Quantcast
Will a word clock improve MY setup? - Page 2 - Gearspace.com
The No.1 Website for Pro Audio
Will a word clock improve MY setup?
Old 20th September 2012
  #31
Lives for gear
 
abechap024's Avatar
 
🎧 10 years
To the OP, that "mushy and loose bass" is a classic tale tail sign to me of cheap coupling capacitors. I have found that when replacing old or cheap capacitors in gear I would quantify the improved sound as a little more detail, less mushy and tighter bass.
Though inexpensive convertors can sound mushy (maybe grainy would be a better word for that imho) but just a thought. I would agree that until you break a certain price point clocking can only degrade performance. (in my testing I've found external clocking usually increases thd, though I have not done nearly as much testing as some gents in this regard)

Good luck with those new monitors!

Sent from my LG-VS700
Old 21st September 2012
  #32
Gear Head
 
🎧 5 years
Quote:
Originally Posted by theblue1 ➡️

Why do you think the S-o-S article is not to be trusted?
Simply because it is not a scientific test conducted with good guidelines under the guidance of an impartial group of professionals. And it is shortsighted. It's easy to say internal clocks are best. Generally they are and for the purposes of this thread that advice is good.

No big deal. It was aimed at selling magazines. Which it did. It barely scratched the surface of the issue. External clocking is not as cut and dry as most would like to think.
Old 21st September 2012
  #33
nms
Lives for gear
 
nms's Avatar
 
2 Reviews written
🎧 10 years
+1 on salesguy beatdown. An interface change is clearly needed. Those Saffires are far from clean. If you want any suggestions for interfaces though make sure you mention how many I/O and preamps you need. A Motu Ultralite mk3 and getting rid of your Rokits would be my advice for your price range. Replace them with KRK VXT6. MUCH better than the Rokits.

Just to clarify..

External clocking will not "melt your brain and take you away from music".

A superior external clock is better than clocking with an inferior internal clock. Please don't recycle hearsay guys.. it gets spread around sooo much with clocking.

Here's a basic RMAA measurement of an 828mk2 clocked internally vs externally. No fairy dust but also no measured degradation, THD, or extra noise here. A couple points variance in some of the columns happens from take to take so disregard that. I added a couple more units for comparison. With those units setup feeding from 2 separate DAWS and no clock sync between them there was significant clock drift (the test below isn't what you'd use to measure the improvements) when the 828mk2 was using its internal clock.
Attached Thumbnails
Will a word clock improve MY setup?-rmaa-clocks.gif  
Old 21st September 2012
  #34
Lives for gear
 
🎧 5 years
Try running a well known 'reference' track through your conversion chain/setup (like Uprising or Thriller or Who's Next, etc). Does the bass still sound mushy/loose?
Old 21st September 2012 | Show parent
  #35
Lives for gear
 
🎧 10 years
Quote:
Originally Posted by greenhirny ➡️
Simply because it is not a scientific test conducted with good guidelines under the guidance of an impartial group of professionals.
Oh really?

He documented the methodology of the test, would you like to point out which bit wasn't "scientific"?

The measurement and analysis was automatic, using high quality gear, and the only variable in each individual tests were whether or not an external clock was connected, and which clock it was.

The measurement itself was simple, and sound in signal terms, the spectrum of a sampled sine wave was examined, anything outside of the fundamental is by definition noise or distortion, and an indication of converter inaccuracy. In isolation one result doesn't tell you what the source of that inaccuracy is (johnson noise, jitter, quantization error), but if it goes up when you change something, then what you changed reduced converter accuracy.

True, he didn't test every possible combination of clock and converter, but he tested the big names in clocks, and a selection of converters, and they ALL came out worse, so it is reasonable to conclude that a situation where an external clock would improve a converter at the very least the exception, and not the rule many people claim it to be.

Also, it's worth noting that even in the worst case the degradation was very small, and unlikely to be perceptible in any real world situation, which really isn't all that suprising when we consider that converters should be designed to reject jitter levels which far exceed the differences you'd expect to see between clocks.

In fact if I was convinced that my converters sounded (rather than measured) different with an external clock (wether better or worse), I'd change converters rather than spending the money on a clock... the converter shouldn't be that sensitive, if it is then I wouldn't have confidence in the rest of the engineering either.
Old 21st September 2012
  #36
Lives for gear
 
aTelecine-Lex's Avatar
 
🎧 10 years
[QUOTE=abechap024;8275610]No[QUOTE]

Exactly...
Old 21st September 2012 | Show parent
  #37
Gear Guru
 
theblue1's Avatar
 
🎧 15 years
Quote:
Originally Posted by greenhirny ➡️
Simply because it is not a scientific test conducted with good guidelines under the guidance of an impartial group of professionals. And it is shortsighted. It's easy to say internal clocks are best. Generally they are and for the purposes of this thread that advice is good.

