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Word Clock??

Discussion in 'Pro Audio Equipment' started by jeronimo, Sep 25, 2001.

  1. jeronimo

    jeronimo Guest

    Hey guys, I was reading the post about the A/D converters and I saw you talking about how can you improve the audio quality if you have a good word clock source. Ok, here is my question. When you have a 001 for example and you use an ADI 8 Pro to record thru lightpipe, you use the ADI 8 Pro as the clock source right (on PT LE, Clock set to external)? Now, if I wanted to use a Gen6 to be the master what should I do? Set the ADI to receive WC and PT to clock to ADI? Now, if someone can explain me how do a better clock makes a better sound? :) sorry if the question is toooooo basic! :) )
     
  2. RandomGuest

    RandomGuest Guest

    Joined:
    Feb 10, 2001
    For that application you would need an external clock that did both WC for your ADI, and 'Superclock' for the P-T rig. This would put you in the realm of something like the Lucid SSG-192 or the Aardvark Aardsync. Unfortunately, at this time there isn't a clock that does both WC and Superclock that is under $1,000...there may be one released at AES this year, so I think I would recommend holding off on getting anything until you see what products are released at AES.

    Best of luck.
     
  3. sjoko

    sjoko Guest

    Jeronimo - look here for details on exactly what you want:
    http://www.lucidaudio.com/product_genx6-96_info.htm
     
  4. Hi Jeronimo,

    The master wordclock preferred by many PT users is Rosendahl's Nanosyncs. It provides 6 word clock outs, 3 of which can be configured as superclock, it also has an integral Black & Burst generator. The Nanosyncs is available from HHB and in the US costs about $1,000 - $1,100.

    In almost all cases a properly clocked digital system will virtually eliminate jitter and sound cleaner and richer than the same system without external clocking.

    One last point, if you use the Rosetta anywhere in your chain you have a problem. The Rosetta does not accept external word clock, so it has to be the word clock master.

    Greg
     
  5. td

    td Guest

    To contradict Fletcher ......... the 001 doesn't need Superclock, just regular old, run of the mill WC will do it, either by S/PDIF or Optical, no AES i/o is available. Which broadens your choices a bit.

    It doesn't matter what device is clocking your 001 ............ the input is what counts, Set the Digi to external & choose either S/PDIF or Opt for the source & you should right as rain.

    If you're using the 001's clock now, you'll see a definite bump in the quality of your sound.

    Tony
     
  6. sjoko

    sjoko Guest

    Greg, We've gone a bit further up the scale in an attempt to beat old mommy UK

    You can get a Lucid clock with a far lower jitter than the nannysync for around 500 bucks :roll:
     
  7. patrick

    patrick Guest

    Hey, Jeronimo. The answer to your main question, is yes, you would sync the ADI-8 to the Genx6 (or whatever) by wordclock, then you would sync your 001 to the ADI-8 through the audio input.

    But the next question is, why? OK, people say that the Lucid converters sound better than the ADI8-pro, and this is a judgement that anyone with ears, a decent setup, and the opportunity to compare, can make.

    But nobody has said anything about the clock on the ADI-8 being bad, and I haven't seen anyone testing the ADI-8 with a different clock. Even if somebody said it made things sound better with the ADI-8, well, I would guess that (unlike the sound quality of ad/da conversion) the stability of a digital clock is something that can be measured very precisely and scientifically, so, since the clock on the RME is certainly no dog at least, I would probably want to see some test results as well.

    Anyway, since you already have the ADI-8, and a fairly simple setup (i.e. you're not trying to sync a whole bunch of things at once), why not think about it this way? A Genx6 would cost you 500 bucks, and would probably give only marginal improvement at most, so--since you are also asking about cheap mic pres on another post--why not just put the 500 into a good mic pre, or three RNC's, or a Speck ASC, or something else that will give you much better sound going into your converters? For your situation, trying to build up your basic system with a limited budget, this would seem appropriate.

    just my suggestion, but 500 bucks is a lot of pizzas! :) :) :)
     
  8. homershines

    homershines Guest

    Has anybody used or have any feedback on the Friend-Chip Digi Tools units? There is a product similar to Lucid's new GenX6, on paper at least. It's pretty cheap, which may or may not be an issue.

