like the Tripath "class T" amplifiers (which are their trademarked version of a Class D amp). Built amps of this type, and modules from which you can build your own, are all over eBay and other online vendors. The specs of the cheapest ones aren't very good, but just stick a valve up though the casing, decorate your description of the hardware with some real scientific terms that don't actually apply, keep a wall of pseudo-postmodernist babble in reserve in case of hard questions, and the audiophile market will be fine with it.

Usually, though, audiophile snake oil is expensive, and all you get for your money is a placebo.

This woolly-headedness is for some reason acceptable for audiophile hardware, but not for other technology.

"Well, this is where the GPS says I am, but I think the satellites it's looking at right now lack a certain positional air and musicality. Look, you can see the fix jittering. Well, I can, at least; perhaps your eyes aren't as good. I'll wait until it gets dark so I can try some other satellites when the intervening molecules are cooler."

"I'm pretty sure I play Counter-Strike better when my chair's facing east."

"Water boiled from English 230-volt mains power makes better tea than water boiled from US 120-volt. Everyone agrees 120-volt at 50Hz is almost as good, though."

"My calculator's more accurate when I press the keys more firmly."

Most people would consider statements like these as possible symptoms of a formal thought disorder.

But believing some talisman improves your car's power and mileage, or that a magnetic or copper bracelet helps with your arthritis, or that one should always visit one's astrologer before investing any money, or that water has memory, or that bits and electrons have special properties depending on where they came from?

That's fine, according to a lot of people.

We've gotten past this crap. We no longer believe you can revive a drowned person by blowing tobacco smoke up their arse, we no longer believe the brain's only purpose is cooling the blood, and most of us no longer believe planets whistle around in ludicrous epicycles in order to place humanity at the centre of the universe. And no matter what certain alternative-medicine practitioners say, bleach is not a fucking cure-all.

For pity's sake, we have actually achieved the transmutation of base metals into gold. (Though not the way the ancient alchemists or their rather peculiar modern heirs wanted to do it, which is probably just as well.)

If I were you, I'd forget about taking advice from people who insist, in the face of a world of astonishing technology, that it's reasonable to spend large amounts of money on devices that only make sense if the science and engineering that led to all that amazing technology is actually invalid. I find it particularly galling to see this counterfactual thinking applied to powering of a computer; the people who designed and built the hardware in there, including literally billions of transistors operating at billions of clock ticks per second, have not found any mystic benefit to powering the thing from batteries instead of wall power. But when it comes to the handful of transistors and thousands of cycles per second of a piddling audio output, suddenly some occult force arises that's not amenable to the science that puts supercomputers in your pocket and robot probes on distant planets.

Happily, getting superb audio quality out of a PC is a completely solved problem, thanks to boring old science and engineering. It's not even expensive.

The process is:

1: Buy an Asus Xonar DG or something for, like, fifty bucks. Or less.

2: Install it in whatever PC you like.

3: Plug in your headphones and/or ordinary inexpensive hi-fi amplifier and decent speakers.

...and that's it.

If you absolutely must spend more money than that, I suggest you buy from an engineering-first, low-bullshit manufacturer like Headroom or Practical Devices. Those people usually have a bit of audiophile tinsel on offer, like expensive capacitor-upgrade kits that don't fare well in blinded tests, but they also have plenty of claptrap-free products.

37 Responses to “Bits, batteries and BS”

  1. Bern Says:

    Heh... speaking of ears being easy to fool - the pair of LSK M4s I built some years ago sounded great. Then, when looking at designing some new speakers, I did some measurements using Speaker Workshop & a Wallin jig. Turned out one of the passive crossovers supplied with the M4s was wired together incorrectly. The impedance was peaking at 26 ohms, rather than the 8-ish it should have been, and the phase was similarly affected.
    Do you think I ever noticed any difference between the two?
    Didn't really notice any difference after I re-wired the crossover to the correct circuit, either. Maybe I'm just a cloth-eared git, though. :-D

    • dan Says:

      My own cloth-eared-git threshold is set at "cannot discern whether the speakers are out of phase".

