DaveLew

What nonsense, that's so off base it's not even wrong

How do you know that what you're seeing was captured by microphones, and not the artifact of some signal processing. More important, what objective information do you have that show that you could distinguish between is a cd res version and a high res version.

It can only reproduce a square wave if it's sample rate is infinity.

Well KK, you should read Bettelheim. Myth is important, but not when its comes to hearing acutity to sell products. Chris's observation, sure musical instruments produce higher frequency harmonics that depending on the room and your distance from the instrument or if you're at a concert and its cold so lots of people have overcoats and so on, change the sound you can hear or that a microphone picks up. Once that's done, its game over for supersonic. All those Neuman microphones that are so beloved in every studio top off at 20 KHz, except for those places that still love the hum and distortion of tubes. They still use u67s with power supplies, and those are good for 15KHz. Oh, one other aside. Some one made some comment about looking at a square wave with an oscilloscope. A square wave is actually a set of sine wave with harmonics off to infinity. No wonder he was confused.

There's actually pretty basic science on sampling rate requirements. Human hearing pretty much tops out at about 20KHz, except for most of the middle aged or older people (including myself) posting here, and we're lucky to hear 15K or so. To completely describe an analog signal numerically, you need to sample it at twice its frequency, no more. That's settled science, as settled as Ohm's law. That's how the 44 k or so for standard cd audio was chosen. Your German Shepherd may appreciate the 40 KHz that 96 k gives you and your pet bat may love 80 or 160 KHz that 192k or the 384k mentioned gives you, but how much you'll hear is much more in doubt. There's actually pretty basic science on sampling rate requirements. Human hearing pretty much tops out at about 20KHz, except for most of the middle aged or older people (including myself) posting here, and we're lucky to hear 15K or so. To completely describe an analog signal numerically, you need to sample it at twice its frequency, no more. That's settled science, as settled as Ohm's law. That's how the 44 k or so for standard cd audio was chosen. Your German Shepherd may appreciate the 40 KHz that 96 k gives you and your pet bat may love 80 or 160 KHz that 192k or the 384k mentioned gives you, but how much you'll hear is much more in doubt. The 16 bits of dynamic range, which comes out to something over 90 db is also pretty much the limits of human hearing. The high res 24 bits give you 140+ db. That starts at inaudible and ends at the sound level produced by a launch of the space shuttle. If you're doing lots of signal processing, such as in a recording studio, that extra headroom and bandwidth might come in handy. If it’s just a matter of listening to music, the benefits of anything above standard cd resolution are at best questionable . In fact, the only study I've seen comparing standard cds to high res shows no one can hear difference. I know the backbenchers have complained about aspects of the study, but no one has done the work to need to confirm or refute it.

Interesting, but does the extra 6 db at "higher" frequencies (how high?) matter. Unless the extra 6 db lowered the error rate enough to increase thruput it doesn't The cost of cable is a tiny part of the cost of any data center, a 3x in cost is noise level. I would say that the fact it isn't made is proof it doesn't matter.

routers, switches, special nic chips..... You guys might take the a moment to remember how ethernet operates. Packets can be delayed based on traffic, they can arrive out of order. The only thing you can depend on is reliable delivery. h

ziggyzack, you have to love the high end market. Its the perfect storm of greedy vendors and gullible customers.

Your claim was 6a gave you better reliabilty than 6 at 1 GB, that claim wasn't supported by your posting. It's well accepted that 6 is better for 1 GB and 6a is necessary for 10 GB.

Well Chris. First, I'm with a prop trading group, not a bank or a brokerage. We pay for trades just like every one else although I will tell you that with exchange liquidity rebates there are strategies where the rebate exceeds the trade cost. You can make money in a flat market by just making lots of trades. Second, I used to be with a vc firm in the valley. I know the economics of manufacturing electronic equipment, and I know the cost of goods for a $5,000 dac is in the 100s of dollars, that's an unheard of markup. Oh, the USB issue is confusing because it seems an obvious fix to the "jitter" problem is being ignored, why don't they design a dac with a big front end buffer?

Actually Chris, the spec is that you don't need 6a until you hit 10 GB, in fact cat 5 is fine for 1 gb. You must know something that the people writing the spec and the vendors in a multi billion dollar a year industry don't know. I accept their judgement, since you don't, you should do the measurements to prove them wrong.

The usb issue has always confused me. USB 2 bandwidth is at least an order of magnitude faster than the most demanding audio encoding. Why can't DACs be designed with a big buffer that can be always kept full and that buffered data is fed to a dac at the precise rate with zero jitter, problem solved. Given the huge markups relative to the cost of goods of high end audio equipment, the 5 or 10 dollars the buffering will cost won't matter. In fact, why don't they spend a few dollars more and support streaming flac or some other lossless compression.

I know our tech guys connect equipment on our desk with 1 GB and it's all cat 6. They even test connections with a handheld error rate measurement box. You want to compare error rates, get hold of one and do the test yourself. What I know is that even cat 5 is speced for 1 GB. I also know that, given that a bad trade caused by a data problem can cost us 7 figures or more, if we needed cat 6a, we'd get it. We don't, and unless you're running 10 GB, you don't either.

With all due respect, but you've just repeated the standard high end salesperson looking for his commission "golden ears" sales pitch. Its a standard technique where the sales person will describe how with discerning hearing the difference is obvious and how after purchasing it you too will develop golder ears. You claim you can reliabily tell the difference between speaker cables, how have you tested that claim? You just put this to a test, hide the cables so you can't see them, have someone switch them, and see if your identifications are better than random.

The wine example is very appropriate. It's well know that the amount of fraud in the high end wine market is quite remarkable. Instead of selling you speaker cables costing 5 figures that sound no different than a $20 cable, they place decent claret in an old bottle and sell it as lafite. And of course there's that famous study where the quality rating wine "experts" gave wines were better when they were told the wine was more expensive, a judgement backed up by functional mri studies showing there was a physical basis for the misjudgement.