Most of us know the importance of keeping our multiple digital devices synchronized when one digital output feeds another's digital input.

If you understand how digital devices communicate, it's easy to see the importance of setting a master clock source and making sure all the chained devices are using it. (That master clock could be from one of the audio devices or an external digital clock source, such as the Timepiece, Big Ben, etc.)


But I have, from time to time, seen people suggest that having a good external clock source can improve the fidelity of a single standalone converter (eg, say, a single MOTU 828).


I'm interested to see how my fellow Slutz will step up to that one.

True or false?


And, if your answer is true, I'd be interested in your reasoning...


cheers

Hi!
I use a Digi 192 I/O, and also own a Big Ben.

Does BB make the 192 "sound" better? IMO, no.
Does BB make the 192 sound different? IMO, yes.

I guess some will say the 192 sucks, others love it. I think it is a very capable tool, and short of building a room that is pristine, filling it with only the very top, pristine equipment, and finding I am paid so well as to villify the expense, I see no real reason to waste time for something else at this point. I did grab a Big Ben to be a master clock in what was going to be a multi computer setup (Gigastudio into PT), but plans change. So, I hooked it up to the 192, and tried the 192 via internal, and via BB.

I kept the BB in case plans change again, and to give me a choice.

I tried it with my old MOTU 2408mkII, and it sounded better (to my ears). But, I sold the MOTU, so I didnt need a clock for it after all...

That said: If I had the cash in my pocket today, and had expeirenced first-hand what I have, I would opt to buy something other than a clock. And if someone offered me about $50 under what I paid for it, the BB would be theirs heh

Short answer to your question: for some converters, yes- it can improve the sound. But, I would opt for a better converter first. And I cannot explain why right now, since my cat just bit me, and i am bleeding...ugh...

That's funny, one of my two young cats is MIA - he's never been outside this long, but I'll type my thoughts to keep me from worrying.

I'm about to find out tonight if I think an external clock can improve the sound quality of another converter. This isn't a new experiment for me, but the tools have changed this time. Previously, I was using Mytek 8X96's - first with an 888 (years ago), then an ADAT Bridge after the 888 was sonically eclipsed by the Myteks, and now finally with a Digi 192.

When using the Myteks as the master clock for any of the above, I would have to say the sound of the slaved units did improve. As you might expect - the 888 became far less brittle and 2D, and the 192 became rounder and fuller, with a smoother high end. Even the pair of DA in the ADAT Bridge were smoothed out by the Mytek clock.

The new tool is an Apogee AD16x, and it will be educational to find out for myself just what its clock (same as the BB) will do for the 192. My expectation is that it will improve the sound of the 192 marginally, and that the AD16x is a better converter which will be my next converter to yet again sonically eclipse a Digi product.

I'll know in a few hours! And hopefully my cat will be back by the time I come home from the studio.

I know how you feel about your cat. My cat is a rescue I took in a few years ago and when he's gotten out a few times in my new neighborhood, he's worried me crazy, despite the fact that, you know, he survived on his wits for years -- and the contents of some very dicey urban dumpsters in our old hood. Not nearly as many pits in this neighborhood, mind you, and whaddya know, the rich folks actually leash their dogs, but it didn't stop me from sweating him out pretty big. But cats are pretty good survivors. He's eventually shown back up. Although a few times he's decided to torment me by sleeping in an absent neighbor's (locked and fenced) sideyard where I can see him but am about two inches short of being able to grab him. I think that makes him feel somehow secure. The little sob.

I've got my fingers crossed for ya. That's such a scary feeling.

max

Well screw this converter talk for the time being!

My cat came back at around 10:30 last night! I was at the studio and got a voicemail to that affect. I had to excuse myself, go into the live room, and roar triumphantly while streaks of lightning bolted down from the skies and recharged my soul!! stike stike

I was told that his sister went out to look for him at around 10:00. If she found him, she must have told him something good... who knows what happened?! I'm just happy the little **** is back!