No big deal. It was aimed at selling magazines. Which it did. It barely scratched the surface of the issue. External clocking is not as cut and dry as most would like to think.
We're talking objective measurement here. We're not talking about ABX testing. They took measurements, they reported.

Now, I'm figuring if you won't accept that article as somewhat authoritative, that you probably won't accept Dan Lavry as authoritative, either, even though he's a veritable digital design legend. But here's some of what he has written about the issue...

He goes to some lengths trying to explain the issues from a number of angles, since he's clearly frustrated that people who he seems to believe have no understanding of digital audio are 'correcting him' on the basics of clocking.

This from the second quote below may serve as an abstract...

Quote:
When your AD is using the internal clock for conversion, you are doing the best you can. [...]

There are times when you need to use external clock, and when you need to, use external, when it is a needed trade off. For example, say you want to clock 2 or more AD chassis together... But other then that, internal is the better way to go!
https://gearspace.com/board/3648502-post74.html
Quote:
I saw some posters here that obviously did not bother to read what I said on TapeOP, yet chose to take an issue with it. What I said was not a bunch of opinions. I stated FACTS.

But I see that some of the defenders of the concept that external crock (I meant to say clock) improves sound are willing to accept the FACT that with very few exceptions, external clocking cause more jitter then internal. So the “new line of defense” is:

Maybe some jitter sounds better. After all, engineers are not musicians, and so what do they know…

Well, I am a musician and an engineer. So I will now comment mostly from a musical stand point:

There are many causes for jitter, but generally they fall into two categories: “random jitter” and “non random jitter”.

Random jitter increases the noise floor. It reduces the number of effective bits. Does anyone likes adding noise and working with fewer bits? I guess that settles the argument about random jitter.

So what about non random jitter? It introduces distortions.

There are a lot of folks that like certain types of distortions, such as the “warm tube sound” or a “transformer sound”. Those types of distortions are mostly due to FIXED non linearity in the “transfer curve”. Take a 1KH sound (fundamental and harmonics) and such distortion energy will alter the energy ONLY ON OCTAVES of the fundamental (2KHz, 3KHz, 4KHz…). That is not inherently un-musical, the sound is altered but the music is not altered (no addition of new notes).

But non random jitter does NOT do the same thing. The distortions due to non random jitter are not at all restricted to harmonic frequencies. On the contrary, they rarely fall on such harmonic locations. In fact, the distortion energy falls on all sorts of frequencies that have nothing to do with the music. The musical scale has 12 distinct frequencies (A, A sharp, B….). Yet the distortion energy of non random jitter will fall anywhere between notes, which musical speaking really sucks.

A musician (or a tuner) talks about the tuning of the modern musical scale in terms “cents”. There are 100 cents between any 2 adjacent notes. The idea of good tuning is to have the notes be within say 1-2 cents. A 50 cent deviation is terrible. A 20 cents deviation sounds real bad….

Say you have 120Hz jitter (such as jitter due to power many power supplies – twice the line AC source). Say we take a “standard” A440 note (440Hz). The jitter will cause energy to appear at the sum (440+120=560Hz) and at the difference (440-120=320HZ). But 560Hz is 17 cents above C sharp, and 320Hz is 28 cents above D sharp of a lower octave.

Let’s "play" the next higher note – A sharp (at 466.16Hz). With 120Hz jitter, the added energy falls on 96 cents above C sharp (4 cents below D), and also on 84.5 cents above E# of the lower octave.

Let’s try a 500Hz jitter source on A880 (880Hz). The outcome is energy at 78.5 cents above C sharp, and 45.5 cents above E at 2 octaves below…

Obviously, I have written a program that spits out the results of what jitter frequency does to any desired tone. I can go on, but I made my point: the non random jitter can not improve the sound, on the contrary, it messes things badly. And again, the other type jitter - random jitter can not improve sound – it is random, not connected to the music…

The distortions due to tubes, transformers, and other mostly analog gear are very different then the distortions due to jitter. One can argue that they like "coloration" due to tubes and alike, but coloration is a very "restricted" set of distortions - harmonic distortions. Jitter distortions are non harmonic. In fact I did not even bother to talk about other very "bad things" such as aliasing of jitter energy and much more. The very basics I presented is good enough to make my point.

Regards
Dan Lavry
And at some greater lenght (quoted here)...