      Anything less than that is fine with me!

      Edit: Actually, I'll add "cannot hear obvious horrible aliasing noise in a poorly-encoded digital audio file" to that. Not being able to hear even quite severe aliasing during a hundred-instrument orchestral crescendo or Slayer song is permissible; not being able to hear it when only one instrument is playing is not.

  2. pfriedel Says:

    Also for the "used to be awful, has gotten better" pile: Lossy encoding. Some of my very earliest rips are pretty awful. Even re-ripping at the same bitrate produces significantly better results now. And now that storage is effectively free and everybody rips at twice what used to be the acceptable rate, the old complaints about mp3s are at least moderately outdated.

    • dan Says:

      ...and a modern well-encoded 128kbps MP3 file can, for a lot of music, sound GREAT.

      For critical listening with certain other kinds of music - unaccompanied voice, pure electric-piano tones, sibilant strings - I think it's uncontroversial that anybody can learn to hear the difference.

      But I'm not sure whether that education actually does you any good.

      • Fallingwater Says:

        128kbps mp3, pah. Try 96kbps ogg. My music player (Sansa Clip+), as well as my phone, support Ogg Vorbis, and I transcoded everything I have in it (I actually use VBR, 96 is just the average). It lets me put my entire 5000+ song library on a 16 GB microSD with some space to spare. I can hear the tiniest difference between supercompressed ogg and 320kbps MP3 in total silence, with good circumaural headphones and lots of concentration, but it becomes entirely irrelevant when I'm out and about.

        Technology is awesome.

        • farnz Says:

          The cool thing about VBR from an encoder's point of view is being able to get a low average bitrate by using very few bits for the bits of the track that are simple to encode (rather than wasting bits as a CBR encoder has to do), and lots of bits when the track is complex.

          I've seen this personally, where a VBR MP3 encoder was using a mix of 32 kbit/s and 40 kbit/s frames to encode a speech, and then when the audience all starts talking at once, it jumped to 320 kbit/s frames for a bit, then reduced back to 96 kbit/s frames for the bit where an audience member was asking a question, then back down again for the speaker's reply.

          The result was a file that was as clear as a 320 kbit/s MP3 would be, but averaging around 45 kbit/s.

  3. Max Says:

    'This is not a case of different "schools of thought". This is rationality versus irrationality.' - I do of course agree, but I'm afraid an overwhelming majority of people don't really see any difference between those, effectively considering "whatever I feel like making sense to me" and "whatever you're trying to support with a rational argument" identically valid things.

    For most people (in my experience) pretty much every bit of science and technology supporting our modern lifestyle is effectively magic, not something subjected to reason or something that can be understood - obviously, there are degrees to this, but by and large that's what I see around me with small exceptions. And that works fine as long as different approaches produce clearly observable different outcomes, but it fails spectacularly in areas where results are hard to quantify, where only reason and exact science could provide a satisfactory arbitrage.

    ...which is why by the way this is a wonderful opportunity for anybody recently recovering from any above-mentioned thought disorders to atone for their past deeds by supporting the movie about the Amazing Randi getting funded as we speak over on Kickstarter (hope that's not too much advertisement considering the direct relation to the subject) - the world definitely needs more people like him... :)

    • Fallingwater Says:

      The vast majority of people don't know how to think rationally. They get by with the absolute minimum required for modern life ("being hit by a car is bad because you die"), but a lot of simple logical thought is completely lost on them.

      Honestly, sometimes I wonder how so many people get by every day with all the irrational crap that infests their thoughts. And it amazes me to no end that them and us logical peeps are actually of the same biological race.

  4. Simon Says:

    > ""Water boiled from English 230-volt mains power makes better tea than water boiled from US 120-volt"

    That one's actually true though. I'm serious!

    In the UK, our domestic electric kettles are restricted to 13A fuses in the plug. 13A at 230V = around 3kW.

    In the US, they don't have fuses in plugs but their outlets are limited to 15A. 15A at 120V = around 1.8kW.

