Nicholas.Bedworth

The high-end ones tend to cost around $8500. There are of course less expensive ones; perhaps you might list the ones you like.

There are just a few things you need to know, and they're quite easy to understand. The quantization process (converting continuous analogue waveforms into numbers) inherent in digital audio causes various kinds of artifacts that are highly correlated with the signal, which is a significant problem. On average, the number isn't quite right. By adding small amounts of random noise to the process, the resulting quantization artifacts are no longer correlated with the signal, which is a fundamental benefit. The down side is that the overall signal-to-noise ratio is slightly lower than before, but you'll never know in most cases, and you'll definitely appreciate the lack of quantization noise. Thirdly, the resulting overall noise can be "shaped" and essentially parked in parts of the audio spectrum where it is even less likely to be noticed. Astute readers will of course recognize that as far as information or energy is concerned, well, it can't be made to disappear, but at least it can be put somewhere where it causes less problems. The www.whatsbestforum.com contains truly expert discussions from the best minds in this field. Other unnamed publications discuss dithering in the context of the Weiss INT202 and Audiophilleo transports. TPDF and UV22HR are commonly-used algorithms. The main thing to avoid in iTunes is any internal sample rate conversion, volume leveling and the like. This causes dithering and other modifications to the data. By selecting bit-perfect output from iTunes, the resulting bitstream will head towards your DAC intact. In Windows, WMP always dithers the outut, but the algorithms are of high quality. 3rd-party players such as JRMC, when used (Windows 7/Vista) with WASAPI event, will give bit-perfect output. So, if you're using the Weiss DAC 202 or Berkeley Audio Design alpha DAC, for example, feed them a bit-perfect data stream and use their internal attentuators. Weiss divides the output into various ranges using analogue technology, and then applies digital attentuation within that range. The BADA, AFAIK, is entirely digital. Some transports such as the USB Audiophilleo and FireWire Weiss INT 202, have digital attentuation built-in. For the Audiophilleo, you can bypass its attentuator by setting it to Direct (bit-perfect) pass-through mode, and use the attenuator in the DAC, or you can set the DAC to its bypass mode, and use the attenuator in the Audiophilleo. (I forget if the INT 202 has a similar mode, it may...) On systems that are very refined, you'll notice differences between the various attenuation methods, and these qualities may in fact vary with sample rate, just to make things easier. Suffice it to say that the dithering techniques used in any of the products mentioned are advanced and subtle, as they reflect the life-long accumulation of audio engineering and listening experience.

http://www.holmacoustics.com/dspre1_introduction.php This was reviewed in TAS 208, not by me, but it's a relatively new design that has rather versatile connectivity. And it measures the speaker output near-field, then the room, which is a bit different from many such devices. Without doing the room EQ, in almost all cases, you'll only be getting a fraction of what your system can deliver. And the OP mentioned bass gain of 3 to 6 dB sounds about right. Even with a crude EQ in common media players, knocking the bass down several dB will often result in more and better bass

Hey, mail some out here. How many of them did you eat?

Lynching "Nick" makes a big difference to me! Then what will I do? The employment possibilities for lynched audio enthusiasts are sort of limited these days Nobody doubts Clay's enthusiasm and sincerity. He's making a big effort to figure this all out, which is commendable, just as everyone else is. And everyone who lives close to the North Pole deserves every consideration at this time of year. The main point here is that in the technology space, one basically has to forget what one thinks one knows, about every five years, and start over.

Given the amount of work goes into your or my reviews, my only push-back to your admonition is that narcissism couldn't possibly be enough of a motivating influence . Not even for me. This is your forum, you do all the work, you police it and try to make peace, and have to kick off people spouting profanities and all that. You asked me earlier not to have links to my articles on competing forums, no problem, and thus the "over there" reference to the articles he needed. In the future, readers can find them on their own. We all agree that bit-perfect is just the start, but it certainly is a foundation for getting the best possible sound out of the digital bitstream. And there are so many ways for beginners, as well as experts, to get this one wrong that it justifies the emphasis that we all put on it.

Hey, he also wrote something like "I've never been one to advocate sex, drugs and violence, but they always worked for me".

The Mac experts here will have the definitive instructions, but the basic idea is that you're trying to avoid software sample rate conversion, which by definition won't be bit-perfect, or using dithered volume, or "leveling" between tracks. Yes, setting the volume set to 100% should pass everything through intact provided nothing else is interfering. One nuance is that sometimes software updates, etc., will unhelpfully "adjust" some of these settings. If you're using regular and high-resolution audio files at different sampling rates, you may need to double-check to make sure things are as you want. Bit-perfect is a refinement; you'll still get very nice music playing through your speakers without it, but for debugging the rest of the chain, bit-perfect is a good place to start. But I'm sure the Apple enthusiasts here will give you the latest on it. You're doing the right thing, trying a lot of devices, getting conversant with the technology, and learning how it all fits together.

Doesn't matter which OS is involved. Once you have established bit-perfect output, that's it. Note that iTunes can support bit-perfect, or dithered attenuation and sample rate conversion. The latter two do not produce bit-perfect output. Forget the preamp. Get a DAC or interface that has pre-amp functions in it. See my reviews also at 6moons on the Weiss INT 202 and the Audiophilleo (more have discussed frequently here as well), along with the reviews on the Odyssey Kismet amps (talk about high current) and Wilson Sashas. These articles contain a lot of practical information about setting up a computer-driven digital system. Now, one really, reall basic question to ask, and my apologies for asking this, but are you sure you have the speakers connected properly with respect to polarity? If one speaker is reverse polarity from the other, as the Wilson owners manual suggests, the results will be "interesting". Just have someone double-check your work. I not familiar with the speaker cable you were using, but make sure (1) the speakers are not out of phase with respect to each other and (2) that you're not switching + and - to both speakers. This second error reverses absolute polarity, which isn't helpful, but it's not as gross a problem as (1).

