Black Lion Microclock

[theblue1]

Originally Posted by Snatchman

You are right of course. But this is what I mean "The ears are the best test equipment". Your ears, his ears, her ears. Everybody ears will hear different. If everyone ears heard exactly alike as test equipment does, basically all mixes would sound alike. Everyone would pick the same equipment ( if you could afford it) etc. And I guess everybody would have the same...... clock!.... ..( YMMV)

Not only that... but you will hear differently tomorrow from how you heard the same thing yesterday. Your ears are very dynamic systems. A number of fluids and very small organs in complex systems... sometimes just swallowing can change how you hear something.

And, though most studios try to carefully control for variance in the monitoring environment, even in a treated room, moving the listening point by as little as 6 or 8 inches can have very significant effect on the perceived sound.

Simple DIY testing can show you these differences in your own environment -- in your own sweetspot... you don't need fancy calibrated gear to quickly demonstrate to yourself how moving the mic [analogous to your head/ears, of course] just a few inches can fairly drastically change the frequency reception in certain frequency bands -- even in what you probably think of as your sweetspot. (Now you will probably need proper test gear to properly tune your room but that is for another thread.)


Your ears are your most important test equipment (something I've been saying for years)... but an artisan understands his tools and their limitations. And that's why we have the kind of test gear that can produce consistent, reliable measurements to assist us in contextualizing what our ears are telling us today, at this listening.


[With the clock thing, I think it's important to understand the very strict limits to what I'm saying: I'm merely talking about about measurable phenomena that come from the basic facts of AD clocking and the effects of synchronizing to external clock sources. I'm not suggesting in any way that there is anything inherently wrong with any of the clock sources. Synching multiple ADs is, of course, necessary and, while one probably tends to get the most jitter-free sync with a properly terminated daisy chain slaved to the first AD in the chain, it may well be more convenient or preferable in some circumstances to use an external source in a star-topology. And, finally, I'm definitely not weighing in on whether clocksource X is better than clocksource Y.]

[emkay]

"If you've never compared a BLA modded piece to a comparably priced unit, how are you qualified to dismiss the BLA mod as crap on a stick? "


_______________________________________________________

I agree, one is NOT qualified to dismiss nor opine---But isn't that the kind of baseless, opinionated perspective that we are accustomed to and expect here at GS?

[peeder]

OK everyone who wants insight into this matter should go read this first. Then come back quite a bit better informed.

Next, do the following test. Go to Sonalksis - Quality Digital Audio Software and get their free FreeG thing so you can crank gain easily. This will help you hear the noisefloor of your converters easily. Set up DAC/ADC loops by just plugging a decent balanced analog cable from the analog out to the analog in of your converters, and send digital black in.

CAUTION: DO NOT send any signal in when you have the gain cranked, you'll FRY YOUR EARS. Turn down your monitors/cans to be sure. Headphones are better for listening to noise.

Sending digital black into the DAC, listen back to what comes out of the ADC. You won't hear anything until you crank the gain, which you can two with two FreeG's in tandem (turn the knobs up to +36db, and if you need more, push up the sliders). Now you can hear your converters' noise floor. (There may also be noisy preamps or something added to this loop on some interfaces...this is a way of testing that.)

Different converters will have different sounding noisefloors. Some will sound more pleasant or louder than others. Now switch from internal to external sync on the converter. For many converters, this will dramatically change the sound of the noise floor: you will often get a whining sound on external sync that is not present in internal sync. Note that even though the whining sound doesn't appear on an overall level meter, it is clearly audible, and if it is consistent for a given external clock, will add up and become even more audible if you record (and compress!) 24 tracks through it. You really don't want that whine with your cheese.

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.

So with external clocks you have the choice between decreasing the sound quality (as verified by harm buried in the noise floor) or having the same sound regardless. Worth paying more for? I guess you have to be the judge of that.

Now the digi paper suggests people may like the sound of jitter. There's more to the harm done by external sync than whines in the noisefloor and other anomalies. If you really like the effect added jitter gives, then let's look for bad clocks or just have someone make a clock with a jitter knob. (The jitter knob, of course, would be mounted so it just. didn't. reach. zero. =) 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.

Originally Posted by starfighter

WTF? This is absolute BS. Period. "to stay in the box where there is no clock" ???? Whaddya mean no clock? Free floating?