I checked him for any evidence of where he might have been. He smelled faintly of soil and earth, and the fur around his face was mildly dirty -- that was all I could discern about what he'd been up to.

Little bastard. I love him.

p.s. - thanks for empathizing!

I recently did a test with a client. We used a 192 and switched between internal and a Big Ben. The difference was unbelievable. It was so drastic I bought one the next day. I never imagined a clock would make such a difference. It sounded really bluury withouth the Big Ben. I never would have noticed until the comparison.

According to Dan Lavry, who knows a little about converters it is against the laws of physics for an external clock to improve the jitter of the internal crystal of any decently designed converter. So if you are hearing improvement while he will not tell you you do not hear what you think you hear he will tell you it is not because the jitter has been improved.

I Have a Midi time piece here and I did not feel any diffrence at all. But I am considering buyng an external clock master box. I use 2 digital boards ( 01v96 and 02R96V2) and a Mix PLus cubed hooked to 2 Adat bridges.
99% of time, 02R96 is master and 01V96 and PT interfaces are slave.

I think this is a load of hot hooey.

Just to frame this claim: a modern CPU or memory interface requires low-jitter clocking in the gigahertz range. And they get this low-jitter clocking day in and day out. I'm not talking about high-end computers: every computer. So, the claim is that while low-jitter GHz clock distribution is a consumer reality, it is extremely difficult to build a near audio-frequency clock (3 orders of magnitude slower) with sufficienly low jitter that sits similarly close to an A/D converter, and the solution is to put the clock across the room in a box that costs a lot.

Puhlease.

Surely somebody reliable has A/B'ed a high end converter w/ and w/o Big Ben and posted the result??

-synthoid

Right on!

I found myself checking back -- not to check on the thread but to find out about your cat! Of course, we all know that he, like all cats, will pull something like this again... but that's part of the joy of "owning" a cat.

My own cat (an alley-wise rescue from a tough part of town who nonetheless looks at first glance like some kind of Himalayan purebred) is so willful that I simply can't trust him on the ground anymore. But he's disconsolate when we don't go outside. So I freakin' carry him around like s stinkin' newborn! It's gotta be hilarious to my neighbors. A quick tour through the front 'yard' (a patch of concrete with a barbecue and a few lawn chairs) and back through the alley and he's usually more or less satisfied. But... well, I've adjusted.

I figure it takes a real tough guy to walk around the 'hood with a big white fluffy cat in his arms... Uh... it's all in the walk...

Back to the thread subject...

I started the thread because I was hearing a lot of things around the web that didn't necessarily comport with my idea of what external clocking is all about. I did some tech reading that fit with what I'd been thinking -- but there were so many claims floating around and so much conviction on all sides... I wondered if there wasn't something I was missing. So I thought I'd open a dialog and try to get a sense of what people thought and -- theory aside -- what they think they hear.

If there's ONE thing I've found in a decade and a half of digital recording -- it's that my assumptions aren't ALWAYS right. (A hard lesson to learn, of course. heh )

Case in point.


And yet we have a whole different take -- that fits with my technical reading, limited as it has been (where the line seems to be that external clocking can be useful for regulating synchronization between digital devices but is unnecessary with a single device).

And I think this post sums up the dilemna here, nicely:

Theory and experts seem to tell us one thing, marketers -- and the anecdotal experience of a number of users -- seems to suggest something else.


It's perplexing. But at this point I'm not entirely willing to write off a number of people who feel their ears are telling them one thing -- even if generally accepted theory suggests something different...

As I said, you hear what you hear. But the laws of physics don't lie. Read Lavry's White Paper on his site.

So if i.e. you hook a Big Ben to a single audio interface and it sounds better to your ears there are a few possibilities:

1. There is something severely wrong with the internal crystal of the audio interface. Unlikely these days.

2. On your system more jitter sounds better to you because of your taste, your monitoring system, or because it masks some of the deficiencies. Think of it as the difference between a pretty girl in makeup and without. She may look even prettier with the makeup but that is not truly what she looks like.