    Also, could someone describe how one would hook
    up a small studio with a DAW, digital mixer and
    DAT, all with no word clock inputs to a master word clock?

    Thanks in advance.

    Homer
     
  9. sjoko

    sjoko Guest

    Patrick, with all due respect, the difference an external clock makes is far from marginal, it is very audible, and pretty major.
    If you would isolate the clock signal from the audio of "not-stand-alone" gear, it sounds like total discombobulation. Daisychain it from box to box and it gets progressively worse.
    There are many reasons for this, not the least of which are board layout and power supply.
    Clients in the studio here continue to be amazed when I demonstrate the difference by switching from external to generic clock, it is not a subtle difference, its an in-your-face huge one.

    Regarding investing in mics, pre's etc. before you'd invest in anything like a clock?
    I hold to opposite view. If you record digitally, get your system right to start with, and digital sound stands or falls by the quality of conversion and the accuracy of clocking.
    If your system sounds good, then further investment in your I/O chain starts to make sence, as only then will you be able to reap the benefits of high quality mics etc.
    In other words, if you have on of SP's mics and a nice Forssell pre, and use them on a system with bad converters and inaccurate clocking, they will sound like a recording made on a bad system, regardless of the investment.
     
  10. Originally posted by sjoko:
    Patrick, with all due respect, the difference an external clock makes is far from marginal, it is very audible, and pretty major.
    If you would isolate the clock signal from the audio of "not-stand-alone" gear, it sounds like total discombobulation. Daisychain it from box to box and it gets progressively worse.
    There are many reasons for this, not the least of which are board layout and power supply.
    Clients in the studio here continue to be amazed when I demonstrate the difference by switching from external to generic clock, it is not a subtle difference, its an in-your-face huge one.

    Regarding investing in mics, pre's etc. before you'd invest in anything like a clock?
    I hold to opposite view. If you record digitally, get your system right to start with, and digital sound stands or falls by the quality of conversion and the accuracy of clocking.
    If your system sounds good, then further investment in your I/O chain starts to make sence, as only then will you be able to reap the benefits of high quality mics etc.
    In other words, if you have on of SP's mics and a nice Forssell pre, and use them on a system with bad converters and inaccurate clocking, they will sound like a recording made on a bad system, regardless of the investment.


    Does an external WC device help the audio quality significantly when there are only two things 'talking' to each other? I have a DA7 and a MOTU 2408 interface with clock coming from the DA7. With such a basic setup, would I notice much difference,(providing I possessed the ears required to hear it)?

    Steve
     
  11. Hi sjoko,

    << We've gone a bit further up the scale in an attempt to beat old mommy UK. You can get a Lucid clock with a far lower jitter than the nannysync for around 500 bucks >>

    Yes, but it's not much use for PT TDM. Neither does it have an integral Black & Burst generator. BTW, in general forget jitter specs!!

    Greg
     
  12. patrick

    patrick Guest

    Hi sjoko.

    Yes, I have no doubt that the external clock helps your system. I have read and enjoyed your posts on converters etc, and am not arguing with you at all about anything you have said about your system and your experiences.

    I was not talking about systems in general, I was talking about the ADI-8, hooked up to only one other device slaving from it, as in Jeronimo's setup. (I gather the digi 001 is just a sound card with a breakout box). My comments about the ADI-8 referred to its clock (not to it's sound quality), and the extent to which it would benefit, in such a simple setup, from adding an external clock. I have not had the opportunity to test it, of course, but I do know that the RME people put a lot of emphasis on the quality of the clock in their publicity, and they have put up a bunch of test results on their web site. Maybe they're exaggerating, but on the other hand maybe, even if the sound quality of their converters might leave something to be desired, they are right about their clock? It's not meant to be a master clock for a larger system, since it only has one word clock output, but that doesn't mean that the clock itself is bad. I have yet to see anybody say that they tested the performance of the ADI-8, in basically a standalone operation (i.e. connected only to the sound card/breakout box), with an external clock. (I don't know if the digi 001 has a word clock input?)

