Is "High-End" audio a scam? - Page 59  

I understand jitter as the musical notes being in the right place, but at the wrong time.

I am not an expert on this, you should probably talk to an oscillator designer for all the technical information. But clocks are measured in long term stability, as I described above, and short term stability which is what is more commonly known as jitter. The short term stability, or jitter, causes phase noise distortion. Both long term and short term stability are important factors.

Don't forget that a non thermally controlled oscillator will perform at different specs depending on what the temperature is, which is why TCXOs are more accurate. We don't know when the batch of oscillators were manufactured or how long they were sitting on the shelf before they were installed.

There's a lot of debate on how much of this is actually audible but I am confident in the differences I heard after experimenting with clocks. The Transporter uses two, so I removed them and replaced them with two Audio-gd JZ1 boards running at different frequencies. This was a cheap investment as the boards were only like $20 each and the power supply board was about the same price. They are very similar to the $100 Burson clocks, but I don't know which came first, the chicken or the egg. I've also had caps replaced on these boards. There's a company called Dexa that makes their Neutron Star clock and I think it's upwards of $600. The external Antelope Audio clocks are in the high thousands.

I think the Audio-gd ones are just fine though and work great in my system. I honestly don't know if the slightly more accurate Neutron Star would sound better or not. I'm very content with my system now and don't feel I need to make any more changes. If you're iPod satisfies you, that's all that matters. We each have different wants and requirements and we each take different approaches to getting there. Live and let live, I say.

As a single tone or note, no way. That would be virtually impossible unless you were a freak of nature musical prodigy.

As an entire song I think the above, along with phase noise contributes to fatigue, improper imaging, poor soundstage, etc., which I feel I can hear and so do many others. And I think it is the main reason people find fault with digital gear and the vinylphiles stay their course. I could never be a vinyl guy, the clicks and pops, and it's a pain in the ass, and there is no debating the fact that digital is more accurate and has a much higher SNR. Still, vinyl guys hear something that they like and even though they hear clicks and pops and aren't hearing perfect reproduction, they aren't hearing phase noise and I think that's what drives a lot of vinyl guys crazy about digital gear. Eliminate virtually all the phase noise, they might enjoy it more.

you think vinyl has perfectly accurately reproduced phase!?  no electric motor on the planet could come anywhere close to keeping an A440 tone between 439.9998 Hz and 440.0002 Hz!  Not by a long shot

 

Right, but I'm talking about phase noise generated by an oscillator circuit, not just random pitch oscillation from the motor.

I'm not a vinyl guy so I don't know much about things like wow & flutter, or RIAA equalization. I just know that to many vinylphiles digital gear sounds intolerable or at the very least, not as good. If you try to debate me on the specifics of turntables, I'll most certainly lose.

Bigshot,

Here's something I found awhile ago that talks about oscillator stability better than I can, and it's only a few pages:

http://www.cardinalxtal.com/static/frontend/files/cardinal-clock-stability.pdf

I don't know about phase noise but a minute change in pitch like that won't make a lick of difference. Pitch I know inside and out from 78s. There are people with perfect pitch, but nowhere near that perfect. Ten or twenty cents maybe, but nowhere near the figure above.

As for jitter, I spent a solid week puzzling that out, and I came away astounded that anyone could possibly take something measured in picoseconds seriously. When I hear words like listening fatigue, imaging and soundstage, you start to lose me.

Can what you're talking about be put into concrete terms with attention to scale and clear perceptual thresholds? That's what I'm looking for here.

Well I guess not then since you think an iPod sounds as good as any good DAC.

It's hard to say. There is no such thing as a free lunch, and the trade off here may be the digital filter phase response.

 

The two cascaded 3rd order analog low pass filters don't seem out of this world. But the digital filter is a different story. The system is 16x oversampled from 48kHz, which means the digital low pass filter needs to cut-off at fs/32. That in itself requires a high order filter (possibly why an FIR was out of the question.) Such an IIR filter will likely come with the price of severe phase distortion. They say they have "additional poles" "to prevent too much phase shift occurring at the audio band." And no plot or characterization is given as to the effectiveness of this compensation.

 

They have gained in stop-band rejection, but now they have to deal with a non-trivial phase distortion problem it seems. 

