No, that can't be it - cts reliably uses caps when he writes articles for Kuro5hin. It has something to do with formal and informal modes of thought. It's just now that I realized that his informal mode of thinking might have been filtered through a cloud of halogen gas. Cl is definitely not your friend as far as breathing and subsequent activities go...:-)
First of all, closely coupled (of neccesity, because magnetic field effects fall off as the square of the distance) induced fields of 6 MHz are not in any way real-world interference for your typical home theater setup. Though I'll come back to that.
Secondly, and as the author of the paper notes, the cable impedance is 50 ohms, and so in order to induce a change in the signal carried inside, the power of the 6 MHz signal has to be fairly extreme in order to induce any change within the cable.
Third, again as the author of the paper notes, the interfering signal is a 6 MHz two volt square wave, something you aren't going to see in a home environment even if there was a 6 MHz signal source. Heck, you won't even find that in most labs unless they're trying to make it, as is the case here.
Fourth, none of this in any way implicates the cable as a source of jitter. It implicates outside signals as a source of jitter; the only related question is, does a really fine cable do a better job of keeping real-world noise (IOW, not a 2 volt, closely coupled, high power square wave) out of your home cables? And the answer, as we all know, is no, it does not. It is trivial to make a cable with a nominal 50-ish ohm impedance on a per conductor basis.
Sixth, home theater HDMI uses differential signaling [TDMS]... so induced signals like this are irrelevant anyway, as they are by their nature common mode.)
Seventh, the paper you have there does not test cables. It tests transformers. There is no question that the recovery interface, when actually different, will provide for different types of recovery. Hence his spread of results over his spread of tested transformers.
Eighth, you should note that even in the case of this horrendously strong, not real-world induced signal, chosen specifically for its unique beat frequency against the sample rate and therefore maximal capability to induce jitter (without any regard for the likelihood of such a signal to exist in the home theater environment), the jitter he detects is +/- 10 nanoseconds. The highest frequency to be recovered out of a typical 44 KHz signal is 20 KHz, which is a signal with a period of 50 microseconds. Adding (or subtracting) 10 Ns to the center position of a 50 uS waveform (and mind you, that's absolute worst case, because 20 KHz is the fastest thing to come out of that filter, period) results in time domain distortion that resolves to 4 Hz . or.00005%, which is inaudible (and again, doesn't even hold a candle to what a speaker will do to that signal when it gets hold of it. Doing the same analysis for 20 Hz, we see that the period of 20Hz is 50,000 uS, and when we add 10 uS to that, we get 50,000.01 uS, which is time domain distortion that resolves to 19.999996 Hz, or a.0000002% time domain error. Not only inaudible, just plain irrelevant.
And all of this, of course, is reflected in the pristine visuals and amazing audio we get from high end home theater systems today - even using cheap cables.
I suppose I should own up to what I'm using, as it has become germane: I've got 30 feet of HDMI cable driving a 1080p DLP projector, which in turn produces a 17 foot (205") diagonal image. Plus a bunch of cheap ($6) short cables from various sources to the receiver. I can walk up to that image and put a finger right under a specific pixel and watch the silly thing as long as I have the patience to. I can watch it from a stable source, such as a menu out of the PS3 or a still from a Blueray disk, or I can watch it change with the signal. I can see it in context with its neighbors, and if there were positional jitter (which is what this jitter equates to in video) I'd see it if it were perceptible - and it is not. That's a 30 foot, $60 cable, laid right next to four or five AC lines, some twisted pair control signals for my alarm system, and going by several large fluorescent fixtures in the basement. This is a real-wo
Intersample slew on a D/A isn't a cable issue, Jeff. Signals aren't coming in from a cable and going right into a D/A. There's tons of switching, signal processing (Dolby, EQ, DTS, etc), etc. going on before the D/A ever sees the signal, and by that time, the digital data is clean as a whistle. Intersample slew error is an issue, certainly, but any D/A hardware that produced audible errors would not (just as a for instance) be a component used in a receiver that produces measured THD of fractions of a percent. You understand? The actual measured performance of the whole system at the speaker output jacks, which certainly includes the cables, is about 50x to 500x (depending on your hardware) lower than, for instance, the distortion the speakers add to the signal. The problem you postulate simply does not exist in any meaningful (as in suggesting the listener could ever possibly hear it) way.
In fact, the worst induced phase noise is on the zero crossing, which means that the lowest level signals have the highest distortion.
Jeff, Jeff... The electronics don't give a hoot about the zero crossing. There is no information to be recovered at the zero crossing. They also don't care if the sample window moves a fraction of the window in time one way or the other. The whole point is to sample in the middle of the window, threshold the signal at a rate far higher than the recovered audio, and take that result as gospel. That's the whole process. There is no low level THD in the recovered signal caused by the cables, Jeff. None. It's all in your (very) confused imagination.
Jeff, as I explained to you in my other post, phase noise at 700 KHz - higher, actually - isn't going to produce THD at your speakers. It'd flip bits well before it produced a phase error significant enough to make it past the low pass filters. You're simply wrong.
If you have phase noise on the sample clock, then you have harmonic distortion in the analog output.
There's some misinformation here, all right, but it is you who are the source. You're confusing things across domains.
The digital signal is coming in at a rate much, much higher than the reproduced signal. For instance, if we were dealing with 8-bit audio at 20 KHz, then for every analog sample there are 8 digital bits of a bitstream that have to be recovered. In an uncompressible signal, this requires 8 bits to come in at a rate of 20 KHz. Time must be allowed for this, even in the case where the signal is (at the moment) compressible. So the bitrate has to be eight times higher than 20 KHz. But - Nyquest explanation goes here - the signal can't actually be 20 KHz, it has to be 44 KHz so we can avoid aliasing by filtering. Yet the frequency response of the system is 22 KHz (less, actually, but theoretically, it could be 22 KHz.) Now, if one of those bits, arriving at a bitrate of 8 * 44 KHz, or 352 KHz, jitters (because of the clock) and "arrives late" to quote you, how "late" can it be without shoving the next bit out of the sample recovery slot? The answer is less than 1/2 bit time at 352 KHz - which is 704 KHZ; Now, ask yourself, using that same knowledge you gleaned in basic engineering class: How much of a 704 KHz phase jitter do you think will get through a steep filter at 22 KHz, if indeed the byte being recovered jitters at that rate? The answer of course, is none of it. The rate of change that a 22 KHz filter allows is so slow that signals at hundreds of KHz don't have any effect at all on the signal integration; they're simply too fast and too transient to slew the summing process.