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. Once they get to the DAC there is a clock there, but they have the hardware buffer time to get there as soon or fast as they wish. If they go over the hardware buffer time, there will be a dropout or error or delay in the signal.

Period!

[thermos]

Never tried an external clock, huh?

Mine shipped. I'll report when I get it. I'll try to compare it to my friends Big Ben. I wanted an isochrone, but can't afford it. So well see.

Note, Peeder, anyone who invests the time and energy to try an external clock knows how to bypass their interfaces ability to override an external clock source.

[starfighter]

Originally Posted by peeder

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. Once they get to the DAC there is a clock there, but they have the hardware buffer time to get there as soon or fast as they wish. If they go over the hardware buffer time, there will be a dropout or error or delay in the signal.

Period!

So explain to me how realtime bouncing a 48 track mix ITB clocked to different external clocks sound different when A/B ing the 2 track mixes afterwards....

[theblue1]

I'm not sure what some of you guys are on about...

A converter's clock is what tells it when to "take" a sample of the amplitude as well as when to playback a given sample.

Processes that occur "in the box" (host computer) are not realtime processes, in the sense that they need not remain carefully timed.

If, for instance, you are bouncing tracks inside the computer (as opposed to mixing them together outside the box and bringing them back in) this is a process which is completely independent of your converters. They might as well be turned off.

When your AD converter sends audio data over a Firewire, USB, or PCI bus it is an asynchronous transmission -- unlike when we daisychain multiple converters and they must remain tightly synchronized for proper operation. Ditto for when your computer sends audio data back to the DA. (Firewire can be isochronous, as well, but the data streams are not synchronized, per se, AIUI.)

[peeder]

Originally Posted by starfighter

So explain to me how realtime bouncing a 48 track mix ITB clocked to different external clocks sound different when A/B ing the 2 track mixes afterwards....

Are there any ADC's involved? If there are no ADC's (analog to digital converters) involved, i.e. you have no channels open to them (be careful that you don't have any analog inputs enabled that you don't want!), then your bounces will be identical regardless of the clock of any DAC in use. Do them both, invert the polarity of one (aka "flip the phase"), and blend at unity gain (this is called "nulling" or "subtraction") to see if there is any actual difference in the bounce.

All this assumes of course that your system, converters, their clocks, etc. all works. There is some total crap out there (and in the 90's when many people's biases formed there was far more) that simply doesn't work and you might have to do things to work around that fact.

[starfighter]

Originally Posted by peeder

Are there any ADC's involved? If there are no ADC's (analog to digital converters) involved, i.e. you have no channels open to them (be careful that you don't have any analog inputs enabled that you don't want!), then your bounces will be identical regardless of the clock of any DAC in use. Do them both, invert the polarity of one (aka "flip the phase"), and blend at unity gain (this is called "nulling" or "subtraction") to see if there is any actual difference in the bounce.
n Fuumes of course that your system, converters, their clocks, etc. all works. There is some total crap out there (and in the 90's when many people's biases formed there was far more) that simply doesn't work and you might have to do things to work around that fact.

No ADCs; just realtime bounce down to 2 track.... Had my whole setup synced from a 01v96, focusrite octopre, creamware pulsar II and Universal Audio 2192... But what you're saying is that there's no need for sync ITB? It's all just random? I know the mixes null out, but naive little me thought the distance between samples (jitter) also had an impact on the way things sounded... Now I know why the drums are never in time...

[peeder]

It's not random, it's just not done in realtime until a converter is involved. Much more relaxing in there that way.

And yes, the distance between samples does matter, just only when a converter is involved! Internally, it's just a big list, and if you're reading down a list, you don't mind gaps so much. But if you're painting dashes on a road, and you change paint cans while the truck is still moving, then sure, there'll be a gap in the dashes that could cause problems.

[thermos]

Initial gut reaction: Very good. I'm going to do more extensive testing.

[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

[Brad McGowan]

Thanks Matt for stepping in and clarifying some of these issues. There's a lot of misinformation spewn forth on the internet by some. To those of us who don't have the proper background, it's often difficult to make sense of it all. I'm looking forward to reading your paper when it's done, so please keep us posted.

Even though I own a Mytek converter (with a great clock), I'm really curious to hear the BLA clock at some point.

