[puff]

Peeder, you've really crossed a line. Not only are your posts grossly misinformative, but they're insulting as well. I planned on leaving this thread alone, but it's gotten too far out of hand. It's clear that you know a small amount about digital audio, but not nearly enough to present information accurately, and you're far more interested in insulting me than anything else. What's especially odd is that you have NO first hand experience with our work. None. It makes you look foolish.

For your information, we've modified equipment for pretty much every major record label, prominent audio and film scoring engineers, and prominent film studios, not to mention drawing attention from several major equipment manufacturers.

Wow, we've really got people fooled, haven't we! Shame on us.

External clocks only help with synchronization issues with multiple otherwise independent devices. They do not improve the sound of converters, other than in very specific (and increasingly rare) circumstances. There are numerous reasons for the mythology of jitter that Bob Katz' book covers quite well. For nearly everyone with fewer than, say, four or five digital devices that must run simultaneously, a dedicated clock is a waste of money and has a better than even chance of decreasing sound quality.

I disagree. This argument completely ignores one of the most important aspects of word clock generation--the frequency division stage. In my opinion, this is THE biggest reason why an external word clock has the capability to improve upon conversion quality. In a poorly implemented modern system, with all clock management being performed within the FPGA, the divider will inject unwanted harmonic content into the clock signal. If one were to mux a superior externally generated WCK signal into the I2S component, sound quality will improve. I've read the argument about WCK's and accumulated jitter as they travel into a system, and I don't feel it holds any water. It forgets to take the elimination of inferior division into account. I'm working on a paper at the moment that shows exactly this--jitter within the WCK at the converter using a poorly implemented internal clock, and jitter within the WCK at the converter using a well-designed external clock.

The best way would be to measure jitter on a scope. That would make everything painfully clear.

No, a scope is not the preferred way to measure jitter. Not only are we looking for the presence of small timing variations within the wordclock waveform, we are looking for phase noise and unwanted spectral content. A scope won't tell us all of those things.

Now some better converters will re-clock the clock you send in and therefore there will be no difference. And therefore there is no difference. No difference! As in, it don't matter. Nope. No difference. So in those cases, well, there's no difference. Is this clear to you? I don't know how else to explain it.

All modern converter IC's have this capability on board, whether the circuit is good or bad. It depends upon which mode they are run in. And yes, in spite of your claims, there is indeed a difference--a WCK signal with one spectral content will give one result, a WCK with a different spectral content will give another result. I've experimented with it, and so has Apogee, and so has Lucid.

Nope, there is no clock ITB or digital to digital. There is more of a schedule of samples that all get processed in sequential order.

Not true. There is a clock signal when moving from digital to digital--word clock and bit clock. This is part of what digital audio is when it's digital--I2S. There is also a schedule of sample processing called LRCK or left right clock. It tells the converter which bits are most significant, and which bits are least significant. If we're moving information through spdif, AES, or some other ill-conceived transfer method, those components are muxed together and sent down a transmission line. But they're still there--they don't disappear into never-never land.

There's more to the harm done by external sync than whines in the noisefloor and other anomalies.

A 'whine' in the noisefloor isn't caused by jitter, it's caused by something else in the system. A whine is, in my experience, indicative of something improperly configured in the ADC circuit.

Different clocks going into different PLLs will have different sonic results, so this isn't about the clock per se. It's about the mix of clock and PLL and how it screws up the sound. You may, indeed, like a certain combination...I can't decide that for you. But you ought to describe the combination as a pairing of a given rev of a clock and a given rev of a converter on a given day...sometimes these things can vary based on phase of the signal or phase of the moon.

Wait, doesn't this negate everything you've just said?

Thermos, thank you for your kind words. I hope the Micro Clock serves you well.

Matt
Black Lion Audio