But wait - we're not talking about an 8 bit signal, are we? No. We're talking about a signal that is many bits deeper, and coming a whole lot faster - but still sees a brick wall filter way, way, down low, often still at 20 KHz. So the jitter is even smaller, and the filter is even stronger with respect to it.
Digital domain signals certainly have potential problems, but THD due to jitter isn't one of them in this particular application (hifi and home theater.)
Yes, frequencies are high in a digital cable. Considerably higher than in an analog cable that is trying to carry the same data. However, there are only two states that have to be reliably detected in a digital signal: Is the thing ON, or is it OFF? This means (generally speaking) that at the sample time, which is in the optimal place to catch the change, if the signal simply manages to be in the correct 50% of the range it needs to be in at the right time, it'll be interpreted correctly. Once converted back into a digital one or zero, there is no, repeat no THD or anything else that is a consequence of any distortion that the cable might have introduced. And that conversion happens at the very first digital input the signal is fed to.
The analog cable, however, has no such leeway. Any change in the analog signal comes right through as a change - the black level moves, the dynamic range decreases, images get auras, shadows, high frequency components ring and create repeating echos; analog interference, such as AC signals, CB radios, your local AM station and the crud in the AC lines when you run your vacuum cleaner or air conditioner can all get into the signal and distort it, even when only a tiny bit manages to leak through the shielding. With a digital signal, in order for those same interfering signals to have an effect, the digital signal has to already be degraded to almost 50% or there will probably be no effect at all.
The home theater image itself would tell you instantly if there is effective distortion (meaning, it's changing the bits being detected) that is getting into the signal even if the cable was just carrying visible image data (it isn't!) Because if errors were getting in there, there's no particular reason for them to be bits of low significance; they would be a random mix of all significance, and so you'd see bright spots in dark areas and dark spots in bright areas, errors as high as 50% as the most significant bit errored out. Audio would be the same - there wouldn't be a "little" THD, it would be a freaking mess. Ever watch digital satellite? Notice the huge errors, complete loss of the image frame? That is what happens when you lose bits in a digital transmission, not "increased THD." If the image data is compressed, then the visibility of errors is even worse - that's why satellite images lose partial frames, key frames, and image regions, not just individual pixels.
Clock jitter can introduce THD, sure enough, but that is so easy to avoid it is pitiful. And it isn't a consequence of cables unless the clock itself is carried on the cable, which it generally isn't anyway. No matter if the signal is "buffered" or "re-clocked", in the end, some input takes it as either a one, or a zero and outputs a stable one/zero result, essentially re-thresholding it. If this process works you get a fully reconstructed digital signal of ones and zeros with extremely rare errors (like, one a day.) If it doesn't work, you get an unwatchable, unlistenable signal. Remember that those errors aren't correlated to the data; they can be bits of any significance, they can be lost encryption bits, they can be lost framing or format bits... boom, wreckage.
I run a cheap HDMI cable ($60) 30 feet (the HDMI spec says 32 feet, no more) carrying image data to my 1080p projector; and similarly cheap ($6) but shorter HDMI cables carrying audio and image data from satellite, DVD and a PS3 that also serves as a Blueray player to my receiver. The only signal we ever see any errors on (and they're a huge mess, sure enough) is the satellite signal; we're not at a strong point in the footprint (NE Montana) and we get some pretty good cloud and precipitation combinations, not to mention some solar issues at certain times of the year. These errors aren't a consequence of digital cables.
One more thing: The audio THD in a system can usually be characterized by the THD of the speakers. Most even decent stereo gear has THD
1) the receiver base and treble settings are set flat
Yeah, because everybody knows that if the receiver is tilted, nothing is going to come out straight after that, no matter what angle you place your speakers at.
Both Bootcamp and Parallels require a licensed Windows installation. And the Windows ULA requires the more expensive version of Windows to run on Macs, at least in Parallels.
Yes, you need windows, which is good for MS. Which kind of makes my point. As far as running windows, XP doesn't require that, and XP is what most people continue to use. Even the new computers are beginning to ship with XP again, and it is no problem to get a copy of XP to run under parallels or boot camp. For that matter, if all you want to do is run office, get a copy of windows 98, don't give the virtual environment in Parallels any network, and run office all you want. There are lots of solutions here that use the "real" office if the Mac version were to be discontinued. I really don't see it as a threat.
Yes, MS is afterall a convicted monopolist.
I think you and I have a fundamental disagreement here. MS's "crimes", such as they are, are addressed by the courts. MS's punishments are meted out by the courts. It is not for Apple, or anyone else, to add to those punishments. That's the same attitude that causes a criminal to never be able to get a job again, and I think it is a pathological attitude. If you believe it is impossible to rehabilitate a criminal, then be up front about it and simply say "kill them all!" But if you believe that the legal system has many intermediate cases, then let it do its job and stop worrying about being a vigilante, or encouraging others to be vigilantes. The only reason I can see to patronize Apple over MS or vice versa is the benefits vs cost that we get as consumers of the products being offered.
No, the Mac OS only runs directly on Macs.
...which meant that the user wasn't buying a machine that could run windows, which was stepping on MS's toes, locking them out. However, that's no longer the case. With the new Intel CPU based line, the new Macs can run windows just fine.
It's not "might" see hardware sales drop, they already saw it.
No, it is might. Apple prices are very high; that's what allows clones to get a foot in the door. They have the option to stop doing that. I'd just as soon they did. If the cost of buying a clone is the same as "real Apple hardware", then real Apple sales will continue.
Doesn't matter anyway. As I said elsewhere, I think Jobs is the guiding force here, not the market, not common sense, not even money.
Thanks for the conversation about it. I appreciate your time.
In yours, there's a cheap hardware solution which is probably what should've been done in the first place. (In other words, I'm not sure I can really fault Apple all that much for ignoring your particular problem.)