    My advice was also specifically directed to Jeronimo, which should be very, very, very clear from my post. If you've read his other posts (which I also referred to), you should know by now that in his system, his converters and clock are the best part of it, even if they are not your own preferred brand. Sure, everyone needs decent converters and a clock for a digital system, but are you trying to say that the RME is absolute crap as a clock, and that he needs to get another clock to help it, instead of spending his limited resources on other stuff? Do you really think that his system will benefit more from an external clock, than from getting an $800 mic pre instead of a $300 one?

    I'm not an expert, just hanging around here trying to learn. Like him, I am trying to build up a system on a limited budget, so I am just trying to help him from being dazzled and confused by the all the options, and equipment, and enthusiastic recommendations, that are out there, not all of which are appropriate for every system, every time.

    My advice, which was directed only to him, still stands. Spend the money on something else. And anyway, like I said, it's only my suggestion to him, and he's free to do what he wants. Other people will have to judge what's best for their own systems.

    all the best, cheerfully yours,

    :)
     
  13. jeronimo

    jeronimo Guest

    Hello Patrick, I totally understand and agree with your point of view. The only thing I would like to do is test the ADI (that I don't have yet) with and without the external clock to hear the difference and then judge if I should spend the money or not. I'll try to look around and see if I can find a GENx6 somewhere :) !
     
  14. patrick

    patrick Guest

    Hi Jeronimo.

    Actually, I agree with both my point of view, and sjoko's point of view: when your system (and mine) gets big enough to benefit from a master clock, like his, do it. Until then, get the best converter with the most stable clock that you can afford.

    If you get a chance to test one out, please let us know.

    cheers,
     
  15. Hi Jeronimo,

    I'm sure you've probably got your head around it by now but for anyone out there that doesn't fully understand:

    Whenever you link audio equipment together digitally, the first piece of equipment in the chain generates a clock signal which defines the time duration of a digital word. In the case of CD the duration of the word is 1/44100th of a second. This word clock signal is embedded in the digital audio stream and is passed on to the next piece of equipment in the chain which uses it to reference it's own word duration. Although this works there is a problem. The second piece of equipment in the chain has to wait for the clock signal to arrive from the first unit, un-embed it and use it as a reference. This introduces a slight delay, called jitter, which adversely affects audio quality. As you add more pieces of equipment to your chain the system's total amount of jitter gets compounded.

    Ideally there are two problem areas that need to be addressed: Firstly you want an accurate, stable clock from the first unit in the chain. Otherwise you are going to distribute and add jitter to an already jittery clock. Secondly and far more importantly, you would want all the units in the chain to receive the clock signal at exactly the same instant, rather than having to wait for it to be processed and passed on by all the other units in the chain. The piece of equipment that allows you to solve both these problems is a masterclock. A masterclock not only provides an accurate, stable clock but also provides a number of word clock outputs. Each unit in your chain can now have it's own individual word clock signal that has not been delayed by previous units in the chain. Make no mistake about the importance of this last point. If you add up the jitter specs for all of the units in say a 3 or 4 unit chain the total figure will probably be around 40 - 80ps but you could be adding several hundred pico seconds of jitter by daisy-chaining the clock signal!

    One last point to bare in mind: Jitter specs aren't worth the paper they are printed on! Is that the jitter introduced by the internal clock, when referencing from an external word clock signal or when referencing from an embedded digital audio stream? At what point in the process has the jitter been measured? Has that figure been averaged or is it the peak? Over what duration has the jitter been measured? Each manufacturer does it differently, which makes comparison impossible and negates the whole point of publishing the specs.

