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Is an external clock always better? Audio Interfaces
Old 29th July 2015
  #31
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Originally Posted by bad jitter View Post
So what is that company?
should be rather easy to figure out if you're good at context clues.
Old 31st July 2015
  #32
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Steve, I've not seen anything on the net claiming daisey chaining is a better practice than "T" connectors. If you have a source for that, post the link(s). Given you have a working arrangement you don't need to mess with it but if you have extra time and want to experiment, making your own wordclock cables and using "T" connectors is very inexpensive to try out. Like I've mentioned above I'm using multiple converter units (80 channels of conversion) and three RME 9652 PCI card computer interfaces clocked via wordclock cables and "T" connectors which gave me my best results with my experimentation (need that type of setup for use with an analog mixer).

Anyone want to chime in on whether distribution boxes have their wordclock out connectors wired like a house outlet (sharing the same source as what a "T" connector setup does), or if those wordclock out connectors have separate sources and/or isolation between the connectors using the same source?
Old 31st July 2015
  #33
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Quote:
Originally Posted by telegramsam View Post
I was just talking about this topic with a friend of mine, that uses the a BLA External clock. He seems to prefer his MOTU converters, when clocked to the BLA. I explained, what most folks in here have and sent him the SOS article.

Then he pointed me to this quote from BLA:

In the case of the Micro Clock mk2, there is very little undesirable in-band or out of band content (below 10 picoseconds using a Delta Sigma average). There is, however, an abundance of desirable harmonically related in-band spectral content; more so than the average internal clock. No PLL filter is designed to remove these desirable harmonics; they’re busy trying to remove the unwanted stuff.

I'm no expert, but BLA's explanation does not sit right with me.
Quote:
From Michal Of Mytek

Right on. External clock is in most cases just a distortion inducing device and many people seem to like this coloration and call it improvement.
..

the only thing I can think is, BLA must be saying they enhance the aspect which
they think is responsible for the distortion.
Old 1st August 2015
  #34
Quote:
Originally Posted by Bassmankr View Post
Steve, I've not seen anything on the net claiming daisey chaining is a better practice than "T" connectors. If you have a source for that, post the link(s). Given you have a working arrangement you don't need to mess with it but if you have extra time and want to experiment, making your own wordclock cables and using "T" connectors is very inexpensive to try out. Like I've mentioned above I'm using multiple converter units (80 channels of conversion) and three RME 9652 PCI card computer interfaces clocked via wordclock cables and "T" connectors which gave me my best results with my experimentation (need that type of setup for use with an analog mixer).

Anyone want to chime in on whether distribution boxes have their wordclock out connectors wired like a house outlet (sharing the same source as what a "T" connector setup does), or if those wordclock out connectors have separate sources and/or isolation between the connectors using the same source?
Hey Bassman, I'm pretty certain one such thing I read was actually a post in GearSlutz by a very knowledgeable user, it was a very long thread that lasted a couple of years. I don't have time this morning to search for it, maybe before the weekends over. But he talked about signal reflection as being the issue.
Other things I've read indicate that the use of a word clock distribution device was the best.

Not being an expert, and learning still - I wouldn't 'think' a few devices are going make much of a difference between daisy-chaining, using "T" connectors & a word clock distributor device. All I have are my several sound cards with word clock (I also have 8X8 midi routers & sound modules with word clock but I've never used word clock with those). I also have a Motu DTP (Digital time Piece).
Currently, I have (2) sound cards in one PC, and (1) sound card each in my other two PC's...In the future I may have 2 or 3 sound cards in each PC...I'll be adding a 4th PC at some point too. If I really do end up with this many sound cards & PC's, I may end up having problems.

I actually have bought a bunch of BNC "T" connectors, and BNC connectors to make my own cables & had planned to experiment between daisy-chaining vs "T" connections... then I read up on word clocking more, and it seems from what I was reading, that I may not be headed in the right direction. And have been considering a word clock distribution unit instead.

Another thought I had is, recently I picked up an 8X8 video Matrix distribution switcher & a 8X8 digital&analog Matrix distribution switcher... I've now been thinking about some kind of a Matrix switcher for word clock, since my method is never to use all PC's & sound cards all the time, but as they are needed...meaning that I'll only needing to clock 'certain' devices at 'certain' times as they're needed.

I'll look for what I read....
Old 2nd August 2015
  #35
Quote:
Originally Posted by Bassmankr View Post
Steve, I've not seen anything on the net claiming daisey chaining is a better practice than "T" connectors. If you have a source for that, post the link(s). Given you have a working arrangement you don't need to mess with it but if you have extra time and want to experiment, making your own wordclock cables and using "T" connectors is very inexpensive to try out. Like I've mentioned above I'm using multiple converter units (80 channels of conversion) and three RME 9652 PCI card computer interfaces clocked via wordclock cables and "T" connectors which gave me my best results with my experimentation (need that type of setup for use with an analog mixer).