All right. From that perspective: As it turns out, there isn't such a solution. Or at least, none of the ten or so hardware wifi units I have piled up in the basement have been able to provide one - they won't function inside our firewall (which isn't something that's going to get changed out.) The one that came closest, an old linksys, would work for about two days and then have to be hard reset. Most others won't work at all.
It seems easy enough - the internal LAN, which has quite a few clients on it, is 192.etc, and so the wifi widget needs to be a DHCP Ethernet client on 192.etc and create something else for the wifi clients, typically 10.etc. Generally, it doesn't work at all.
The minis, however, did the right thing for many months, until an OS update which hosed them rather thoroughly. At this point, we don't even have any stable wifi, everything that's always around that was wifi now has an Ethernet cable. My kids can't get on with their laptops any longer, nor can our general run of visitor, unless they sit by an Ethernet jack - and when I wired the house last year, I didn't put any in the guest rooms.:(
I've pretty much given up on the whole thing barring adding an entirely new service provider connection, which I've been resisting. We've got a huge pipe, and I'd like to take advantage of it; however, I'm not buying another one of those. It is one thing to pay to feed the voracious bandwidth appetites of a busy webserver; entirely another to check your email.
Let me also add why I think it is we have not, and are not going to, see OS X for non-Apple hardware: Steve's got a vision of providing everything, staying 100% in control, and as long as Steve is running the show, it's going to be done Steve's way. And Steve is running the show. That's my gut feeling after watching him for decades now.
I own lots of computers. And other stuff. I'm a 50+ year old nerd on slashdot. I run a successful computer software company. Any of this is a surprise to you? Your point? Did you have a point? Hello? Apple should fix, or not fix, their stuff because... Yes? No? Turettes?
Will you buy the rational that if Apple were to release OS X so it ran on beige box PCs, Apple would be stepping on Microsoft's toes, and MS has shown what it will do to competitors?
So, lets say that MS's toes are stepped on. So what can they do? Stop making OS X Office? So what? OO is right there, and Windows Office runs under both boot camp and Parallels anyway. Stop allowing Windows to run on Apple machines? I don't think so. They're not in a position to specify what hardware they run on, or not. And finally, don't you think that by producing a competing OS in the first place, they're *already* stepping firmly on MS's toes?
Or that Apple would see a drop in hardware sales?
They might, at that. So, let's do the math with the cheapest machine in the line, the $600 mini. Sell a copy of Lepoard, make $100. If it breaks, either a download (pennies) or a new DVD (under a dollar) fixes it, plus one programmer's time, more than likely. If they even bother. To make $100 from the mini, they have to have a solid margin in the 20% or so range. But that only breaks it even with the DVD. To do better, they have to make more (and they probably do.) But the mini poses warranty costs, complex supply chain issues, etc... these costs are not duplicated in the software-only side of things. Now, lets look at volume. How many Macs are they going to sell? Now, if they release Lepoard into the wild, as it were, how many of those will they sell? You know as well as I do that they'll sell orders of magnitude more OS copies into the clone market... how much more money do they have to make on hardware, with all its attendant extra costs and vertical integration issues, in order to see that kind of profit? If they sell 2x the copies of the OS, they can make $200 as compared to the margins, whatever they are, on the minis. If they sell 4x the copies, they make $400 (now the mini would have to be $400 of profit out of $600 retail cost... you believe that? I sure don't.) Do you also believe they'd only sell 4x the number of OS copies? My feeling is that they'd sell hundreds of times the OS copies, at least. Especially now, with the dual-boot and Parallels in the wings. So while yes, I think they might see some hardware sales dropoff, I think they'd make more money overall, and I think that's the point of it all anyway.
It doesn't matter what OS you're using: the wifi card in your desktop is not a replacement for a proper access point.
Look, the flexibility, security, performance - or not - of my various attempts at wifi arrangements aside, the fact is, the share capability is busted and Apple hasn't lifted a finger to fix it. That was my point. Try to follow the thread. It's like posting they way you just did, except you actually stay on topic. Dig?
For Apple to make money off of this they will need to greatly downsize the company.
Yes, yes, could not agree more. After all, look at the incredible downsizing Microsoft had to do to become an OS provider. Why, they're so small, you have to be a brownie to get in the building! They operate out of an old, rotting limb on the Keebler elf's tree! You have to pay for the OS by putting milk at your back door! And they employ no one, plus, the stock price always hovers around zero. Billy Gates is in the poorhouse, and no one ever bothers taking Microsoft to court because they downsized so far, there's virtually nothing left. Yessir, gawd help the company that tries to make money off of selling an OS into the market that consists of regular PCs. Especially since Apple, via Parallels (really cool) and Bootcamp (not nearly as cool, but works with games, so has it's own following) can actually use Microsoft's OS and so offers compatibility at a very high level. That's what we're all afraid of, I know, that Apple could get into the same terrible and frightening business position that Microsoft is in. Downsizing it is!
In the case of Apple's computers, they want to be able to give you that happy "Mac Experience" in which things don't go wrong on you.
You know, I see this remark in one form or another all the time, but I don't believe it at all. I'll tell you why.
Our household is Mac-centric; we have 3 mini's and a Macbook Pro. There are other machines here, linux and XP, but we generally use the Macs, the linux machine is a web server, not a desktop. We've run into problems with the Mac's wifi, specifically with the sharing of the connection feature. I've taken the time to document the problems, post them on the Mac forums, report them as bugs, but these problems remain unfixed. These are stock Mac machines with stock Mac wifi hardware. My impression is that Apple doesn't care about my complaints, because the configuration here is, apparently, uncommon. Most people use a wifi-capable router to distribute wifi about their premises, while I elected to use the mini's "share" capability to do it. It worked 100% initially, then an OS upgrade broke it, and it's remained broken since March 2007, despite my poking them in various places such as this (this is only one of many examples - there are other threads, and not just from me, either.) These replies on the Apple forums - not from Apple, from users - were the closest I ever got to help.
I'm right with the program when people say that Apple stuff is remarkably stable. However, I think the credit there should go to the engineers who created the system. There's no apparent company-wide effort to see that things "just work." Lots of things don't work, and haven't for years. There's no unified push to get things that are broken "right." They never added unicode to Appleworks, or really even kept up with it, they just let it die. As of 10.4, network shares haven't been able to refresh after changes for years. Memory (mis)management still causes applications to pig out for tens of seconds at a time. Mail still loses sent mail if you try to use more than one email address. The iPod touch works through the Intel mini's WiFi but not the PPC mini's wifi, same settings all around. Apple's response to this was "use the intel mini" which I consider to be inadequate.