Quote:
"Say you have a movie camera designed to take 100 picture frames per second, thus a frame every .01 second. You are pointing the camera at an ball moving from left to right at a constant speed, and you take a whole second of that motion, that is 100 picture frames. When you “play it back” with a movie projector that runs a picture each .01 second, everything would “be fine”, as intended.

But let us say that the camera is very “unsteady”. It takes a picture, then it waits .05 seconds, then it takes 5 frames within say .001sec, then a couple of frames at .01 second…. When you play it back, the projector “does not know” what happened at the camera, and the ball may like it is slowing at mid air for a brief time, then it zooms real fast some distance…. That is distortion due to timing error – time jitter. Note that if the camera was OK but the projector had jitter, that also would be a problem. So jitter counts at 2 places – at the camera (which is analogous to the AD), and at the projector (which is analogous to the DA). Jitter is important at the converters.

In one sense, jitter at the AD is more important, because once it takes place; it is in the signal forever. One can replace a bad DA with a good one, and that will eliminate the jitter issue of a poor DA, but what the AD does can not be undone.

Analogies can be misleading. In the case of movies, with enough still frames per second, the eye makes it looks like continues motion. In the case of conversion, it is the analog circuitry that takes the samples and makes them into a continues wave. But I chose the analogy of video, because audio and video (as well as many other applications) are fundamentally based on equal and precise time intervals. The time between each adjacent sample should be exactly the same, and if it is not, there is jitter, which will distort the outcome.

I said that jitter is important at the conversion. What about jitter in transferring say data from AD to a computer hard drive? The answer – it is not important, because we are just moving data from one place to another. You can move one frame every second, very slow indeed, or move a million frames a second, very fast. You can move half the data now, wait a while then move the rest of it… It does not matter, because you are not viewing it. But one you play it back you need the timing to be clocked precisely.
But some manufactures and sellers of clocks wanted to sell clocks, so they decided to convince the world that you need to clock everything. And with enough advertizing money, they where pretty successful doing just that. There are times when you need to use external clock box – when you want to have a lot of gear (AD channels) work together. But as long as you do not need external clock and you can use internal, use internal. It is not only cheaper, it is better!

What you need is the “best clock circuit you can make” that is very steady to be very near your AD circuit – short connection, good grounding… That is internal clock.

Say you take the same “best clock circuit you can make” and put it in another chassis. Will that be better? Not, it will be worse. You now have to deal with 2 chassis thus grounding issues. You have a cable that can pick interference, you have a cable termination imperfection, a cable driver, a cable receiver, and I did not even start… By the time your clock arrives from the clock box, it has so much jitter that it requires some “jitter cleaning circuitry” – typically a PLL circuit…. I pride myself for making very fine external clock circuitry, but no way can I make the external clock circuitry be as good as internal. Almost as good, yes, but never as good.

However, the clock BS’ers are still arguing that their external clock will improve the sound. There is some claim of a “proprietary clock signal” that will make things better. That is a crock if there ever was one! The clock box to the AD connection is a ONE WAY street. The clock “DOES NOT KNOW” what the AD is doing. What kind of a clock box signal is going to improve ALL the following an Ad's:

1. AD with a lot of jitter induce by 60Hz power line
2. AD with little jitter induced by 60Hz power line
3. AD with jitter induce from digital circuit noise
4. AD with jitter due to nearby radio transmitter
5. AD with jitter due to nearby power tools
6. AD with jitter induced from the digital audio data
7. AD with almost perfect timing
8. AD that is powered off…

This is analogous to a doctor that can cure all illness, doing so without any information about the patient…

One of the main offending marketing BS guys said that you can take a tone and have it sound better with jitter. You can alter a fixed tone with jitter, and can argue that you like it, or that you do not like it. But the alteration has to be deliberate for a specific constant tone (including fixed amplitude). You change the tone and the distortion changes... Jitter distortions are very complicated, and they are an INTERACTION between the clock timing AND THE MUSIC. The last I heard, music is not a constant fixed tone The simplest of jitter (random jitter) will increase your noise floor. More complex jitter makes for all sorts of undesired at frequencies that depend on the music, but at frequencies that are not musical harmonics, thus sound bad….

I first stated that internal clock is best a few years ago, and had to deal with a lot of attacks on a forum I was moderating. I insisted that the technical folks come in, instead of the marketing types, and sure enough, the technical types backed off after a short “fight” because they had no leg to stand on. A couple of years later, Digidesign wrote a paper about clocks, and they second me by saying that internal clocks are the best (when you can use internal clocks). I pointed that out and that brought about more attacks… The low jitter crock (I meant to say clock) goes on, and people are clocking with external clocks a lot of stuff they do not need to.