    So we get our tea almost twice as fast as they do.

    Now, that won't significantly affect the taste. But when I want a cup of tea, my definition of "better" tea includes tea that I get to drink sooner :)

    • dan Says:

      I specifically thought of that, then thought, nah, no reader's going to complain about that...

    • alan_cam Says:

      I get my cup full of water to the boiling point, via microwave oven.

    • matguy Says:

      I thought I'd mention that my standard cooktop in the US runs at 220v/240v, although I don't know what the amperage is. I also don't know what the various individual heating elements are rated at.

      It is at 60 hz, though. So any harmonic subtleties are still left to the drinker to uncover.

      Oh, and it's not one of those inductive cooktops. While I hear the resulting magnetic fields from the inductive process can be beneficial to some foods, it could be detrimental to others. Although, the standard range may have beneficial magnetic properties as well, being that it's a big 'ol coil, but it probably depends on what kind of pot you're using that might block the magnetism. (I have a glass tea kettle.)

      But, it's not like I'm cooking wine on it to test with.

    • Itsacon Says:

      That means Dutch tea is even better. We have 230V/50Hz as well, but a typical mains breaker in Holland is 16A: 3.7kW!

      By your defininition, our tea is roughly 25% better!

      (Of course, you still need a kettle that will actually draw all that power. I think most kettles top around 3kW, with the average more around 2kW)

  5. Oli Says:

    Largely agree with you on everything here. One point I'd like to contribute is that many power supplies are not as great as they could / should be. Often, simply plugging another device that uses a power supply into the adjacent power socket of your audio source / computer will generate some short pops and crackles on the sound. It will make far less of a difference in most other situations, as these are infrequent and very transient events.

    • dan Says:

      ...unless the pops and crackles are getting into the music gear via some route other than the power cable, in which case running the music system from battery would make no difference.

      And the wires between a battery and the thing it's powering aren't immune to interference, either; nor is the circuitry in the DC-to-DC converters you need to run a multi-voltage PC from a single battery.

    • Tim Says:

      To expand a bit on Dan's response: unless the device has a true on/off switch set to off while you plug it in, there is a bit of arcing as the plug tips approach the socket contacts. Arcing = spark gap radio transmitter = wideband RF interference, which can get coupled into other nearby electronics in a million ways other than the power connection.

      If your computer audio pops but the computer doesn't actually crash or glitch, that's a reasonably good sign that your computer's power supply hierarchy is in fact rejecting the noise. It's much more likely that some portion of the analog audio signal chain is receiving RF interference.

  6. Tim Says:

    The SATA power filter featured in this audiophile HTPC is a great example of how to sell worthless junk to people who don't understand electronics.

    The most critical power filtering in modern digital electronics takes the form of ceramic bypass capacitors the size of large sand particles. These caps must be connected to IC power pins with PCB traces no more than a few millimeters long -- they'd be completely ineffective if located further away from the chip. You can't improve things with a bulk LC filter located far, far away, on the wrong side of a DC-DC converter which converts 5V or 12V from the PSU to about 1V for the IC.

    In other words, ordinary noise is already filtered very effectively by the devices receiving PSU power in a PC. The SATA power filter could only make a positive difference with a total piece of shit PSU, i.e. one which could be described as "broken". But the proper solution to that problem does not involve spending more money than a non-shit PSU costs on grotesquely overpriced power filters.

  7. rhy7s Says:

    I have a firewire audio interface, the Presonus Inspire 1394 , which has a continuous low hiss - probably wouldn't be noticed in most environments (and occasionally a loud hum which would be) if I plug the power supply of my HP 8510w in while listening/recording. Would a better power supply for the Inspire provide some kind of rejection for this? I'm assuming there's some kind of loop being created when both the laptop and the Inspire are plugged in.