Lest you think I'm just generally Apple bashing, I'm not. I spent years trying to work with Microsoft, both as a user and a developer, and it was MUCH worse. Microsoft sucks so hard my vacuum cleaner ran out in the street and threw itself under the wheels of a passing semi in despair. It is the very reliability of Apple's products out the door - not as a "we'll fix what's broken", but as a "we generally don't ship broken stuff" - that makes the Apple experience what it is.
Consequently, I don't buy the whole "we don't want customers to experience broken OSX, so we won't let it run on generic hardware" rationale. Customers experience broken OSX behaviors all the time, and Apple just lets it run on, likely as not.
People have a very strong tendency to speak up in support of products they have purchased, my guess is because they feel a need to justify having spent money and time and reputation on such a thing. I've heard absolutely worthless justifications over and over for everything from Photoshop to Windows to linux that one way or another, seem to only have obvious value as they reflect the investment in time, money or even public remarks people don't want to back down from. Apple is no more and no less subject to this; once someone buys an Apple, it is my very strong impression that they're going to be pretty positive about having done so. Not just because it works pretty well, which it certainly does, but because money was spent, a decision was made, an internal turning point reached (and there can be factors like terminal frustration with another vendor, such as Microsoft... I'm personally familiar with that feeling, in spades.)
Ha. Funny. I'll tell you what, though, I'd donate some money - hundreds of dollars at least - to a good cause of slashdot's choosing if they would permanently fix the moderation so that moderation isn't anonymous; everyone could see *exactly* who modded what up or down, your average moderator or a slashdot editor/authority. The "low UID" and so forth are essentially useless and require nothing of slashdot either; but they could actually earn a donation from me if they were of a mind to. Not that I think they would, but still, I'll commit to my end of it right here, right now. The worst thing on slashdot is the way the moderation works as a punitive and ideologically driven censorship mechanism. They've been coasting at the user's expense on the current crappy-assed setup for years.
When I throw a party, I see to it that either there is live music, or that someone (sometimes me) is handling the music and/or movie(s) on an individual basis. I consider this part of my responsibility as the host. So this is not a problem for me; instead, it is an opportunity to make my guests more comfortable while hopefully expanding their musical horizons. I certainly would not advocate making all recordings 0 dB with a limited dynamic range in order that I might have more convenient background music playback.
Along these lines, I note that some systems, iTunes for example, allow you to set playback levels on a specific per-tune basis. That's a lovely tool to have, and I wish more playback systems implemented that in one way or another. Add compression, expansion and equalization on a per-tune basis and you have the means to create a music system that performs fairly closely to the way you want it to, if you take the time to work with it.
how exactly does vynil prevent range compression ?
It doesn't. The parent post to yours is 100% incorrect. Compression (and/or expansion) is a process applied to an audio signal. It makes no difference whatsoever where the signal comes from, or is going, or how it is encoded in the sense that compression can, or cannot, be applied. It can be applied once, zero times, or many times. It can be applied in the analog domain or in the digital domain, or both, in any combination. Digital compression needs to be applied to a digital signal (and you can digitize a signal destined for an analog medium before it gets there, or in the process of playing it back, and then reconvert to analog) and analog compression needs to be applied to an analog signal (and you can convert a digital signal to analog, compress it, and then press, or write, the master), or you can take the analog output of the record, compress it in analog or digital fashion, and then listen to it or re-record it. Etc., ad infinitum.
CD's as a release medium may fall back to relatively minor levels, but this has nothing to do with audio quality (reputed or actual.) If it happens, it will be a consequence of digital file transfer capability everywhere from iTunes to bittorrent to swapping flash cards and pocketdrives.
In the end, there will be a market for quite some time for those who prefer CD's for the convenience, stability and physicality of the media, and there will be a market for (new release) vinyl for those who like album covers, hearing pops and groove noise, are accustomed to severely reduced dynamic range, and who never turn the volume up high enough so that the system enters an uncontrollable LF feedback state. Old release vinyl has the unique ability to bring you performances that you can't find on CD, which is entirely another matter. And there will always be a market for wooden knobs that "add to the purity of the sound", cables that "sweeten the music", and various other "audiophile" mythologies-turned-ripoff-scams. Because (a) people don't understand the audio process, and (b) the entire thing is, by its very nature, extremely subjective. So much so that you can barely find an actual review on specifications any longer.
Back to compression. Make no mistake: There is nothing about the CD as a medium that says it needs to be compressed; the significantly higher dynamic range actually allows for less compression than you typically hear on an old-school LP. The fact that you rarely get to experience this is a consequence of various social factors from radio stations which want to be "as loud as that other station" to a general feeling in the recording industry that if you make an uncompressed recording, your recording will sound "too quiet" compared to everyone else's, and so require the listener to adjust their sound system, an inconvenience unthinkable for some reason that has always been completely opaque to me. But then again, I listen to music carefully, not as background that I require be at a particular level of monotony.
The government has managed the news for quite some time, in all manner of creative ways. FEMA simply got caught. Don't think for a moment that this is the first time something like this has been done either by FEMA or by the government in general. They have long been of the mind that the citizens (and the fourth estate, and the constitution) are an inconvenience, rather than supervisory bodies and limits they are responsible to.
Just spend a little time with Google looking for managed news, faked news, and government.
No, they can't. What has confused you is the common tendency of irrational people to characterize themselves as rational, that's all.
Rational people don't believe in things for which there is no evidence of any kind, or for which claimed evidence consistently turns out to be mundane. Just as a rational person does not believe in the existence of a teapot in the shape of a small elephant with my mother's face on it presently orbiting between Jupiter and Mars, no matter how many people claim it is there, a rational person will not believe that there is a god, regardless of the number of others who so believe, or how many books have been written about it, until or unless evidence can be produced to back up the story, to bring the rational person's position of extremely low confidence up a few notches.