When your AD is using the internal clock for conversion, you are doing the best you can. The data sent forward to a computer, DAW or what not, is “after the conversion” so it does not need to be clocked with special care for jitter, and a “standard” link (say AES or SPDIF) is just fine for data transfer.

There are times when you need to use external clock, and when you need to, use external, when it is a needed trade off. For example, say you want to clock 2 or more AD chassis together... But other then that, internal is the better way to go!

Regards
Dan Lavry"
Old 21st September 2012 | Show parent
  #38
nms
Lives for gear
 
nms's Avatar
 
2 Reviews written
🎧 10 years
People get a bit careless though with misinterpreting Dan's comments. The context of them is in reference to the notion that anyone would ever take a high end converter such as his and go clocking it externally with one of those multithousand dollar clock units. Of course he & the guys at Antelope have strongly conflicting views there and it's one manufacturer vs another.

When we're talking about externally clocking a low-mid end unit it's a different story though.

Quote:
Originally Posted by Jon Hodgson ➡️
The measurement itself was simple, and sound in signal terms, the spectrum of a sampled sine wave was examined, anything outside of the fundamental is by definition noise or distortion, and an indication of converter inaccuracy.
That SOS test appears to be totally irrelevant.

I have tried to replicate those results in several configurations and never could.

The distortion measurements I just posted are indicative of that. There was absolutely no difference outside of the tiny variance you get from take to take:



I used 2 DAWS and my Hilo was the DAC. I also ran a 1min test file through which contains 60hz, 1khz, 10khz tones for additional exploring.
Old 21st September 2012 | Show parent
  #39
Gear Head
 
🎧 5 years
I completely accept Dan Lavry as an authority on the subject. Of Course I thoroughly reject hugh Robjons as an authority on the subject.


If you read my suggestions to the OP,

Quote:
Originally Posted by greenhirny ➡️
that is employing external clocking..I would highly suggest the OP stays with one interface that has a decent internal clock, which is most these days.

Clocking a multiple unit system is not as easy as 1,2,3 and will melt your brain and take you away from making music. Worry about that later. Your bass issue is more than likely your room, your speakers, your DA or any combination of all.

they are very consistent with what Mr Lavry has to say on the topic.


If you read NMS last post,

Quote:
Originally Posted by nms ➡️
Hey guys.. since we have a few regulars here..

That SOS test appears to me as completely fabricated bull****.

I have tried to replicate those results in several configurations and never could. If the errors weren't on purpose and supporting an agenda then they were by setup fault.

The distortion measurements I just posted are indicative of that. There was absolutely no difference outside of the tiny variance you get from take to take:


I used 2 DAWS and my Hilo was the DAC. I also ran a 1min test file through which contains 60hz, 1khz, 10khz tones for additional exploring.
it is very consistent with how I view SOS' complete abomination of info on the subject.

I have no idea who Blue 1 is, but at this point, based on the unnecessary length of his posts and inability to focus on the Op's request I would also have to reject him as an authority.
Old 21st September 2012 | Show parent
  #40
Lives for gear
 
🎧 10 years
Quote:
Originally Posted by nms ➡️
Hey guys.. since we have a few regulars here..

That SOS test appears to me as completely fabricated bull****.
Hugh posts on these forums, I haven't seen anything to indicate that he's anything but honest and consciencious in what he does.
Quote:
I have tried to replicate those results in several configurations and never could. If the errors weren't on purpose and supporting an agenda then they were by setup fault.
Have you used the same equipment? I think not because...
Quote:
The distortion measurements I just posted are indicative of that. There was absolutely no difference outside of the tiny variance you get from take to take:
RMAA is a loopback test which uses a sound card to generate the test signal as well as to capture it, your analogue signal by definition already has noise and distortion in it from the DAC process (with its noise, nonlinearities and jitter), and output buffers, Hugh was using test equipment that generated a high quality analogue sine wave which then went through one conversion process.

The test results in Hugh's tests indicated that the additional levels of noise were very small, and would therefore have been negligible if added to an already noisy signal, which is what you're working with. His tests show differences 140 dB down or more, yours show a residual noise level at -107dB or so, it's no surprise if your test results don't show any difference, the difference would be swamped by your (comparitively speaking) crappy source signal.
Quote:
I used 2 DAWS and my Hilo was the DAC. I also ran a 1min test file through which contains 60hz, 1khz, 10khz tones for additional exploring.
See above.
Old 21st September 2012 | Show parent
  #41
Gear Head
 
🎧 5 years
That's interesting. The last time I checked, we all listen through our DA.