    • dan Says:

      If it were a mains-frequency (50Hz/60Hz, depending on where you are) hum and not a hiss, then yes, I'd immediately suspect some sort of ground-loop problem. Since it's a hiss, though, I'd be more inclined to suspect something's not shielded well enough and is picking up RF from a high-frequency transmitter like the umpteen high-clocked things inside a PC. Those all have frequencies far, far above the audible, but super-high frequencies that differ by some audio-frequency amount can create beat interference in the audible range. (This same fact is the best justification hi-fi nuts have for recording and playing back frequencies above the audible.)

      Since it only happens with the laptop's mains supply plugged in, though, it's possible it's directly picking up noise from low-clocked DC-to-DC converters, which are probably inside the laptop or battery; modern laptop power supplies are generally "dumb", delivering only one voltage. If that's the case then you'd have to set up your own shielding to fix it - wrapping the audio doodad in earthed foil (with any luck you've got a bit of exposed earthed metal on the laptop, like a screen hinge or something) might work. Or you could try a longer cable so you can put the audio interface further away; FireWire cable is I think always unshielded twisted pair, so it probably isn't what's picking up the noise, but you can get shielded FireWire cables cheaply too.

  8. kai Says:

    What I want to know, while we're on the subject of audiophile crap, is that if components sound better when they've been broken in (and they always sound better, you never read a review stating that after 100 hours of burn in playing the sound of tibetan monks chanting under the 13th full moon of the year and then the equipment sounds worse than when it came out of the box)... If they sound better when they've been broken in, then why does second-hand hifi equipment drop so much in price - and the more expensive it was to begin with, the more of it's original value it loses when sold on the second-hand market.
    Shouldn't second-hand equipment be so well broken in that it far surpasses the sound of new stuff?

    • Simon Says:

      The only component which could plausibly change after being broken-in is the actual speaker cones. is a good post on this, & summarises some of the actual research.

      Short answer, two different effects have been measured:

      First one: if the diaphragm has drifted away from being 'centred', i.e. the zero-position isn't what it should be (e.g. cos it's been shipped face-down). This can definitely fixed by break-in... in well under a minute. Speakers re-centre themselves pretty quickly once you start playing sound through them. (Original source: - not free, but the forum post above quotes the relevant part).

      Second possible effect: the stiffness of the speaker cone material may change in use (so changing, among other things, the speaker's resonant frequency). Which does happen. But (you knew there was a 'but', right?): "In one experiment, Nousaine used a driver that was said to need 48 hours of break-in. Placing the driver in a 1.5 cubic foot box, he found the system resonance to be 53 Hz before break in. After 48 hours the resonance was 49 Hz. After a few minutes rest, the resonance had gone back to 51 Hz. The following morning it was back to 53 Hz". So the properties of the material do change slightly in use, but not in a permanent way. (Original source: )

      TLDR: there's slivers of truth in it, but break-in effects of the type & extent that audiophiles claim has never been objectively measured.

      As for why second-hand equipment is so much cheaper, it's the same in any market where most of the initial purchase price of a product is for cachet (making the buyer feel good) rather than the market value of the product. C.f. diamonds.

  9. TwoHedWlf Says:

    I think sometimes the placebo effect isn't necessarily a bad thing. If you install something and think the music sounds better after installing it....Surely it's doing its job of increasing your enjoyment of the experience? Whether or not it's actually changed the sound in any verifiable way.

    Just as long as it doesn't cost $10,000 and requires a speaker cone made of virgin hymens or something...

    • dan Says:

      Audio woo-woo is, indeed, perhaps the least harmful kind.

      But people who are serious about music would probably prefer to be able to buy more music rather than spend that money on useless talismans. And audiophile woo may be a minor contributor to the nonsense that pollutes the world, but it's still nonsense, and it's still pollution.

      The guy who sells $3000 holographic tachyon superconductor power cables is not hurting the world nearly as much as a cancer-cure quack, but that doesn't give him a pass, any more than the guy who empties his car ashtray out the window should get a pass because some rivers are so polluted they can catch fire.