Claims for situations extant that lack evidence are stories. Rational people recognize them by this simple, yet manifestly obvious signature: No data. The fact that the signature is obvious is why people who aren't raging intellectuals can recognize it: They don't have to be smart, they just have to be rational. Missouri even puts the process on their license plate: "Show me." It isn't, as they say, rocket science.
Now, if you want to say that many smart people adhere to religious and other supernatural claims, I certainly won't dispute it - that's a fact. But when you say those people are rational... no. Not even close. But in our society, they are free to claim they are, while making any manner of claim they so choose; it's up to you to be rational enough to throw the gauntlet down and say "Show me!"
Slashdot Mirror
No, that can't be it - cts reliably uses caps when he writes articles for Kuro5hin. It has something to do with formal and informal modes of thought. It's just now that I realized that his informal mode of thinking might have been filtered through a cloud of halogen gas. Cl is definitely not your friend as far as breathing and subsequent activities go... :-)
Yes, I read it.
First of all, closely coupled (of neccesity, because magnetic field effects fall off as the square of the distance) induced fields of 6 MHz are not in any way real-world interference for your typical home theater setup. Though I'll come back to that.
Secondly, and as the author of the paper notes, the cable impedance is 50 ohms, and so in order to induce a change in the signal carried inside, the power of the 6 MHz signal has to be fairly extreme in order to induce any change within the cable.
Third, again as the author of the paper notes, the interfering signal is a 6 MHz two volt square wave, something you aren't going to see in a home environment even if there was a 6 MHz signal source. Heck, you won't even find that in most labs unless they're trying to make it, as is the case here.
Fourth, none of this in any way implicates the cable as a source of jitter. It implicates outside signals as a source of jitter; the only related question is, does a really fine cable do a better job of keeping real-world noise (IOW, not a 2 volt, closely coupled, high power square wave) out of your home cables? And the answer, as we all know, is no, it does not. It is trivial to make a cable with a nominal 50-ish ohm impedance on a per conductor basis.
Sixth, home theater HDMI uses differential signaling [TDMS]... so induced signals like this are irrelevant anyway, as they are by their nature common mode.)
Seventh, the paper you have there does not test cables. It tests transformers. There is no question that the recovery interface, when actually different, will provide for different types of recovery. Hence his spread of results over his spread of tested transformers.
Eighth, you should note that even in the case of this horrendously strong, not real-world induced signal, chosen specifically for its unique beat frequency against the sample rate and therefore maximal capability to induce jitter (without any regard for the likelihood of such a signal to exist in the home theater environment), the jitter he detects is +/- 10 nanoseconds. The highest frequency to be recovered out of a typical 44 KHz signal is 20 KHz, which is a signal with a period of 50 microseconds. Adding (or subtracting) 10 Ns to the center position of a 50 uS waveform (and mind you, that's absolute worst case, because 20 KHz is the fastest thing to come out of that filter, period) results in time domain distortion that resolves to 4 Hz . or .00005%, which is inaudible (and again, doesn't even hold a candle to what a speaker will do to that signal when it gets hold of it. Doing the same analysis for 20 Hz, we see that the period of 20Hz is 50,000 uS, and when we add 10 uS to that, we get 50,000.01 uS, which is time domain distortion that resolves to 19.999996 Hz, or a .0000002% time domain error. Not only inaudible, just plain irrelevant.
And all of this, of course, is reflected in the pristine visuals and amazing audio we get from high end home theater systems today - even using cheap cables.
I suppose I should own up to what I'm using, as it has become germane: I've got 30 feet of HDMI cable driving a 1080p DLP projector, which in turn produces a 17 foot (205") diagonal image. Plus a bunch of cheap ($6) short cables from various sources to the receiver. I can walk up to that image and put a finger right under a specific pixel and watch the silly thing as long as I have the patience to. I can watch it from a stable source, such as a menu out of the PS3 or a still from a Blueray disk, or I can watch it change with the signal. I can see it in context with its neighbors, and if there were positional jitter (which is what this jitter equates to in video) I'd see it if it were perceptible - and it is not. That's a 30 foot, $60 cable, laid right next to four or five AC lines, some twisted pair control signals for my alarm system, and going by several large fluorescent fixtures in the basement. This is a real-wo
Intersample slew on a D/A isn't a cable issue, Jeff. Signals aren't coming in from a cable and going right into a D/A. There's tons of switching, signal processing (Dolby, EQ, DTS, etc), etc. going on before the D/A ever sees the signal, and by that time, the digital data is clean as a whistle. Intersample slew error is an issue, certainly, but any D/A hardware that produced audible errors would not (just as a for instance) be a component used in a receiver that produces measured THD of fractions of a percent. You understand? The actual measured performance of the whole system at the speaker output jacks, which certainly includes the cables, is about 50x to 500x (depending on your hardware) lower than, for instance, the distortion the speakers add to the signal. The problem you postulate simply does not exist in any meaningful (as in suggesting the listener could ever possibly hear it) way.
Jeff, Jeff... The electronics don't give a hoot about the zero crossing. There is no information to be recovered at the zero crossing. They also don't care if the sample window moves a fraction of the window in time one way or the other. The whole point is to sample in the middle of the window, threshold the signal at a rate far higher than the recovered audio, and take that result as gospel. That's the whole process. There is no low level THD in the recovered signal caused by the cables, Jeff. None. It's all in your (very) confused imagination.
Jeff, as I explained to you in my other post, phase noise at 700 KHz - higher, actually - isn't going to produce THD at your speakers. It'd flip bits well before it produced a phase error significant enough to make it past the low pass filters. You're simply wrong.
There's some misinformation here, all right, but it is you who are the source. You're confusing things across domains.