Added noise is added noise. Does 1 + 1 now equal -140. I missed that math class. Was this new age math revealed in this month's issue of SOS?
Old 21st September 2012 | Show parent
  #42
Lives for gear
 
🎧 10 years
Quote:
Originally Posted by nms ➡️
People get a bit careless though with misinterpreting Dan's comments. The context of them is in reference to the notion that anyone would ever take a high end converter such as his and go clocking it externally with one of those multithousand dollar clock units. Of course he & the guys at Antelope have strongly conflicting views there and it's one manufacturer vs another.

When we're talking about externally clocking a low-mid end unit it's a different story though..
No, Dan has been quite clear on many occasions that he doesn't limit his thinking to high end converters like his, but rather expects it to be the norm for units to work better on internal clocks.

The thinking is this...

It's easier, and cheaper, to build a high quality internal clock than an equivalent quality phase locked loop to sync to an external clock, therefore the expected norm at any price level (and/or designer skill level) would be for a converter to have a better internal clock than phase locked loop.

It's perfectly logical, though is a little thrown by the fact that at least one converter has an architecture which passes all clocking, whether internal or external, through its phase locked loop... the Digi 192. I suspect that Dan would not approve of that design choice, it does seem rather odd I have to say.
Old 21st September 2012 | Show parent
  #43
Gear Head
 
🎧 5 years
Dan's expectations are solid, however, I'm sure there are many manufacturers that don't live up to his expectations.



I'm gonna guess the 192 does this because mostly the 192 was found in higher end rooms which facilitated serious multi tracking situations of 24 tracks or more at any one time.

Obviously as soon as you need more than one interface, then there is an external clocking situation in play, which would be always in the case of larger rooms.

Using a nice two channel converter as benchmark for all systems works for Dan's purposes, but hardly for the rest of us who are multi tracking more than 8 channels at a time.

Even though it is not popular to like digi/Avid products, they do tend to have good reasoning behind their designs and are popular in larger studios because they work like they are supposed to.
Old 21st September 2012 | Show parent
  #44
Lives for gear
 
🎧 10 years
Quote:
Originally Posted by greenhirny ➡️
That's interesting. The last time I checked, we all listen through our DA.
Yes, and your point is?
The point of the test was to examine the effects of an external clock on an A/D conversion, if you want to do that then you take a good clean test signal see what the conversion does to it.
You don't start with a signal that already has so much noise and distortion (from the DAC and output stages) that you can't see what's happening.
Quote:
Added noise is added noise. Does 1 + 1 now equal -140. I missed that math class. Was this new age math revealed in this month's issue of SOS?
What on earth are you talking about?
Old 21st September 2012 | Show parent
  #45
Gear Head
 
🎧 5 years
The point is to test external clocking effects on CONVERSION. A DA is a converter the last time I checked.

If you take a measurement of internal, then with external and there is ADDED noise or distortion, then it will be ADDED to the noise floor that already exists.

This is a measurement. Not a bowl of soup, where if you add small piece of carrot, it will sink to the bottom where you won't be able to see it.



Old 21st September 2012
  #46
nms
Lives for gear
 
nms's Avatar
 
2 Reviews written
🎧 10 years
Quote:
Originally Posted by Jon Hodgson ➡️
You don't start with a signal that already has so much noise and distortion (from the DAC and output stages) that you can't see what's happening.
Did you look at the specs for the Lynx Hilo in that same image I posted? You should take a look. 0.0004% THD and -119db noise floor for AD+DA. It's one of the cleanest converters in the world and more than suitable to test with.

Regardless, if the argument here is to avoid external clocking because someone claims noise presence below the noise floor of typical units.. what on earth are we discussing it for lol!

I can tell you right now that clock drift and jitter from using a poor clock will be a LOT more intrusive!
Old 21st September 2012 | Show parent
  #47
Lives for gear
 
🎧 10 years
Quote:
Originally Posted by greenhirny ➡️
The point is to test external clocking effects on CONVERSION. A DA is a converter the last time I checked.
You're trying to define the test as what you want it to be, not what it was. If Hugh wanted to test the D/A converter, then he would have done so, but that's a far harder job to do accurately, since you have to have two conversions.
However, since the clocking issues are the same for A/D conversion as for D/A, it is reasonable to extrapolate that if the ADCs function worse with an external converter, so will the DACs in those units (or the equivalent DAC an ADC only unit).
Quote:
If you take a measurement of internal, then with external and there is ADDED noise or distortion, then it will be ADDED to the noise floor that already exists.

