DACs and reproduced sound
The Benchmark has some good things as well as some budget compromises inside. There is an active aftermarket of modifiers offering upgrades in areas like soft recovery diodes, Bybees, op amps, and chassis sheilding. Modified units have received good reviews. http://www.odysseyaudiohk.com/cgi-bin/yabb/YaBB.pl?num=1246198439 |
I have a strong personal policy of not making "ad hominem" arguments, i.e., debating a point by attacking the person making the point, rather than the point itself. However, in this case it should be pointed out that the comment quoted in Dangelod's initial post was made by Peter Aczel, The Audio Critic. Twenty-five or so years ago, Mr. Aczel's reviews routinely and intensively delved into the subtle sonic nuances and differences which he perceived as characterizing the sound of electronic audio components. In more recent years, however, he metamorphosed to the extreme opposite end of the audiophile ideological belief spectrum, maintaining very assertively that all electronic components meeting basic measurable standards of performance will sound identical. Mr. Aczel is a very intelligent person, and he writes extremely well and very persuasively. His "day job" long ago was that of an advertising writer. But nevertheless he can often be completely wrong, as evidenced for starters by these diametrically opposed positions he has taken about electronic components over the years. And (to Shadorne), no he was not talking about just the analog preamp section. Here is a quote from his concluding paragraph, to cite just one of many statements in the review which make that clear: All in all, the Benchmark DAC1 HDR is damn close to a perfect piece of equipment. Neither its digital performance nor its analog performance could be meaningfully improved. That’s really all that needs to be said. Kijanki said: Important to remember is that there is no perfect DAC and everything is a compromise (and very complicated). Listening test will give you much more than reading specs. I second this 100%. To get an idea of the kinds of complexity and subtle technical factors which are involved, begin by flipping through this 39 page datasheet for a family of advanced dac chips: http://focus.ti.com/lit/ds/symlink/pcm2707.pdf And then take a look at these excellent whitepapers from Ayre: http://www.ayre.com/PDF/Ayre_MP_White_Paper.pdf http://www.ayre.com/PDF/Ayre_USB_DAC_White_Paper.pdf And consider that the dac datasheet is just for an integrated circuit chip, and doesn't begin to address the complexities and potential design pitfalls of the surrounding circuitry. And consider that the least significant bit of just a 16-bit dac provides a resolution of 1 part in 65,536, which is 0.0015% of the upper limit of its output range ("full scale"), and the least significant bit of a 24 bit dac provides a resolution of 1 part in 16,777,216, which is 0.000006% of full scale. There are innumerable ways in which the accuracy which that resolution can theoretically provide can be and will be vastly degraded, both within the dac device, and in the surrounding circuitry. Real-world devices simply aren't that accurate. Regards, -- Al |
Real-world devices simply aren't that accurate. Agreed. However at around 1% distortion we start to have trouble to hear or identify distortion. At best speakers may have 0.3% distortion over their entire frequency operating range at full power (if they are exceptional quality). Perhaps the point Peter is making is that extra ultra precision in modern line level analog equipment can quickly approach "diminishing returns" given the acuity of our hearing and the relatively crap performance of speakers and room acoustics in general... Agreed, "perfect" is completely the WRONG word... as Kijanki points out NOTHING IS PERFECT... (except my wife and kids) "Good Enough given the sad inadequacies of other audio system equipment" is more like it but "Perfect" ....certainly and absolutely NOT. |
I think that this is an interesting technical discussion, lots of information. I keep on thinking that if God came down with the perfect DAC, none of us would probably like it. The whole Analog to Digital Recording process, plus the Digital to Analog conversion, has consistently removed Harmonic Content and Decay. Some of the best DACs have tried to reproduce what little Harmonic Content there is on the CD Disk. I believe that some utilize their Analog Output Stages, to overemphasize the little Harmonic Content there is. I don't bear any grudges to the changes from the original, because the Digital Process is so largely damaging to the Harmonic Content, that any exaggeration in the opposite direction is an improvement, within reason of course. This is why, I believe that if God did provide the perfect DAC, it would be the perfect magnifying lense to all of the huge warts of the Digital Recording Medium. More accuracy only exposes less and less Harmonic Content that is inherit in the Digital Recording itself. You might have the perfect DAC, but you probably wouldn't like it! |