The digital signal is coming in at a rate much, much higher than the reproduced signal. For instance, if we were dealing with 8-bit audio at 20 KHz, then for every analog sample there are 8 digital bits of a bitstream that have to be recovered. In an uncompressible signal, this requires 8 bits to come in at a rate of 20 KHz. Time must be allowed for this, even in the case where the signal is (at the moment) compressible. So the bitrate has to be eight times higher than 20 KHz. But - Nyquest explanation goes here - the signal can't actually be 20 KHz, it has to be 44 KHz so we can avoid aliasing by filtering. Yet the frequency response of the system is 22 KHz (less, actually, but theoretically, it could be 22 KHz.) Now, if one of those bits, arriving at a bitrate of 8 * 44 KHz, or 352 KHz, jitters (because of the clock) and "arrives late" to quote you, how "late" can it be without shoving the next bit out of the sample recovery slot? The answer is less than 1/2 bit time at 352 KHz - which is 704 KHZ; Now, ask yourself, using that same knowledge you gleaned in basic engineering class: How much of a 704 KHz phase jitter do you think will get through a steep filter at 22 KHz, if indeed the byte being recovered jitters at that rate? The answer of course, is none of it. The rate of change that a 22 KHz filter allows is so slow that signals at hundreds of KHz don't have any effect at all on the signal integration; they're simply too fast and too transient to slew the summing process.
But wait - we're not talking about an 8 bit signal, are we? No. We're talking about a signal that is many bits deeper, and coming a whole lot faster - but still sees a brick wall filter way, way, down low, often still at 20 KHz. So the jitter is even smaller, and the filter is even stronger with respect to it.
Digital domain signals certainly have potential problems, but THD due to jitter isn't one of them in this particular application (hifi and home theater.)
Someone has fed you a load of nonsense.
Yes, frequencies are high in a digital cable. Considerably higher than in an analog cable that is trying to carry the same data. However, there are only two states that have to be reliably detected in a digital signal: Is the thing ON, or is it OFF? This means (generally speaking) that at the sample time, which is in the optimal place to catch the change, if the signal simply manages to be in the correct 50% of the range it needs to be in at the right time, it'll be interpreted correctly. Once converted back into a digital one or zero, there is no, repeat no THD or anything else that is a consequence of any distortion that the cable might have introduced. And that conversion happens at the very first digital input the signal is fed to.
The analog cable, however, has no such leeway. Any change in the analog signal comes right through as a change - the black level moves, the dynamic range decreases, images get auras, shadows, high frequency components ring and create repeating echos; analog interference, such as AC signals, CB radios, your local AM station and the crud in the AC lines when you run your vacuum cleaner or air conditioner can all get into the signal and distort it, even when only a tiny bit manages to leak through the shielding. With a digital signal, in order for those same interfering signals to have an effect, the digital signal has to already be degraded to almost 50% or there will probably be no effect at all.
The home theater image itself would tell you instantly if there is effective distortion (meaning, it's changing the bits being detected) that is getting into the signal even if the cable was just carrying visible image data (it isn't!) Because if errors were getting in there, there's no particular reason for them to be bits of low significance; they would be a random mix of all significance, and so you'd see bright spots in dark areas and dark spots in bright areas, errors as high as 50% as the most significant bit errored out. Audio would be the same - there wouldn't be a "little" THD, it would be a freaking mess. Ever watch digital satellite? Notice the huge errors, complete loss of the image frame? That is what happens when you lose bits in a digital transmission, not "increased THD." If the image data is compressed, then the visibility of errors is even worse - that's why satellite images lose partial frames, key frames, and image regions, not just individual pixels.
Clock jitter can introduce THD, sure enough, but that is so easy to avoid it is pitiful. And it isn't a consequence of cables unless the clock itself is carried on the cable, which it generally isn't anyway. No matter if the signal is "buffered" or "re-clocked", in the end, some input takes it as either a one, or a zero and outputs a stable one/zero result, essentially re-thresholding it. If this process works you get a fully reconstructed digital signal of ones and zeros with extremely rare errors (like, one a day.) If it doesn't work, you get an unwatchable, unlistenable signal. Remember that those errors aren't correlated to the data; they can be bits of any significance, they can be lost encryption bits, they can be lost framing or format bits... boom, wreckage.
I run a cheap HDMI cable ($60) 30 feet (the HDMI spec says 32 feet, no more) carrying image data to my 1080p projector; and similarly cheap ($6) but shorter HDMI cables carrying audio and image data from satellite, DVD and a PS3 that also serves as a Blueray player to my receiver. The only signal we ever see any errors on (and they're a huge mess, sure enough) is the satellite signal; we're not at a strong point in the footprint (NE Montana) and we get some pretty good cloud and precipitation combinations, not to mention some solar issues at certain times of the year. These errors aren't a consequence of digital cables.
One more thing: The audio THD in a system can usually be characterized by the THD of the speakers. Most even decent stereo gear has THD
Yeah, because everybody knows that if the receiver is tilted, nothing is going to come out straight after that, no matter what angle you place your speakers at.
That's the stuff that burned out your ability to use capital letters, eh? I knew there had to be a reason...
Yes, you need windows, which is good for MS. Which kind of makes my point. As far as running windows, XP doesn't require that, and XP is what most people continue to use. Even the new computers are beginning to ship with XP again, and it is no problem to get a copy of XP to run under parallels or boot camp. For that matter, if all you want to do is run office, get a copy of windows 98, don't give the virtual environment in Parallels any network, and run office all you want. There are lots of solutions here that use the "real" office if the Mac version were to be discontinued. I really don't see it as a threat.
I think you and I have a fundamental disagreement here. MS's "crimes", such as they are, are addressed by the courts. MS's punishments are meted out by the courts. It is not for Apple, or anyone else, to add to those punishments. That's the same attitude that causes a criminal to never be able to get a job again, and I think it is a pathological attitude. If you believe it is impossible to rehabilitate a criminal, then be up front about it and simply say "kill them all!" But if you believe that the legal system has many intermediate cases, then let it do its job and stop worrying about being a vigilante, or encouraging others to be vigilantes. The only reason I can see to patronize Apple over MS or vice versa is the benefits vs cost that we get as consumers of the products being offered.
No, it is might. Apple prices are very high; that's what allows clones to get a foot in the door. They have the option to stop doing that. I'd just as soon they did. If the cost of buying a clone is the same as "real Apple hardware", then real Apple sales will continue.
Doesn't matter anyway. As I said elsewhere, I think Jobs is the guiding force here, not the market, not common sense, not even money.
Thanks for the conversation about it. I appreciate your time.
I didn't make any such claim. I very carefully said that it was my feeling. And I certainly wasn't talking about the laptop market.
All right. From that perspective: As it turns out, there isn't such a solution. Or at least, none of the ten or so hardware wifi units I have piled up in the basement have been able to provide one - they won't function inside our firewall (which isn't something that's going to get changed out.) The one that came closest, an old linksys, would work for about two days and then have to be hard reset. Most others won't work at all.