3. You are hearing what you expect to hear.

The one thing that is not possible is that there is less jitter unless item #1 is at work.

That's certainly consistent with my 'outside' reading. (And, by that, I mean white papers, explainers, etc, not necessarily the op-ed of my beloved GS brothers and sisters.)

I'm hoping we might find someone to take a contrary view and back it up with some facts/theory that might attempt to explain the perceived phenom in question...

Right now it seems like we're caught between the (not entirely consistent) anecdotal experiences of hands-on users who report a range of experience and what our "book learning" tells us should be happening...


I'm one who is inclined to lean on scientific fundamentals -- but I'll also be the first to say that there may well be aspects of the fundamental situation that have escaped me. And -- in the past -- I have on occasion been hoist on the petard of an incomplete understanding of certain fundamentals and the implications thereof...

So I'm hedging my bets and hoping to keep discussion open and rolling...

Dan's paper seems to imply that a converter will certainly not sound better or at least improve its clock spacing with an external clock

But does anyone use a converter this way?

I have adc's for the multitracks, soundcards with digital I/O's, a DAC for the 2 channel monitoring and digital I/O fx units

Putting on a clock I dont think I hear anything different in sound quality, but I certainly dont hear clicks, wheezes or any of the other weirdness that I hear when noone is sure who is boss. Probably would be just as well to have any one of the devices be master, but the clock has a bunch of outs and its handy to be able to throw the samplerate switch

Putting on a clock I dont think I hear anything different in sound quality, but I certainly dont hear clicks, wheezes or any of the other weirdness that I hear when noone is sure who is boss.

Of course, that is the function of an external wordclock, to lock different pieces of gear together.

Yes, people use them "the other way", i.e., to replace the internal clocking of an A/D converter when there is no other device in their system that accepts a wordclock input. And the question posed here is, does doing this sound better than using the internal clock of the converter.

-synthoid

I disagree.

I think a BigBen improves the sound of the Digi 192.

period.

YMMV

(I'll talk about the cat in another post and stick to the topic with this one. )

Having just (2 days ago counts) completed an unscientific word clock experiment with the AD16x as master and slave, I'd have to say that my expectations were largely met.

The test was unscientific in that there were no blind A/B or control groups, just a quick and dirty impression gathered by comparing what I'm used to hearing with what I just heard. If for you, this invalidates or demerits what follows, then don't bother reading the rest. I'll type about what I think of the AD16x 1st, followed by why I think there are any differences between the clocks of various converters and dedicated clocks.

My voice can be added to that of the happy campers who hear an improvement when using the AD16x's clock as the master to the 192. The difference to me was not unbelievably obvious and better, but a smallish yet significant enough improvement that if my setup required a master clock, I would buy and use the BB, or perhaps the Isochrone Antelope. I bought the AD16x to supply 16 channels of AD that I expected would be superior to those in the 192 (of which I have 8 channels), and to my ears, the AD16x wins.

Farming out the unoriginal adjectives to describe the difference:

AD16x is silky in the top, clearer and more focused in the midrange (this area is the most obviously different to me), tighter, more focused and not as sloppy as the 192 in the low end, and "more analog" (to quote my my guitar player); while the 192 is brittle ^up there^, sterile all around and papery. Still, the differences are not as huge as I expected or had read that they could be.

Oh yeah, I forgot to mention the source material, which I something I'm very accustomed to working with. My method of songwriting is improvisation (jamming) with a musical cohort who plays guitar or bass while I try coerce the truth out of the drums. We've done this for 4 years now, and the best parts of almost every session have been mixed by me and burned to CD. I'm so used to that sound that any minor difference between sessions is clearly audible to me. I never test unknown equipment on clients and I think it's risky practice for those who do.

