What is the engineering justification for that specification? Why not .01 db or .001 db. Where does that come from?
I just like the sound of .1dB. Have been doing it for 30 years. Too old to change. However, how do I get it right, everyone? I use my trusty HP3563, set it to audio sweep and note the deviations. Looks like the Rocky Mountains still!
I'm not surprised. But my question to JC is what demonstrated criteria is the specification based on. An engineer defines requirements based on some functional need. He doesn't wet his finger and stick it in the air to see which way the wind is blowing that day. So what I'd like to know is how did JC arrive at his spec? If he were to tell me that a documented study shows that 95% of people can hear a difference of +/- 0.2 db at 20khz and he wanted a 100% safety margin then I could accept that. What I can't accept is that he tells me in one breath he's an engineer and in another that he selects a performance specification that his equipment must meet out of thin air because that's what he likes or because that's "his" experience. Engineers, that is real ones have a rational reason for what they do. If they don't, then it's not engineering. It may be advertising but it's not engineering.
Specific tests may not be valid for a number of reasons. The science isn't sufficiently advanced to devise meaningful tests that examine salient variables. The tests fail to simulate real world conditions but are inherited from a more primitive time when they were once meaningful. There are more variables in the test procedure than it controls and one variable at a time is not being tested but multiple variables are at work simultaneously. There are others.
That tests are flawed does not negate the fact that they are the only reliable way to determine the limits of perception among those being tested. The claim of the so called subjectivists is that the process of testing itself is not valid. Nothing could be further from the truth. The problem for someone who genuinely believes he has made a discovery or devised something truly innovative is to devise a test which proves it. That is exactly the opposite of what audiophiles do. They only use tests and measurements to justify opinions when it is convenient to prove a point they arrived at irrationally and when the opposite is true, they reject the idea that tests prove anything. Now what about that blowtorch preamplifier?
Let's examine that statement.
Ultimately, the end goal is to sell product and make money.
That requires marketing and advertising.
And in this market, as with many others sadly, playing the numbers game is a highly effective marketing tool.
The numbers are achieved through engineering.
Therefore, does the engineer in this case not have a rational reason for what they do?
Surely you're not arguing that the desire to make money is irrational are you?
se
I hate to say it guys, but the reason I use .1dB is because I can, with 1% parts and a good engineering design that optimizes the tradeoffs. That is all there is to it. The very idea that Lipshitz might think that it is important, only contributes to my effort. After all, RIAA has been essentially defined by Lipshitz and Jung. That is what I use to map to.
Here is evidence that at least one cutting room uses a second order rolloff on the lathe.
Combined with the infamous "Neumann Pole" the result is worse then leaving it alone.
Cut and Thrust: RIAA LP Equalization | Stereophile.com
Combined with the infamous "Neumann Pole" the result is worse then leaving it alone.
Cut and Thrust: RIAA LP Equalization | Stereophile.com
In my vocabulary, that just about sums up an engineer.
While on the other hand, you seem to view an engineer and a scientist as one and the same.
Must be a language barrier thing.
Hi wavebourn,
True, but bear in mind that it is not just harmonics that must be considered; we don't just listen to sine waves, so IM products are important. Their specing can be entirely different from things they may mask. This is why it is wrong for people to suggest that 20 kHz THD doesn't matter even if they don't thing signals above 20 kHz are audible. Where you have 20 kHz THD, you will surely hear IM as well, which can easily fall in-band.
This is one reason I strongly prefer the 19+20kHz CCIF test with spectral analysis. This approach to evaluating amplifier distortion is even more important with the advent of class D amplifiers with output filters which may attenuate the THD harmonics.
Cheers,
Bob
19+20kHz CCIF test is better than only THD, but it's not enough, because of it ignores transients that are present in music signals.
...and proved usually implies some form of measurement that either accepts or refutes the null hypothesis.
I'm sorry I didn't follow your train of thought. Let me make up for it, 20,001 cycles per second! 🙂
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OK SY,
So you never did get back to me on if the wet playing induced noise in a record decreases from the start groove to the inner. Your theory that it is a property of velocity should have the noise decrease by more than 10 db. Should be obvious even with out test gear.
Now you doubt my completely scientific demonstration with every know and several previously unknown variables well controlled. Eh! Try it for yourself. I think you will quickly understand why it is not described as a sound but is noticed.
After that I'll mention how low frequencies can make folks queasy. Great for a Halloween haunted house.
ES
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As soundminded, crudely tried to point out - I'm from Ireland (don't know where Trolls are from?) & part of the Irish mythology is that we aren't English 😀
You'd have to go through all the issues, decide which articles you wanted, and then buy them at $20 a pop.
They do have an anthology on disk recording in two volumes for $74, but they're currently out of stock.
se
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