Anyone want to chime in on whether distribution boxes have their wordclock out connectors wired like a house outlet (sharing the same source as what a "T" connector setup does), or if those wordclock out connectors have separate sources and/or isolation between the connectors using the same source?
Ok, there was a matter of days involved when I was reading quite a bit about word clock, and clocking in general with various methods...dedicated word clock & s/pdif clocking - which I've been using s/pdif successfully for a while now.
Of the many things I has been reading, were a post or so by a user named Francis Vaughan, which seems to know a great deal about clocking. He specifically talked about using "T" connections, and how it can reflect signals to degrade word clock. He also talks about how bad s/pdif is (which I use a lot), especially when running audio with clock data down the same cable simultaneously.

Here is that post below...

SPDIF vs. Word clock question

I'm not going to re-word what Vaughn say's as I'd likely screw it up. I skimmed through the above thread link quickly just to make sure this was the thread I was thinking of... it is. As I mentioned before, I read a lot in a short period of time some months ago, and I dod not specifically see where I thought I read that using "T" connections are worse than daisy-chaining...maybe it's in there, maybe I read it somewhere else , maybe I misunderstood something at that time (?).

Like you said, if having a system/set-up is already working well, maybe it doesn't matter. But it doesn't hurt to try to learn more. Experimenting is cool, but in my case, I often experiment blindly, being I'm not always fully knowledgeable going into things. But sometimes you can't wait until you know 'everything' before you begin to work with it, but learn as you go.

[EDIT]
WAIT, maybe this is what I was thinking about, just re-read some more from Vaughn...

Quote:
From a simple RF point of view T-Pieces are not good. Even though the ends are terminated correctly, the T-piece can never present a correct impedance. A T connected directly to the BNC connector on the back of the clock master is as good as you can get (never - ever - put a cable between a T and the point it is distributing from), and even this presents an easily measureable impedance glitch. How bad this turns out to be will depend on a host of other second order issues.

But daisy chaining assumes that the daisy chain repeater is not making a mess of things either. However it is possible to do a proper job of a repeater, whilst is isn't possible to do a proper job with a T. So, first cut is to daisy chain, unless you know the repeater is poor. This might be done as a first approximation of putting the better quality gear early in the chain - but that makes some assumptions too.

Last edited by Steve Fogal; 2nd August 2015 at 03:29 PM..
Old 2nd August 2015
  #36
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When using a single unit a/d, d/a, would replacing the internal clock with a better clock be possible?
Old 6th August 2015
  #37
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mrmike186, if you want to experiment with your single converter unit you would set it to external clock / Slave, and use some other clock feeding it clock signal via Wordclock/Madi/AES-EBU/ADAT/Spdif. That other clock feeding it would be set to internal clock / Master. Wordclock is clock signal only, the other digital formats I listed have the clock signal imbedded with it's audio signal.

Steve, most of the reports of Spdif being a bad digital format came from using too long of a copper wire Spdif cable, not from the optical Spdif option. If using copper wire Spdif you need to keep the length reasonably short.
Old 7th August 2015
  #38
Hi Bassman, I have been aware of keeping coaxial s/pdif cables at a reasonably short cable length. Mine are only 6ft long and labeled as digital s/pdif cables, all Hosa brand. I was not aware that (apparently) it was people trying to use overly long runs over copper wire, that gave s/pdif a bad rap. In my case, using coaxial s/pdif seems to work very well for me so far, but am exploring the use of dedicated Word Clock more that connection of a couple/few items.

And although "T" connectors are commonly used for word Clock, it seems that this is not the best practice due to the inherent signal reflection, and voltage division. The question is, how bad does it have to even be an issue (?) Or is it just that it often go's unnoticed (?).

I'm not claiming great knowledge, as I said I'm learning. And one thing I've been wondering about, that I've not heard talk of is, the use of both Word Clock AND s/pdif together...or more specifically on whether one uses the clocking of both.
Old 7th August 2015
  #39
Quote:
Originally Posted by mrmike186 View Post
When using a single unit a/d, d/a, would replacing the internal clock with a better clock be possible?
No, never better, as the internal clock is used to sync to the external clock. An external clock is only useful when multiple devices do not sync properly using t-splits or daisy chaining.
Old 8th August 2015
  #40
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What I meant was to replace the internal clock altogether. I noticed in the Ross Hogarth thread that he has clock preferences and mentions a black lion internal clock.https://www.gearslutz.com/board/q-ro...recording.html
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