One point that doesn't seem to have come up yet is with JRMC, be sure to set the WASAPI (Windows Audio Services API) setting correctly. It's very easy to do. Go to tools/options/audio output/output mode/WASAPI Event Style. You'll find that in this case, the Application and System volume control modes in JRMC are disabled; only the Internal is still functional. Use Application. This disables the software dithered attentuator in JRMC, and guarantees (assuming a lossless audio compression techniqe was used to make your audio files) bit-perfect output from the USB connector which then drives a hiFace, Audiophilleo, WaveLink, etc., or USB DAC. As OP have mentioned, the Maggies need gobs of high-current solid state power. BTW the comments that suggest software attentuation is inferior are not generally correct. It all depends. A skillfully-done software volume control has many sonic advantages, linearity, channel tracking and stability among them. And they don't wear out over time Some computer interfaces (the Weiss INT 202 and Audiophilleo, for example) that feed S/PDIF or AES to the DAC do in fact have very good software attentuators in them. So you want to be sure you're feeding them "original" clean, bit-perfect bits, not ones already dithered. Same thing applies for DACs that have attenuators (and there are several types, ranging from analog to hybrid-analog-digital to all-digital). They need bit-perfect to sound their best. The choice of USB cable will depend on many factors. Some devices can use anything, apparently; others are picky. Don't worry, you'll get there! And the goal will be very pleasing indeed. As you can see, there are several moving pieces here, and getting the bit-perfect data stream under control is important. Now go on to solve the other problems.

You certainly bring up a good point. Brainless iPads play back bits just as well as a large and expensive laptop with an 8 core processor. They just don't do it above 48 kHz at the moment. An iPad may be slow but it's still way faster than what's required for audio. And think in 2 years when the standard-issue iPad or Android tablet has, say, 512 GB or more... and unused storage can be pooled between devices over WiFi (more assuredly not FireWire). Whether these will support high resolution formats remains to be seen, but the storage will be close enough.

Look for digital audio entries... quantization, A/D and D/A conversion, compression, etc. There's a lot of good material there. You've definitely understood the main point, the ones and zeros are conceptual, the rest is electrical. Fourier analysis shows how all the sine and cosine waves add up to form, in this case, a square wave. And these sinuosoidally-shaped, continuous waveforms are adversely affected by trace width, impedance, resistance, sun spots and on and on. So there's nothing magical about digital signalling, and as you get deeper into the topic, this technique introdces all kinds of problems of its own.

is just one of many protocols that they use over fiber. That at least is what I observed over the years at leading-edge studios. Given that we were talking about FireWire already, it was of interest to me to see the historical origins of the fiber plants in the first place and some of the other protocols that survived, even though the hardware behind them didn't.

The issue here is that the notion of a binary digit, or bit, is an abstract mathematical concept. Digital signals are electrical waveforms that just look funnily. They have extremely sharp corners, which are formed by the high frequency components in the waveform spectrum. And you better believe that capacitance alters the shape of the waveforms such that downstream equipment might not interpret them correctly information-wise, or at the right time (the jitter phenomenon mentioned by the OP). In addition, if there's digital media player software involved, the device may not deliver output data which is a bit-perfect copy of the original. Typically media players do volume control dithering, resampling, and otherwise alter the bitstream. You can defeat these in some cases, but it's always something to watch out for.

One doesn't need to make any predictions, just observe the trends that are already well-underway. And in the 25 years of my reviewing high-end audio and video gear, how many transitions have we seen already? They seem to happen overnight, although in reality, it's 2-3 years before there's a major shift in the center of gravity. It usually takes people a while to wake up from their stupors to see that the times have changed, but the awakening tends to be pretty quick. And rude. Most of us have seen the move from vinyl to CD, film to videotape, videotape to DVD, CD to files, wired to wireless, 1 MHz minicomputers computers at $100,000 to 1 GHz desktop computers at $1000 (that's a 100,000:1 price-performance improvement increase in 10 years). And my apotheosis the other day came about when, just for fun, it occurred to me to try controlling a digital media server wirelessly with an Android phone. Firstly, it worked. The GUI was produced by a Web server, the Android browser went to that IP, done. It dawned on me that, except for (temporarily) less total storage, the phone could do everything the $7000 media server did, and in addition, it allowed one to control the music from anywhere in the house. And the iPad USB connector works perfectly with various interfaces (you need a tiny hub in-between in some cases). The only shortcoming is the current limitation to 48 KHz sample rates, which undoubtedly could be raised without much effort. Just look at the chart of how quickly Apple how chopped FireWire out of the iPod/iTouch lineup. In a couple of years, it was all over, and these devices became exclusively wireless (see above) or USB. And make up a little chart for each of the currently-selling Apple Mac computers, and watch what happens next. You can take two off the list today. The obvious question is, how many of the Macs that still have FireWire have anything attached to the port? My guess, informally corroborated by my friends at Apple tech support, is under 10%. That's today. You don't need FireWire for digital audio, or video, or, really, anything anymore. Companies that are successful generally don't keep making things that consumers don't need, because it runs up the bill unnecessarily and provides zero benefit. Faster, cheaper, and higher performance is the name of the game; burning real estate for obsolete interconnect isn't part of the deal for long. As of 1 January 2013, let's see whether digital audio streaming is a common hand-held experience. It is already, at the leading edge. And of course the number of hand-held devices can grow much more rapidly than laptops. If one has an amplifier that is controlled by digital data, one can just stream wirelessly to it, and that's it. There's no DAC, no preamplifier, no interconnect cabling. Just a screen, the files, and the digital amp. DACs are a legacy technology, here today, but probably not needed much tomorrow.