I still don't understand how someone can go on and on about how external wordclocks make no difference when they haven't even spent the 5 minutes to hook one up and do their own listening tests. I guess that would make them look like even more of an ass.

Brad

[Gear Tramp]

Originally Posted by 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.

thumbsup I told him the same thing a while ago in another BLA thread.

Keep up the great work. Those of us that trust our ears enough to mix, also trust our ears enough to know when an improvement in audio fidelity has been made.

I still don't understand how someone can go on and on about how external wordclocks make no difference when they haven't even spent the 5 minutes to hook one up and do their own listening tests. I guess that would make them look like even more of an ass.

some people think too much and it gets in the way of reality and what is really happening.

peeder is always right, at least that's what he will lead you to believe, even when he says that he's never used a vocal-tuning plugin because he only works with talent.

something tells me peeder is full of himself. i can't decide what he's more full of though: himself or shit.

gotta love the internet!

[Max]

Originally Posted by invinco

I still don't see how these claims are any more outlandish than Apogee's. The most startling example is too lengthy to repeat here but can be found at this site: Apogee Electronics: Products: BIG BEN under the heading <i>A Cure for the Jitters – Apogee’s new “C777” Clock</i>
Here they have explicitly stated, not just implied that "Big Ben is able to re-clock devices with excessive jitter and function as if it were the master clock."

This statement absolutely true and verifiable. You are confusing using Big Ben as a slave to re-clock incoming signal vs. as a master clock. This is the same confusion others seem to have on other threads. Apogee never claimed Big Ben as a master clock would lower the jitter of a converter being slaved to Big Ben. We clearly state that Big Ben used as a slave can remove INCOMING jitter from a jittery clock source. Big Difference.

As for Big Ben improving the performance of other converters, it has nothing to do with less jitter and everything to do with AUDIBLE jitter. A signal induced with lots of jitter can sound audibly more ACCURATE to the ear than a signal with less jitter. The distortion on the signal with more jitter can be relegated to frequencies that are entirely out of the human audible spectrum, whereas the distortion on the signal with far less jitter can be at frequencies that are much more audibly apparent. For this reason one cannot say that an internal clock will always be audibly more accurate, merely that it will theoretically always have less jitter.

But is a specious faux-technical marketing blurb less reprehensible than a subjective collage of aesthetic buzz-words? In any case, Apogee has both bases covered. The key difference is that they can pay spokespersons to deliver the non-technical side of the spiel. In the sidebar you'll find all the comments about "clarity", "coherency" and "dimensionality" you could ever want.

Apogee does not pay for the endorsement of our products. Any and all quotes on our website or in our marketing materials are in the exact words of the end-users themselves. To purchase or fabricate these endorsements would severely compromise Apogee's credibility, something we take very seriously. Of course, our competitiors - whom many of you admit to being "sypathetic" towards - would love for you to think that we are this huge company with a huge marketing department full of $$$ to throw around. It's just not true. We try and make great products that get great results and give the people who use them a vehicle to tell the world. Good marketing? Yes. Dishonest? No.

[puff]

As for Big Ben improving the performance of other converters, it has nothing to do with less jitter and everything to do with AUDIBLE jitter. A signal induced with lots of jitter can sound audibly more ACCURATE to the ear than a signal with less jitter. The distortion on the signal with more jitter can be relegated to frequencies that are entirely out of the human audible spectrum, whereas the distortion on the signal with far less jitter can be at frequencies that are much more audibly apparent. For this reason one cannot say that an internal clock will always be audibly more accurate, merely that it will theoretically always have less jitter.

YES! Thank you, Max! IMO, it has to do with the type of jitter (whether random or deterministic), and the frequency band it occupies. I think that an amplitude-based jitter of certain harmonics (such as the excitation of a harmonic) within the clock signal can actually have a pleasing impact on the sonic characteristic of the sound if it's done correctly.

Matt
Black Lion Audio

[norman_nomad]

I appreciate Matt coming out to do a little tech explanation... I know personally I'm more prone to get out my wallet when I have, at least, a proper explanation of how and why a product works.

At the price point I may even buy the BLA clock to experiment with my system.

I'd love to hear other converter designers weigh in on this subject. Some of the info here is totally new to me, and I'd like to hear other expert opinions.