This is a measurement. Not a bowl of soup, where if you add small piece of carrot, it will sink to the bottom where you won't be able to see it.
If your change is small compared to your residual noise, it can be hard, or even impossible to see.

It's hard to make a direct comparison, because we don't know how levels were set, and also we've got two different analyzers looking at the signals, however, let's say we have a signal with a noise floor which is -100dBFs, with -0dBFs being 1V

So the noise has an rms value of 10^(-100/20) = 0.00001

Now we put it through a process which itself adds noise at -140dBFs, this noise therefore has an rms value of 10^(-140/20) = 0.0000001

Now, the noise we would expect to be uncorrelated, which means that we don't just add those two values, rather we use the formula

nT = sqrt(n1^2 + n2^2)

So the rms of our combined noise is 0.0000100005

Which if we convert it to dBFs gives

20 x log(0.0000100005)= -99.9996dBFs

If you can taste that carrot you've got very good tastebuds.
Old 21st September 2012 | Show parent
  #48
Lives for gear
 
🎧 10 years
Quote:
Originally Posted by nms ➡️
Did you look at the specs for the Lynx Hilo in that same image I posted? You should take a look. 0.0004% THD and -119db noise floor for AD+DA. It's one of the cleanest converters in the world and more than suitable to test with.
I looked at your test results, your setup, for whatever reason, has noise levels that would swamp the sorts of differences shown in Hugh's tests. Therefore the two sets of results are not inconsistent with each other.
Quote:
Regardless, if the argument here is to avoid external clocking because someone claims noise presence below the noise floor of typical units.. what on earth are we discussing it for lol!
Because people regularly suggest to others that they should spend a couple of grand on an external clock which won't help them at all?

I would agree that people do get a bit caught up in the "external clocks make it worse" issue, yes they do in most cases, but in most cases by an insignificant amount. I would say, if you need the functionality of a dedicated clock unit (just having multiple units doesn't necessitate one, you can use one of them as a master), then spend your money and use one without worry, but if you don't, save your money and use it to do something which really will help, like buy better converters, or microphones, or to take a holiday.
Quote:
I can tell you right now that clock drift and jitter from using a poor clock will be a LOT more intrusive!
A lot more intrusive than what?
Old 21st September 2012 | Show parent
  #49
BOP
Gear Addict
 
🎧 5 years
Quote:
Originally Posted by Tui ➡️
You could do worse. I use HS50s for routine monitoring and when composing. I like them.
I use those too - they are decent.

Regarding the OP:

You din't mention what you are using to do the reference or what type of cans you have.

For instance if you are using a tune that you know well from listening on your consumer system then you are comparing a consumer system to a relatively flat system and possibly without having any experience with that tune being played back on well... a reference system for lack of a better word.

The deal is that usually bass response is not what you hear on the hyped up setups that most people use to listen to electronic music so you might have the wrong expectations regarding the whole thing.
If this is the case then a lot of things can help but nothing will cure the problem completely.

I would actually recommend you to first take your reference tracks and go to a serious studio that you trust. Not just any old place but one that will allow you to build up a reference in your head of how things should sound.

Then you can methodologically demo different products in order to get the best bang for the buck.

If you ask a salesman to give you something that will *insert adjective* then you will end up getting offered whatever would be the best sale for the shop.

Cheers,
BOP
Old 21st September 2012
  #50
nms
Lives for gear
 
nms's Avatar
 
2 Reviews written
🎧 10 years
Quote:
Originally Posted by Jon Hodgson ➡️
I looked at your test results, your setup, for whatever reason, has noise levels that would swamp the sorts of differences shown in Hugh's tests. Therefore the two sets of results are not inconsistent with each other.
I'll edit my accusation there, I didn't recall it was that far down. I thought he was implying it was something significant.

Quote:
Because people regularly suggest to others that they should spend a couple of grand on an external clock which won't help them at all?
Well if the only proven degradation is noise that's below the typical noise floors we encounter in gear, then how is that relevant to any of us and how could that even begin to weigh against the benefits of a good high end clock source vs your average onboard interface clock? When I looked at the audio for the internal clock recordings of that 828mk2 I saw all sorts of drift. Without any doubt the unit performs better when clocked externally.

To me anything happening below the noise floor isn't even worth discussing.

Quote:
buy better converters
I'm right there with you on that one! I'm a big supporter of buying a kick ass converter.. at least a 2CH ADC.. and using that as your master clock source. The Lavry AD10 is great there.
Old 21st September 2012 | Show parent
  #51
Lives for gear
 
🎧 10 years
Quote:
Originally Posted by nms ➡️
Well if the only proven degradation is noise that's below the typical noise floors we encounter in gear, then how is that relevant to any of us and how could that even begin to weigh against the benefits of a good high end clock source vs your average onboard interface clock? When I looked at the audio for the internal clock recordings of that 828mk2 I saw all sorts of drift. Without any doubt the unit performs better when clocked externally
Could you post examples of what you mean?