It seems easy enough - the internal LAN, which has quite a few clients on it, is 192.etc, and so the wifi widget needs to be a DHCP Ethernet client on 192.etc and create something else for the wifi clients, typically 10.etc. Generally, it doesn't work at all.
The minis, however, did the right thing for many months, until an OS update which hosed them rather thoroughly. At this point, we don't even have any stable wifi, everything that's always around that was wifi now has an Ethernet cable. My kids can't get on with their laptops any longer, nor can our general run of visitor, unless they sit by an Ethernet jack - and when I wired the house last year, I didn't put any in the guest rooms. :(
I've pretty much given up on the whole thing barring adding an entirely new service provider connection, which I've been resisting. We've got a huge pipe, and I'd like to take advantage of it; however, I'm not buying another one of those. It is one thing to pay to feed the voracious bandwidth appetites of a busy webserver; entirely another to check your email.
Citation? Or are you just rambling here?
Let me also add why I think it is we have not, and are not going to, see OS X for non-Apple hardware: Steve's got a vision of providing everything, staying 100% in control, and as long as Steve is running the show, it's going to be done Steve's way. And Steve is running the show. That's my gut feeling after watching him for decades now.
I own lots of computers. And other stuff. I'm a 50+ year old nerd on slashdot. I run a successful computer software company. Any of this is a surprise to you? Your point? Did you have a point? Hello? Apple should fix, or not fix, their stuff because... Yes? No? Turettes?
So, lets say that MS's toes are stepped on. So what can they do? Stop making OS X Office? So what? OO is right there, and Windows Office runs under both boot camp and Parallels anyway. Stop allowing Windows to run on Apple machines? I don't think so. They're not in a position to specify what hardware they run on, or not. And finally, don't you think that by producing a competing OS in the first place, they're *already* stepping firmly on MS's toes?
They might, at that. So, let's do the math with the cheapest machine in the line, the $600 mini. Sell a copy of Lepoard, make $100. If it breaks, either a download (pennies) or a new DVD (under a dollar) fixes it, plus one programmer's time, more than likely. If they even bother. To make $100 from the mini, they have to have a solid margin in the 20% or so range. But that only breaks it even with the DVD. To do better, they have to make more (and they probably do.) But the mini poses warranty costs, complex supply chain issues, etc... these costs are not duplicated in the software-only side of things. Now, lets look at volume. How many Macs are they going to sell? Now, if they release Lepoard into the wild, as it were, how many of those will they sell? You know as well as I do that they'll sell orders of magnitude more OS copies into the clone market... how much more money do they have to make on hardware, with all its attendant extra costs and vertical integration issues, in order to see that kind of profit? If they sell 2x the copies of the OS, they can make $200 as compared to the margins, whatever they are, on the minis. If they sell 4x the copies, they make $400 (now the mini would have to be $400 of profit out of $600 retail cost... you believe that? I sure don't.) Do you also believe they'd only sell 4x the number of OS copies? My feeling is that they'd sell hundreds of times the OS copies, at least. Especially now, with the dual-boot and Parallels in the wings. So while yes, I think they might see some hardware sales dropoff, I think they'd make more money overall, and I think that's the point of it all anyway.
Look, the flexibility, security, performance - or not - of my various attempts at wifi arrangements aside, the fact is, the share capability is busted and Apple hasn't lifted a finger to fix it. That was my point. Try to follow the thread. It's like posting they way you just did, except you actually stay on topic. Dig?
Yes, yes, could not agree more. After all, look at the incredible downsizing Microsoft had to do to become an OS provider. Why, they're so small, you have to be a brownie to get in the building! They operate out of an old, rotting limb on the Keebler elf's tree! You have to pay for the OS by putting milk at your back door! And they employ no one, plus, the stock price always hovers around zero. Billy Gates is in the poorhouse, and no one ever bothers taking Microsoft to court because they downsized so far, there's virtually nothing left. Yessir, gawd help the company that tries to make money off of selling an OS into the market that consists of regular PCs. Especially since Apple, via Parallels (really cool) and Bootcamp (not nearly as cool, but works with games, so has it's own following) can actually use Microsoft's OS and so offers compatibility at a very high level. That's what we're all afraid of, I know, that Apple could get into the same terrible and frightening business position that Microsoft is in. Downsizing it is!
[cough]
You know, I see this remark in one form or another all the time, but I don't believe it at all. I'll tell you why.
Our household is Mac-centric; we have 3 mini's and a Macbook Pro. There are other machines here, linux and XP, but we generally use the Macs, the linux machine is a web server, not a desktop. We've run into problems with the Mac's wifi, specifically with the sharing of the connection feature. I've taken the time to document the problems, post them on the Mac forums, report them as bugs, but these problems remain unfixed. These are stock Mac machines with stock Mac wifi hardware. My impression is that Apple doesn't care about my complaints, because the configuration here is, apparently, uncommon. Most people use a wifi-capable router to distribute wifi about their premises, while I elected to use the mini's "share" capability to do it. It worked 100% initially, then an OS upgrade broke it, and it's remained broken since March 2007, despite my poking them in various places such as this (this is only one of many examples - there are other threads, and not just from me, either.) These replies on the Apple forums - not from Apple, from users - were the closest I ever got to help.
I'm right with the program when people say that Apple stuff is remarkably stable. However, I think the credit there should go to the engineers who created the system. There's no apparent company-wide effort to see that things "just work." Lots of things don't work, and haven't for years. There's no unified push to get things that are broken "right." They never added unicode to Appleworks, or really even kept up with it, they just let it die. As of 10.4, network shares haven't been able to refresh after changes for years. Memory (mis)management still causes applications to pig out for tens of seconds at a time. Mail still loses sent mail if you try to use more than one email address. The iPod touch works through the Intel mini's WiFi but not the PPC mini's wifi, same settings all around. Apple's response to this was "use the intel mini" which I consider to be inadequate.
Lest you think I'm just generally Apple bashing, I'm not. I spent years trying to work with Microsoft, both as a user and a developer, and it was MUCH worse. Microsoft sucks so hard my vacuum cleaner ran out in the street and threw itself under the wheels of a passing semi in despair. It is the very reliability of Apple's products out the door - not as a "we'll fix what's broken", but as a "we generally don't ship broken stuff" - that makes the Apple experience what it is.