From Matt's last statement, it seems the whole art is balancing accuracy and aesthetics - that introducing certain imperfections into the process may result in a sound which is more "pleasing" to listen to.

Certainly this counterintuitive phenomenon is one source of general confusion surrounding the topic of external clocking.

[peeder]

Not sure bringing this thread back to life was so beneficial to you, Matt, but I appreciate your attention to my points.

Here's a long debate thread on the topic, from a couple years ago. It would be nice if we got Dan Lavry and Bob Katz in this thread to present their side of the story, but they probably don't want to get into it again. I think everyone should read it to get another set of expert views (even though it was prematurely closed down by someone else who makes money selling these things).

Will your paper be peer-reviewed and published in an accredited journal, Matt? While the art side of this is subjective, the science is objective, and surely any effects claimed can be demonstrated, quantified, and reproduced independently. So far, the Digi whitepaper is the only thing that I've read that has displayed reproducible data on the subject, everybody else is talking about their ears and things we can't see for ourselves.

I'm not an expert on this subject, but I am very interested in it, because just like fancy cables (something Apogee also sells) it smacks of the hi-fi BS that every professional should be well above. Asking me to pay you money (unrefundable, in the case of hardware modifications) to discover whether your claims have merit is not acceptable to me. Provoking the responses of experts (or at least, those trying to make a buck off this) I think actually makes me look smart, because I'm getting my questions answered before I lose dough. I couldn't care less about your business or my online reputation; I'm here to discover what the best way to make music is without wasting money. Your cooperation is appreciated.

I look forward to reading and critiquing your paper, and would appreciate citations to peer-reviewed research into this topic, ideally conducted by people who don't have a financial conflict of interest in the results.

[Gear Tramp]

Originally Posted by peeder

Not sure bringing this thread back to life was so beneficial to you, Matt, but I appreciate your attention to my points.

You're still blasting him and yet patronizing him for giving you attention!? Why?

I'm not an expert on this subject

Obviously. yet, you claim to know more than Matt, and your reasoning is simply that he's selling something and that people selling something have reason to mislead the consumer.

This isn't Behringer we're dealing with, it's a small company that WOULD GO UNDER IF THEIR WORK WASNT GREAT.

Not everyone in business is crooked.

P.S. With all the time you spend reading papers and such, do you ever actually recording any music and learning how these things sound in real-life applications rather than on paper? I hope you could post something in the mp3 section?

[puff]

Keep up the great work. Those of us that trust our ears enough to mix, also trust our ears enough to know when an improvement in audio fidelity has been made.

Thank you, Gear Tramp. I appreciate the kind words.

I'd love to hear other converter designers weigh in on this subject. Some of the info here is totally new to me, and I'd like to hear other expert opinions.

I'm sure we'd end up in a giant argument somewhere. Gear designers often have differing opinions on the same subject--it's like asking three different bakers how to make the best pumpkin pie. You'll get three different answers.

I have a friend who is a former EE professor from UC Berkley. He spends his time doing design work for Harman Kardon. He knows enough to make my head spin when it comes to analog design, yet I disagree with him on many points. Why? Because I have certain practices that, to my ears, sound better than certain popular textbook approaches.

I have three colleagues who helped me immensely with the Micro Clock's design: one is a prominent engineer who works for Philips, and was instrumental in designing the first CD player. One is an engineer who works for a particular aerospace firm and specializes in designing ultra-low jitter clocks. The third is a design engineer for a large pro audio company. Needless to say, there were times when one colleague would advise that I take a certain approach, and another would give me totally contradictory information. I ended up taking the route that, to my ears, gave the most sonically pleasing results.

Matt
Black Lion Audio

[Gear Tramp]

EARS vs. PAPER

Which produces the best music?

If you could choose between NO PAPER or NO EARS, and make a great sounding record using ONLY one or the other, what would provide the best results?

Peeder, it's like refusing to buy canvas unless you know the canvas will last 500 years. If you don't paint the canvas will always be blank and you can debate with 1000 "experts" about what kind of canvas is the best. And while you're arguing, someone will invent another canvas, and you can start the debate all over again. Meanwhile, the canvas remains blank, and the points go unproven.

"There's more to life than this"

[puff]

Not sure bringing this thread back to life was so beneficial to you, Matt, but I appreciate your attention to my points.