You appear to be describing something which is completely at odds with the test results you're publishing. Any "drift" in clocking of sample instances during the duration of a test large enough for you to see visually would be, mathematically speaking, SIGNIFICANT distortion, RMAA works using those same maths, so there's a total contradiction going on here.

Whether that contradiction is due to misunderstanding or bug I don't know, hence asking if I could see examples.
Old 21st September 2012
  #52
nms
Lives for gear
 
nms's Avatar
 
2 Reviews written
🎧 10 years
Quote:
"these tests that employing an external master clock cannot and will not improve the sound quality of a digital audio system. It might change it, and subjectively that change might be preferred, but it won’t change things for the better in any technical sense. A-D conversion performance will not improve: the best that can be hoped for is that the A-D conversion won’t become significantly degraded. In most cases, the technical performance will actually become worse, albeit only marginally so."
Man, reading that closing bit from the SOS article really makes me shake my head.
The human ear can NOT hear -130dbfs and in the real world none of us give a damn about it what happens down there. This still being added to the fact that I haven't been able to measure the slightest evidence of increase in my testing.


Here's what my graph looks like for internal vs external clocked. I blew it up big too. Not bad for an 828mk2 hey? MOTU 828mk2-int-vs-ext-clk.png

Which of the RMAA measurement figures do you figure should be affected by clock drift? I can't think of any. Can you find any evidence of Jitter on this old 828mk2 when on INT CLK?

I put external and internal recordings into one file and lined them up so you can check out the alignment at various intervals. Left is internal clock, Right is external.

2 DAWs used. Hilo was the DAC. 828mk2 was the ADC. For the EXT CLK recording I used a 1' long gotham spdif BNC cable.

RMAA Clocking test Motu828mk2_INT_CLK(L)_vs_EXT_CLK(R).wav

posting again for convenient reference:
Old 21st September 2012 | Show parent
  #53
Lives for gear
 
🎧 10 years
Quote:
Originally Posted by nms ➡️
Which of the RMAA measurement figures do you figure should be affected by clock drift? I can't think of any. Can you find any evidence of Jitter on this old 828mk2 when on INT CLK?
I think the first thing to establish is what you mean by "clock drift", hence asking for the examples. I can think of a couple of possibilities that you might interpret and describe as that, one wouldn't make any audible difference, the other would show up as distortion.

So I think we need to make sure we're on the same page.
Old 21st September 2012
  #54
nms
Lives for gear
 
nms's Avatar
 
2 Reviews written
🎧 10 years
It's clock drift. None of the columns listed above are things that would be affected by clock drift. Check the wav file at sample level in a wave editor. It's not just a clock running fast or slow but also drift back and forth over time.
Old 21st September 2012 | Show parent
  #55
Lives for gear
 
🎧 10 years
Quote:
Originally Posted by nms ➡️
It's clock drift. None of the columns listed above are things that would be affected by clock drift. Check the wav file at sample level in a wave editor. It's not just a clock running fast or slow but also drift back and forth over time.
Drift back and forth over time = distortion of waveform, that would show on the intermodulation distortion + noise reading.
Old 22nd September 2012 | Show parent
  #56
nms
Lives for gear
 
nms's Avatar
 
2 Reviews written
🎧 10 years
Quote:
Originally Posted by Jon Hodgson ➡️
Drift back and forth over time = distortion of waveform, that would show on the intermodulation distortion + noise reading.
Well as the measurements show us, you would clearly need a more significant/abrupt change to distort it in a way that could impact IMD or noise figures or it would be there. I did two takes each and there was no trend in one direction or the other outside of typical analog variance from one take to the next:

1. INT: 0.0020
2. INT: 0.0020

1. EXT: 0.0022
2. EXT: 0.0020
Old 22nd September 2012 | Show parent
  #57
Gear Head
 
🎧 5 years
nms I think it is pointless to argue with folks that think an SOS article has any resemblance to actual fact.

I and many others have already agreed that Dan Lavry's advice is great advice. We have also noted that in a lot of cases a lot of rigs end up with an external clocking situation and that is the reality of the situation.

It is my experience and many others that in CERTAIN cases an external clock HAS improved the sonics of a converter, but the problem with that is that that is a perception.