  10. Harrkev Says:

    My advice on getting the absolute best sound possible: do what the musicians do. Go to a real music store (the kind that sells guitars, amplifiers, keyboard, DJ gear, and computer recording equipment. Get a decent audio interface in your favorite flavor (USB, firewire, PCI ,etc.) and enjoy. Not a lot of "mumbo jumbo" there -- just solid engineering. If this is the kind of gear that a producer and/or DJ can make a living with, it is probably good enough for almost anybody. As to the interface to choose: it really does not matter much. USB has more latency than any PCI flavor, but this matters to people MAKING music, not so much for people who want to listen.

    • matguy Says:

      In general, yes, but be careful. Remember, the creative ones among us will often put up with interesting quirks to get what they want. One of them is not always perfect fidelity, sometimes quite the opposite (see the bad Tube Amps Dan mentions.) They may be very non-user friendly. And expect very narrow OS support, sometimes only working with a few applications, or one.

      Also, some of those professional cards/adapters may have outputs that are less than useful for some needs. Balanced outputs are great... if the rest of our audio chain has balanced inputs/outputs. Otherwise, you're adapting it by grounding one of the balanced poles; hopefully after a matching transformer, but not always.

      This is not to steer people away, just be careful. M-Audio has been a fairly well known maker of semi-pro to professional audio interfaces, I don't know if they still earn that designation.

      • Harrkev Says:

        You SHOULD be able to plug a balanced out into an unbalanced input without any problems whatsoever. I actually use a Samson balanced mixer at home -- I feed in the inputs from four separate computers and a rack-mounted radio tuner. The output goes to a higher-end Logitech speaker. The mixer is the only balanced thing in my rack, and it all works great. Having it be balanced means no ground loop hum,

        What you say about OS support is true of the higher-end stuff -- some is Mac only. There are a TON of general purpose USB audio interfaces in the $80 to $150 (USD) range that should work with darn near anything.

  11. Synthetase Says:

    I'm rather late to the discussion, however, a decent, low impedence power supply is actually quite straight-forward to build (see for some interesting ideas). In terms of audio, the only situation where I would consider using a battery for its flat-line DC and zero transformer noise would be on very low input signal/high gain applications such as a phono pick-up preamp. Since you're not using LPs the point is moot. Incidentally, the amount of electrical noise coming from most comuter hardware would render operating it from a nice clean battery utterly pointless.

    The thing is (and I'm surprised nobody else mentioned this) is that having the cleanest possible signal path in this case is pointless. You're sending abstracted digitally encoded information to the DAC from this device, so the fidelity of the waveform being sent doesn't actually matter (up to a point) since the decoder is only interested in the pulses, not how clean they are. Any noise (as long as it's within the tolerance of the data transfer hardware) will simply be stripped by the decoder. It's the fidelity of the analog signal coming out of the DAC you should be worried about.

    • Harrkev Says:

      Not quite true. The cleanest possible signal path IS talking about the analog portion. The sound still has to make it from the DAC to the output connector. Plus, the power supply to the DAC can make a BIG difference in the noise. Noisy power in = noisy audio out.

      For a truly clean analog signal path, you would ideally want a high-quality DAC, high-quality analog filters after the DAC, as well as well filtered power and separate power/ground islands for the analog. All of this takes money.

      • Synthetase Says:

        "Not quite true. The cleanest possible signal path IS talking about the analog portion. The sound still has to make it from the DAC to the output connector."

        From the original post:

        "I am building the item shown here, which is a Micro ITX system to provide very clean USB signal to a DAC."

        As far as I understand it, the OP wants to build a PC to send USB data to a DAC and is planning on running said PC from a battery source for clean DC. As I've already pointed out, this is (1) pointless due to the amount of electrical noise inherent to any computer system; and (2) unnecessary because the signal being sent is an abstract representation of the waveform, not the waveform itself, which means its fidelity (at this point) is not actually all that important.

        I guess if you really want to run the DAC from a battery for pure DC, you could - although I don't see the point. As I pointed out, DC power supplies are actually quite easy to build and any DAC worth its salt ought to have DC filtering caps on the board.