Edited by ultrabike - 7/24/12 at 11:17pm

I've heard people go on and on about warmth, digital listening fatigue, ridiculously wide frequency response, infinite sampling rates, and the like... As a longtime vinyl fan, I can tell you with a high degree of certainty that stuff is complete and utter hogwash. Vinyl has a narrower frequency response, higher noise, higher distortion, greater pitch variation, and a narrower dynamic range than digital. There is nothing about sound that vinyl does better than digital.

The people who wax romantic about the glorious vinyl are the ones who know the least about what they are talking about. Folks who use spec sheets to measure gnat wings are closer to the truth than record fetishists. There is one reason to collect records, and one reason only- to get music that isn't available on CD.

I'm a "rekkid guy". I have over 15,000 records dating back over 100 years. I have a variety of record players ranging from a 1914 cabinet Victrola VV-X to classic Dual and Thorens tables. I love shellac and vinyl. I know all about all types of records. But records most emphatically do *not* sound better than CDs. The format is capable of sounding very good, but CD sound done right totally smokes it. If a record sounds better than a CD ofthe same material, the CD has been poorly mastered. The CD format is vastly superior to vinyl.

I don't own a DAC, so I won't comment on that. But here is what I know...

I took my iPod Classic and loaded an AIFF rip on it. I set up a line level matched A/B test against my best SACD/CD player playing the same CD. No difference.

Then I did the same thing with a Pentatone DSD SACD hybrid in my SACD player and a duplicate playing the redbook layer in my inexpensive CD player.

Then I took 24 bit audio in a ProTools workstation. I bounced it down to 16 bit and burned a CD. Then I did a direct line level matched test between 24 bit native and the burned CD on my CD inexpensive player, and determined that there was no audible difference.

According to my logic 24 bit = SACD = CD = iPod.

Would there be any reason to believe that a DAC would sound better than a ProTools workstation playing back a native 24 bit file? I haven't thought of any reason why that would be the case myself. That's why I've never bothered to buy a DAC.

It's been my experience that digital audio meets or exceeds every audible aspect of sound reproduction. I've compared every CD player I've owned to the one it was replacing and they all sounded identical, so I've determined that it's very consistent. That's why I suspect that if and when I do find something that sounds different, the different player is probably going to be the unit with the problem, not every other CD player I've ever owned.

Is my logic sound here?

Your logic is sound but it goes back to the same story as always. We all hear different gear differently, and some is more transparent and retrieves more detail than others. This debate will never end, nor will the one about hearing things we just may not be able to measure yet. It's an unwinnable argument since we all hear differently, whether it's our ear shape, or tone maps in our brain, or placebo, or all three. You just have to agree to disagree.


I have no dispute with you here at all. I agree with everything you said. My earlier point was just that vinylphiles don't, for the most part. There is no disputing the technical superiority of digital. Just like tubes, some prefer their "warmth" when a transistor-based component can emulate any tube sound.

I think it goes back to a different story... Some people go to great lengths to find out for themselves what various technologies really sound like, and others trust the numbers on a page given to them by an equipment manufacturer.

The most important specification in any home stereo are the thresholds of human perception. Without those, you can go down all sorts of rabbit holes chasing imperceptable picoseconds, inaudibly high frequencies, inhmanly broad dynamic ranges, and noise floors twenty miles below the Earth's crust. Without the benchmark of our ears, theories and numbers are meaningless.

But that's what I'm talking about. We ultimately must use our ears to decide and only let specs point the way. People who buy on spec alone aren't always happy with what they end up with. I listened to a LOT of gear, a real lot, before I decided on what I like best. It was a long journey but I'm very content now, and it took a long time before I was fully content. Sure, I may change my preferences again one day but at least I know it won't be anytime soon.

It sounds like a winner for you, others may not agree. I can tell the difference between my iPod Classic (or iP4S) and my Benchmark and Onkyo DACs in A/B testing. It's evident around the edges of certain tones and their textures. It's like running your fingers along a beautifully smooth surface and feeling tiny imperfections. Would it be noticeable with Slayer? No, probably not. Tracy Chapman? Yeah.

That's not to say the Classic isn't good, I use mine a lot, but it has limitations.