Don't flatter yourself. You don't have any 'points.' Just a bunch of regurgitated babble. You can't refute any of the arguments Max and I have made, you simply want to be stubborn about it.

The PSW thread--isn't this the same PSW thread that claims that 'fundamental crystals have less jitter than third overtone crystals?' That's completely false. It's the other way around.

I don't agree with that thread's overall assessment. I think there is MUCH more to the subject than is presented there.

Matt
Black Lion Audio

[peeder]

Well one result that could come out of studying this phenomenon is that it's all (or mostly) about the converter's PLL, and (some? many?) converters will have the same performance on any external clock. In which case, you could get the same effect with the $100 Hosa word clock box as the $1300 Apogee. Or just use the clock out of your old digital reverb.

Or that any beneficial effect would be even better with a combination you might think was worse when you looked at it. I.e. clocking your fancy converter to your cheapo would sound better overall. Etc.

We can study an audio signal, we can show skews in frequency distribution, in harmonic (and non-) distortion, in the noise floor and its frequency distribution, in impulse response, etc. We can contrast those results with subjective studies, done properly double-blind with enough of a sample size to reject the null hypothesis, and come up with observations such as "people like certain distributions of harmonic distortion." Then we can take the equipment in question and characterize its performance in those areas, precisely. We can at the very least use nulling/subtraction to determine if there is a difference in performance or not.

Surely everyone would like to spend the very minimum to get identical performance. If performance is not identical, in what ways, precisely, is it different, and are those ways significant enough, and beneficial enough, for us to justify the added expense? What is, in fact, the best way of configuring our systems?

Many people would like conversion to be as transparent as possible, and the argument certainly has been made that internal clock is the thing that does that. Generation tests over a series of DAC/ADC loopbacks should reveal that. The same goes for cables.

The most critical question is, why are the manufacturers coy about doing these quantifications and displaying the results? They at least probably have AudioPrecision gear that they are developing these things with, and I'd think they know full well what is happening and not. Care to share?

Anyone? Anyone? Bueller?

[drBill]

We had to have the BL clocks take OUT of some of a clients MOTU stuff due to WC issues. Not being able to lock up with other gear.

[norman_nomad]

Originally Posted by Gear Tramp

If you could choose between NO PAPER or NO EARS, and make a great sounding record using ONLY one or the other, what would provide the best results?

Who's making us choose?

I think most of us here are certainly capable of using both our brain and our ears.

I agree that in most all cases, the good mixing engineer is informed most by his/her ears. But there's nothing wrong with geeking out a little on the specs if just to better understand how those things we like to listen to actually work.

For me the verdict on external clocking is still out. However, I've only done one test with one set of converters and one external clock.

This new info, for me, may be the impetus for more personal experimentation which in turn may improve my mixes, or change my perspective/opinion. So there's a connection there.

I enjoy high level tech discussions, and when the 'audio scientists' out there can bring their work from the lab to the 'commoner' and explain it in such a way that it is generally palatable then I think they do us a great service as well as add credibility to their brand name.

Peeder is getting a lot of heat because of his tone, but I think some of his messaging is worth noting: Intelligent buyers of high-end products which are speced to perform an exacting task (such as clocks) require more than anecdotal evidence, they demand scientifically validated studies supported with non-biased peer review research.

If the data shows that the BLA box adds more jitter and distortion, but all the golden ears can agree it makes the converters sound "better" then we most hope that the savvy among us can live with this contradiction and still feel comfortable buying the product that sound better but specs worse. Because ultimately, as Matt points out, it's all about what is "most sonically pleasing".

[puff]

Well one result that could come out of studying this phenomenon is that it's all (or mostly) about the converter's PLL, and (some? many?) converters will have the same performance on any external clock. In which case, you could get the same effect with the $100 Hosa as the $1300 Apogee. Or just use the clock out of your old digital reverb.

From what I've noticed in my experiments, the clock signal's harmonic content has an effect on the converter's internal PLL response. Whether that means a converter's internal PLL sucks, I don't really care. Apogee, if I'm correct, uses a synthesized waveform for the C777 clock signal that's derived from two master clock sources, and because of this Apogee has greater control over what the initial content of the waveform is. That means they can sort of 'tailor make' a particular sonic response from a conversion process (to my ears, a Big Ben has a very big, smooth midrange similar to some vintage piece of gear).