  12. comfychair Says:

    I'm about as far from an audiophile as you can get, BUT... (yeah, I know)

    I have an old, cheap Creative SB Live! card that just sounds absolutely fantastic. Now, I know it's nothing special about the card itself, but some weird combination of that card with the equally weird conglomeration of audio gear I have (had) it connected to. Home-built speakers with a horrible mismatch of drivers, scavenged MB Quart crossovers from a 3-way car speaker setup (which aren't even wired correctly; the 6-1/2" woofers are crossed out at only 300hz, and the 1-ohm 3-1/2" Bose ex-car speakers and the poly dome tweeters driven from 300hz-up, and in series, because of the aforementioned 1-ohm driver issue, all rather poorly installed in Baby Advent II bookshelf cabinets). Main speakers driven by a Sony home theater receiver in plain analog 2-channel mode, subwoofers (one 8-ohm 12" in a way-too-small sealed box, and two 6-1/2" Cerwin Vega drivers in a ported box) powered by an old Pioneer receiver. All of it was scavenged from the junk pile, nothing was bought new.

    Admittedly, all that should sound horrible... but, it doesn't. It's actually pretty amazing, especially with live music. And with that old Creative card, even though rationally I'd be the first to agree that all that talk of 'imaging' and 'sound stage' whatnot is a bunch of shit, this combo does (did) things that shouldn't be possible. Specifically, especially with background sounds like in nature documentaries, it somehow plays sounds you'd swear came from anywhere but where the speakers are located. Like, you will pause the video, walk over to the window and look for the dog you heard barking out in the backyard. Except there's no dog, and when you rewind the video and play it again, there's another dog out in the yard. Except there isn't. Yes it's weird, but it's repeatable, and everybody else hears it that way too, and that little bit of inexplicable magic goes away when you switch to a different, admittedly 'better', sound card.

    But I can't use the crappy amazing SB Live! card anymore, as I finally had to ditch winXP and move on to win7, and Creative cards are designed to be obsolete after they're around 6 months old thanks to their 'Hey, just buy another one! - what are you, a Communist or something?' business strategy. Creative could only be more evil as a company if they branched out into the inkjet printer market...

    With the new Xonar-whatever card it's definitely not bad, exactly, except when compared to the old card.

    • Synthetase Says:

      "rationally I'd be the first to agree that all that talk of 'imaging' and 'sound stage' whatnot is a bunch of shit"

      Actually imaging and soundstage are exactly why stereo was invented. Humans have two ears and can use the delay in sound reaching one from the other to determine the relative position of the sound source. If this weren't true, we wouldn't bother with stereo systems and the problems of having double the source stream, amplifiers, power supplies and speakers of a mono system.

      Listen to a good recording on a half-decent system and you should be able to hear the relative positions of the performers in the stereo image. The caveat here is 'good recording'. Since I put my system together a couple of years ago, I've been constantly surprised at the number of albums with terrible recording/mixing. Some are better than others, but a good example off the top of my head is Eric Claption Unplugged.

      • comfychair Says:

        Ah, yes. No, I meant the audiophile 'bullshit bingo'-style buzzwords in general, not specifically those two. I should have picked more ridiculous ones but that would have required thinking about the audiophile world more than my brain can comfortably tolerate. :]

        • Synthetase Says:

          Fair enough :)

          I know what you mean. My favourite is the oft-mentioned super-special magic power cords. Because apparently, the five hundred miles of standard boring aluminium power transmission grid bringing you energised electrons can be ignored using one metre of magical copper that you just paid $400 for.

          • comfychair Says:

            Or how about... don't they make little pylons to elevate your speaker cables up off the floor, like something you'd see on a model train set? Because, logically, wires deliver electrical signals, and if you shuffle your feet on carpet it generates static electricity, therefore = carpets degrade the sound coming out of the speakers. It's called 'science', look it up! HA.

            Which is a lot like thinking you've proved the earth is flat because you went outside and laid a yardstick on your driveway and couldn't detect any curvature.

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