Consequently, I don't buy the whole "we don't want customers to experience broken OSX, so we won't let it run on generic hardware" rationale. Customers experience broken OSX behaviors all the time, and Apple just lets it run on, likely as not.
People have a very strong tendency to speak up in support of products they have purchased, my guess is because they feel a need to justify having spent money and time and reputation on such a thing. I've heard absolutely worthless justifications over and over for everything from Photoshop to Windows to linux that one way or another, seem to only have obvious value as they reflect the investment in time, money or even public remarks people don't want to back down from. Apple is no more and no less subject to this; once someone buys an Apple, it is my very strong impression that they're going to be pretty positive about having done so. Not just because it works pretty well, which it certainly does, but because money was spent, a decision was made, an internal turning point reached (and there can be factors like terminal frustration with another vendor, such as Microsoft... I'm personally familiar with that feeling, in spades.)
There's another
Ha. Funny. I'll tell you what, though, I'd donate some money - hundreds of dollars at least - to a good cause of slashdot's choosing if they would permanently fix the moderation so that moderation isn't anonymous; everyone could see *exactly* who modded what up or down, your average moderator or a slashdot editor/authority. The "low UID" and so forth are essentially useless and require nothing of slashdot either; but they could actually earn a donation from me if they were of a mind to. Not that I think they would, but still, I'll commit to my end of it right here, right now. The worst thing on slashdot is the way the moderation works as a punitive and ideologically driven censorship mechanism. They've been coasting at the user's expense on the current crappy-assed setup for years.
When I throw a party, I see to it that either there is live music, or that someone (sometimes me) is handling the music and/or movie(s) on an individual basis. I consider this part of my responsibility as the host. So this is not a problem for me; instead, it is an opportunity to make my guests more comfortable while hopefully expanding their musical horizons. I certainly would not advocate making all recordings 0 dB with a limited dynamic range in order that I might have more convenient background music playback.
Along these lines, I note that some systems, iTunes for example, allow you to set playback levels on a specific per-tune basis. That's a lovely tool to have, and I wish more playback systems implemented that in one way or another. Add compression, expansion and equalization on a per-tune basis and you have the means to create a music system that performs fairly closely to the way you want it to, if you take the time to work with it.
It doesn't. The parent post to yours is 100% incorrect. Compression (and/or expansion) is a process applied to an audio signal. It makes no difference whatsoever where the signal comes from, or is going, or how it is encoded in the sense that compression can, or cannot, be applied. It can be applied once, zero times, or many times. It can be applied in the analog domain or in the digital domain, or both, in any combination. Digital compression needs to be applied to a digital signal (and you can digitize a signal destined for an analog medium before it gets there, or in the process of playing it back, and then reconvert to analog) and analog compression needs to be applied to an analog signal (and you can convert a digital signal to analog, compress it, and then press, or write, the master), or you can take the analog output of the record, compress it in analog or digital fashion, and then listen to it or re-record it. Etc., ad infinitum.
CD's as a release medium may fall back to relatively minor levels, but this has nothing to do with audio quality (reputed or actual.) If it happens, it will be a consequence of digital file transfer capability everywhere from iTunes to bittorrent to swapping flash cards and pocketdrives.
In the end, there will be a market for quite some time for those who prefer CD's for the convenience, stability and physicality of the media, and there will be a market for (new release) vinyl for those who like album covers, hearing pops and groove noise, are accustomed to severely reduced dynamic range, and who never turn the volume up high enough so that the system enters an uncontrollable LF feedback state. Old release vinyl has the unique ability to bring you performances that you can't find on CD, which is entirely another matter. And there will always be a market for wooden knobs that "add to the purity of the sound", cables that "sweeten the music", and various other "audiophile" mythologies-turned-ripoff-scams. Because (a) people don't understand the audio process, and (b) the entire thing is, by its very nature, extremely subjective. So much so that you can barely find an actual review on specifications any longer.
Back to compression. Make no mistake: There is nothing about the CD as a medium that says it needs to be compressed; the significantly higher dynamic range actually allows for less compression than you typically hear on an old-school LP. The fact that you rarely get to experience this is a consequence of various social factors from radio stations which want to be "as loud as that other station" to a general feeling in the recording industry that if you make an uncompressed recording, your recording will sound "too quiet" compared to everyone else's, and so require the listener to adjust their sound system, an inconvenience unthinkable for some reason that has always been completely opaque to me. But then again, I listen to music carefully, not as background that I require be at a particular level of monotony.
Yes, certainly. We call this "being irrational."
The government has managed the news for quite some time, in all manner of creative ways. FEMA simply got caught. Don't think for a moment that this is the first time something like this has been done either by FEMA or by the government in general. They have long been of the mind that the citizens (and the fourth estate, and the constitution) are an inconvenience, rather than supervisory bodies and limits they are responsible to.
Just spend a little time with Google looking for managed news, faked news, and government.
No, they can't. What has confused you is the common tendency of irrational people to characterize themselves as rational, that's all.
Rational people don't believe in things for which there is no evidence of any kind, or for which claimed evidence consistently turns out to be mundane. Just as a rational person does not believe in the existence of a teapot in the shape of a small elephant with my mother's face on it presently orbiting between Jupiter and Mars, no matter how many people claim it is there, a rational person will not believe that there is a god, regardless of the number of others who so believe, or how many books have been written about it, until or unless evidence can be produced to back up the story, to bring the rational person's position of extremely low confidence up a few notches.
Claims for situations extant that lack evidence are stories. Rational people recognize them by this simple, yet manifestly obvious signature: No data. The fact that the signature is obvious is why people who aren't raging intellectuals can recognize it: They don't have to be smart, they just have to be rational. Missouri even puts the process on their license plate: "Show me." It isn't, as they say, rocket science.
Now, if you want to say that many smart people adhere to religious and other supernatural claims, I certainly won't dispute it - that's a fact. But when you say those people are rational... no. Not even close. But in our society, they are free to claim they are, while making any manner of claim they so choose; it's up to you to be rational enough to throw the gauntlet down and say "Show me!"