The Hosa, I would wager, takes little to no precaution in preventing deterministic jitter from occuring in the division stage.

While deterministic jitter can certainly be added during signal injection into a given system, I found that it's not nearly as much deterministic jitter as is created during signal division. When I say 'deterministic jitter,' I'm referring to that content which gives a sonically undesirable result, such as high frequency harshness or loss of image. There are other types of 'deterministic jitter,' such as artificially boosting or exciting harmonics withing the clock's frequency spectrum that I feel shouldn't be necessarily counted if they give sonically pleasing results. Perhaps that falls in line with some of the ideas presented in Digi's white paper.

Listen to the sound that an external clock gives--each one is different because of differing spectral content. Then, manipulate that spectral content in some way by altering some element of transmission, and you'll alter the tonal character of the conversion process itself.

My opinion is that we want to keep the phase characteristics of the spectral content in question as pristine as possible. We also want to prevent unwanted harmonic elements from entering the signal.

But I also think we should have some fun with this--if we can get different sonic results by artificially manipulating harmonic amplitudes, let's play around with it. After all, experimentation is a good part of what music creation is about!

We had to have the BL clocks take OUT of some of a clients MOTU stuff due to WC issues. Not being able to lock up with other gear.

Yes--that's why we stopped doing the internal clock for MOTU. Variations within internal clock management caused problems with skew on some revisions.

Matt
Black Lion Audio

[peeder]

OK so why don't we take a couple of examples in detail then. A specific rev of a specific converter and a specific clock with a specific length of a specific cable. Have a few of these combinations in hand. All reproducible by any of us.

Let's develop a good test signal that has a combination of test tones...sines, squares, saws of both polarities, double sines (e.g. 17KHz and 19KHz), digital black, noise, impulses, phase interactions, and a variety of program material. Let's run it though each of these setups set both to internal clock and external clock via DAC/ADC loopback. Let's do several runs on each configuration, alternating in time to avoid e.g. thermal effects. Then let's take those signals and null them to the original signals sent in. Take a look with Audio Precision or Spectrafoo or whatever.

Is there a difference? What is it? What configuration is closest to the originals? What is furthest? What difference displays the lowest, most even noisefloor? What is the distribution of harmonic distortion, and how does it change at different frequencies?

Invite skeptics to contribute to the protocol. Maybe someone knows of particular test signals or program material that the converters have a hard time with, or that reveals differences best. We could use this protocol on everything and get a very good idea of what we're working with.

Give us something tangible. Where the rubber hits the road. You might convert me. If I'm $400 or $1300 or whatever from truly better audio, then you're not doing either of us a favor hiding proof of benefit. If you've got something you can point to that really works, I'll risk paying for the return shipping and the lost hours and buy the stuff and try to reproduce the test.

[Gear Tramp]

Originally Posted by norman_nomad

Who's making us choose?

I think most of us here are certainly capable of using both our brain and our ears.

I agree that in most all cases, the good mixing engineer is informed most by his/her ears. But there's nothing wrong with geeking out a little on the specs if just to better understand how those things we like to listen to actually work.

Exactly. But it is my firm belief that for the purpose of creating music, an individual should listen to one's ears 1st. The brain is still working when your ears are being used. This is not a literal, quantifiable experience. This is listening and will change at each and every moment. Once you have listened, exact your analytical powers to confirm or deny what you have heard and felt by geeking out.

[Gear Tramp]

Listening to music is the most important aspect of our jobs. It is what we do at all times. Every other choice is secondary to making the sounds we want to hear, whether we are the engineer, producer, or musician. Every gear decision is made (hopefully) in order to create the sound in our imagination, our mind, our abstract.

Here's a test of analytical understanding itself: Try to draw a schematic of your brain, so you will really know what it is you think you're understanding.

Creating the sounds you desire requires listening with your ears, not reading specs.

[andremattos]

Originally Posted by thermos

Initial gut reaction: Very good. I'm going to do more extensive testing.

any news? A/B ?

[deve]

Originally Posted by peeder

That's what jitter sounds like. Doubtless someone will chime in that the PLL in the B-word box is too lame to be externally clocked, but somehow, miraculously, other converters that need improved clocks have better PLLs than that and won't suffer increased jitter...

well, b-word box's clock is crystal... The Big b-word box has pll.