Strangely, in another test where I didn't expect to hear any difference, the AD16x's clock seemed to also change to sound of well-mixed popular commercial material. The music of Beck (Sea Change), Ry Cooder (Chavez Ravine), Prince (Musicology), Massive Attack (Protection) and a few others were made to participate while the AD16x kept a watchful eye over the 192. Again, the silky top, tighter bottom and clear mids came to the fore. I expected no difference because I thought that jitter performance could not change when playing back digital source material - that only the AD stage is affected. Perhaps I have misunderstood what has been written on this area of the subject?

So.. given that the laws of physics are not defied by any external wordclock and that theoretically, there should be no measurable improvement in jitter performance for a slaved unit - yet there are myriads of posts hailing the BB clock as the best thing for digital audio since blackface ADATs were finally admitted into the Museum of Suckage - what is the middle ground of understanding?

I don't have the answer, but I have a theory: many (if not all) digital audio manufacturers are not 100% sure of what they're doing when they build a device with its own internal clock. They only build something that audibly tests better than that of their closest competitor, and market it as aggressively as they can behind the favorable words of the most popular audio engineer they can find. This is a very common model for the way scads of popular products come to flourish in most markets outside of the audio world. Why do we think it's any different for us??

Chew it.

many (if not all) digital audio manufacturers are not 100% sure of what they're doing when they build a device with its own internal clock.

... but they for some reason know exactly how to build a PLL that will lock tight as your skin to an external reference. Go figure.

-synthoid

Cynical, eh? It was just a theory, and I think you quoted it out of context. That's why the next sentence elaborated on the first, and was meant to show that I was talking about the intent of building a clock that is more pleasing to the ears than another. I have no questions about a manufacturer's ability to build things that perform a function "correctly" - but rather their reasons for doing so...

I think it's another example of technology doing something because it "can" and not necessarily because it "should" (except to take money from the hands of a competitor).

I never claimed as to why it sounded better, just that it did. Everything was clearer and much MUCH tighter sounding. I wasn't listening for a difference, it was an accident but we had to stop and see why there was such a drastic change. So I am happy to accept any explination. I am just happy with the sonic improvement.

originally by Asher
Hi:
I have been using an Apogee PSX100 for a while now, and one day, decided to try out the clock the PSX100. First I called Apogee, and the tech assured me that the clock in the PSX is very, very high quality, which means very good.
So I hooked up the clock of the Apogee to my 2 Delta 1010's, and absolutely, heard no improvements at all during playback, after hours of hooking and unhooking the devices together, on and off. The sound is not rounder, fuller and anything else like people have said.
While most people would qualify the sound as being better, they don't or can't quantify how, or in which aspect that it sounds better. And I am very disappointed that everytime people talk about clocks, they always qualify it as being better, but no one ever posted an mp3, before and after, even for 25 seconds, so that we all can hear how better it sounds with an external clock to prove the point. So at least I can learn for instance. So my question is: why even talk about it.
To me, better (especially in this forum) means more depth, more punch, sparkling at high ends, and big at the bottom as when you strap an Alan Smart C2 , or a RMS755, CraneSong ST8. SSL Xlogic to your mix buss.
If better means that everything is more tight, then all the clock actually does is to sync everything together well, which means that the timing has been repaired, if you have a timing problem. Of course, if the timing of the bass and the kick and the snare and etc... are synched together well, then your music should sound more together, yes better, but is more mathematic than qualitative. And Asher is right in saying that: if you do have that problem, then there is somehting awfully wrong with your converter(s) to start with.
So if somebody has a better quantitative explanation as to how an external clock can improve the sound, then I am all ears. No pun intended, just try to learn.
Sincerely.

>> hey always qualify it as being better, but no one ever posted an mp3, before and after, even for 25 seconds

Exactly. They exclaim: it's 10X better; no, 100X! Night and day. Every mouth in the room fell open!

And not even a crummy snippet of a sample to show us. These tests occur in a recording studio for crying out loud, rooms that are built to do nothing but record, and for some reason the recorders are never on when this breathtaking difference occurs.