We all agree that staying on internal is a good rule of thumb. Some people will just find any reason to argue. Even when they are arguing with someone that agrees with everything except the part that their ideas are absolute. No one gets to be credited with absolute knowledge on anything. Even Dan Lavry and especially hugh robjons.
Old 22nd September 2012 | Show parent
  #58
nms
Lives for gear
 
nms's Avatar
 
2 Reviews written
🎧 10 years
Quote:
Originally Posted by greenhirny ➡️
We all agree that staying on internal is a good rule of thumb.
No.. we most certainly do not.

Did you actually read that SOS article? You have been saying it's BS but your statement above and advising against ext clocking is in complete agreement with the article. They say that using an internal clock is pointless and will degrade your sound causing noise. I have found this to be false in all testing I've done however including the one I just posted. There is no measure of additional distortion present at any level of relevance. There is absolutely nothing that should deter anyone from clocking your interface externally from a better clock source as found on Lavry, Hilo, Mytek, Prism. I'm with Dan Lavry though in that I would never bother externally clocking a high end converter.

The version that was clocked externally however receives the benefit of running off my Hilo's clock and does not suffer from clock drift. It gets better though..

I pulled up my own test file and checked out how the unit did on a 60hz tone. I compared EXT/INT clocked recordings at 44khz and 88khz and here's what I found:

The 180hz harmonic distortion was 4.7db better on the EXT clocked recording. This was unmistakable. I zoomed in maximum resolution and measured this carefully. However, when I checked the 88khz recordings they both measured the same hitting the figure that was 4.7db better.

This brings to mind what has often been said about cheaper clocks performing better at high sample rates.

Looking at the total sample length of this 55 second file, aside from back and forth drift in between, the internally clocked recording came back 66 samples longer than it should have. So my 828mk2 was actually running a clock speed of 88.198khz.

In comparing the 88khz takes the internally clocked take came back 129 samples longer. Divide by two and we have the same clock rate as found in the 44khz recordings.

I then extracted the 30 second song clip from the test file and used Audio Diffmaker to perform a null test with each of them against the original. A manual null test is no good here since you want to use Diffmaker's clock compensation feature to match the clock rates for a better alignment. Here's a measurement of the remaining residual:

INT CLOCK: -31.1dbfs
EXT CLOCK: -51.7dbfs

Obviously you can see a huge improvement in the externally clocked version. This is primarily due to the back and forth drift and pitch correction done by Diffmaker to correct the clock rate, but the rest would be external clock improvements.

So why bother clocking externally? Well, if you have a typical audio interface and you can't afford 8 channels of Lavry.. go pick up a high end 2CH unit with a clock output like the Lavry AD10 or the Mytek 192 DAC and you'll get kick ass conversion plus a nice master clock source. I think the Lavry ADC is better than the Mytek but the newer Mytek 192 DAC is fantastic and has clock out. Or if you have the cash go for the gold and pick up a Hilo.
Old 22nd September 2012 | Show parent
  #59
Lives for gear
 
foamboy's Avatar
 
🎧 10 years
HOLY COW!!!! you miss a couple of days and this thing turns into a science project!!!!


Anyhow,I really appreciate everybody's participation. This has turned into a much more enlightening thread than I could have ever imagined.

For those of you are asking me as to whether or not I have listend to various "good" recordings and noticed the mushy bass,all I can say is ... yes I have and no i don't. However,as others have mentioned, I have not listened on any other semi pro setups. Meaning, I have only been able to listen on my own speakers..studio monitors. I have listened to these reference recordings on hifi's for decades,but as we all know "monitors" do sound different and maybe I just really haven't truly learned my setup. Of course, I may still just get another set of monitors or really good headphones just to have a different
prosumer reference. I dunno.

Anyhow, I am going to continue to study,analyze,and troubleshoot and I'll keep everyone posted.

Thanks again,

fb
Old 22nd September 2012 | Show parent
  #60
Gear Addict
 
1 Review written
🎧 5 years
Quote:
Originally Posted by Nu-tra ➡️
Is your room treated?
Anytime somebody asks if they need to upgrade their gear, somebody always mentions acoustic treatment. Tells you something, doesn't it?
📝 Reply

Similar Threads

Thread / Thread Starter Replies / Views Last Post
replies: 109 views: 49223
Avatar for Den
Den 1st April 2013
replies: 8 views: 19726
Avatar for Anghello
Anghello 1st January 2012
replies: 59 views: 63971
Avatar for zajac1661
zajac1661 30th November 2011
replies: 419 views: 36751
Avatar for DanRand
DanRand 13th February 2016
Topic:
Post Reply

Welcome to the Gearspace Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.


 
 
Slide to join now Processing…

Forum Jump
Forum Jump