    Jeronimo, in your case a masterclock is going to make very little difference. The Rosetta doesn't have an external clock input and therefore has to be daisy-chained from your ADI. So the only thing adding a masterclock to your setup is going to achieve is to replace the internal clock of your ADI and reduce your system's jitter by a few pico seconds. I doubt you will hear much difference unless you also have other units in your chain like a DAT or CD.

    Homer, if your equipment doesn't have word clock inputs you have no choice but to daisy-chain them. Adding a masterclock to your setup is only going to provide a fraction of the potential benefit. In your situation, the only other way you can minimise your system's jitter is to make sure that all the digital audio cabling is of high quality, the correct impedence and as short as possible. The moral of the story is to make sure that any digital equipment you buy for your audio chain has word clock inputs. Unfortunately it only tends to be the higher end, more expensive digital equipment that provides separate word clock inputs.

    Hope this helps,

    Greg
     
  16. sjoko

    sjoko Guest

    Of cause, as greg correctly stated, if you don't have a seperate clock input on a piece of gear, the clock for this gear will onlt be as good as the source that feeds it. It the "feeder" is a generic clock, the signal will be of a certain quality, If its a stand-alone, it will most likely be of a higher quality ..... which will also transmit higher quality down a chain.

    Is it worth the investment or not? Like always, the proof is in one thing - try it and use your ears. After all, thats the only thing that really counts.

    Greg, I don't want to disagree with you but, Quote:
    "Yes, but it's not much use for PT TDM. Neither does it have an integral Black & Burst generator. BTW, in general forget jitter specs!!"

    I find it brilliant for PT TDM and you don't need blackburst unless you're in post or video production?

    Regarding specs and jitter specs in particular;
    I'm involved extensively in testing of gear. In this I use my own methods and principles, not those of any manufacturer. My first principle is that I use my ears and fortunately I've been blessed with some good ones. If something does not sound good, specs don't matter a damn.
    Second, there is bench testing. ALWAYS testing involving a range of 'same' products ... exactly the same procedure for each and every piece of gear. The resulting specs are specs that do matter, real specs. After that the interesting thing is to do comparisons between the listening notes and graphs, to see where the problems might be.
    Just ment to say that, whenever I mention specs, I never mention manufacturers' ones, one those I know were done correctly.

    By the way - just as a point of interest,I listened to the Gorillaz CD last night. Without knowing how it was recorded, it sounds 100% like Pro Tools using its generic clock using digi's 888 converters. In other words flat , lifeless and bad. Pity.

    Love, peace and use your ears :)
     
  17. jeronimo

    jeronimo Guest

    Greg, thanks for sharing your knowledge with us all. I actually don't have any other converters but the 001. I'm planning to get or the ADI 8 to use with the 001 or say bye bye to PT and use Hammerfalls with ADI converters, I don't know yet. But thanks anyways!! Have anyone heard the Hammerfalls DSP with the Multiface interfaces? :)
     
  18. homershines

    homershines Guest

    Just a note:
    If anyone is interested, MacMidiMusic is selling the GenX6 for $329.00. http://www.macmidimusic.com
    And nope.....
    Don't work for them.

    Peace...for REAL!!!!


    Homer Jackson
     
  19. Hi sjoko,

    << Greg, I don't want to disagree with you but, Quote: "Yes, but it's not much use for PT TDM. Neither does it have an integral Black & Burst generator. BTW, in general forget jitter specs!!"

    I find it brilliant for PT TDM and you don't need blackburst unless you're in post or video production? >>

    The difficulty with my setup and many other TDM setups is that my interfaces need superclock and my mastering machines and a few other bits of kit need standard word clock. The GenX6 will not work in this type of setup as it's 6 outputs all have to be either standard word clock OR superclock. With my Nanosyncs, up to 3 of the 6 outputs can be configured for superclock whilst the remaining outs are providing standard word clock.

    BTW, although I generally use the B&B outputs to sync to picture, I also find them useful when adding a piece of analog gear to the chain and to provide a reference to my MTP/AV.

    Greg
     

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