Sheesh.

-synthoid

LOL!

Who told you this? Jitter in PC motherboards is vastly greater than that in today's DACs and ADCs, because good jitter performance on motherboards and CPUs isn't needed. It was largely the lousy jitter of early CD-era clocks (second only to antialiasing filter effects) in ADCs that caused those CDs to sound like crap. Distortion caused by jitter wasn't recognized by early THD measurements of digital music because the measuring equipment itself was corrupted by the same jitter. Julian Dunn's 1992 AES paper nicely describes how sampling jitter differs greatly in effect from transmission jitter:
http://www.nanophon.com/audio/jitter92.pdf
On pages 2-3 he provides calculations for jitter noise at given sampling frequencies. Jitter noise reaches 1 LSB of a 16-bit sample (-96dB) in a 20 kHz sinewave at 500 picoseconds p-p jitter. For typical clock rates of today's "delta-sigma" converters, which are typically 5 bits (actually PCM rather than delta sigma) sampled at 2.6MHz or 5.6 MHz, peak-to-peak jitter should be below 20 picoseconds. (Decimation is part the equation.) That's why the best clocks around guarantee 1 ps RMS jitter when new (the Mutec i-Clock claims...[ EDIT: I said 100 femtoseconds first; that's wrong, it was 0.1ppm accuracy, sorry synthoid and all, my error]), and why folks like Dan Lavry and Bob Katz insist on the importance of excellent jitter performance, which was until recently very expensive.
Regards, Sam

And speaking of Dan Lavry, I came across this nicely succinct summing up of his thinking on this issue in this thread at his PSW forum:

http://recforums.prosoundweb.com/ind...t/10086/15450/


I like Lavry's no-nonsense answers and cut-to-the-chase approach. His forum draws a bit more tech-savvy crowd than most of the recording oriented forums and BBs, which is refreshing.

Some of the threads there are really amusing -- as well as informative.

Recent faves included one on some injudicious pop science writing by Roger Nichols (wherein one poster allowed as how he had "great respect" for jet fighter pilots and their combat flying ability but he wouldn't necessarily go to them for a well-founded discourse on aerodynamic engineering) and an UTTERLY HILARIOUS riff on the website claims of a maker of super-duper-ultra-high-end interconnects (cable, eh? But when you charge 3 or 4 thousand bucks for a 4' foot hank of wire, you can't just call it a plain ol' cable).

Did you read the Dan Lavry explanation of why an external clock source can almost never improve the signal tracking of a single interface? (On contemporary pro devices.)

He never questions that people hear a difference.

He doesn't question whether or not they prefer the sound produced by an external clock.

What he is saying is that it is almost certainly less accurate than if the device was using its own internal clock.

It's certainly possible that people will like that more... but as Lavry points out, that difference is mostly attributable to increased jitter -- not less.

Lavry is pretty convincing.

I'm sure I don't have to point out that he designs some of most desirable -- and expensive -- AD and DA converters around. Not surprisingly, he's a university-trained electronic engineer who also unsurprisingly, appears to be entirely fluent in both analog and digital circuit design.

Now, I'm over-simplifying, for sure -- it's worth reading Lavry's own words. If you search around the Lavry site, you can probably find his white paper on clocking issues, which, as I recall, discusses a range of design considerations from both practical and theoretical views, and appears well-founded and properly cited. (Not the typical recording/audiophile marketing fantasy techno babble.)


Anyhow, I find this topic very interesting -- from a number of perspectives.

During a mix the producer asked me if I thought he should get a Big ben to improve the sound of his home studio. I told him my experiences and about the topic of this thread etc. I told him the only way to make such a decision was to try it. So I clocked his system to my bigBen and see if he prefered it or even heard a difference. He was so stunned by the improvement that he bought one that day. So maybe we're all imagining things, but as long as it's a drastic difference in our minds, we're all happy.