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wandering latency

Discussion in 'Recording' started by Southwind, Sep 17, 2001.

  1. Southwind

    Southwind Guest

    Howdy all,

    The program that I mainly use for multi-tracking, Cool Edit Pro, has a preference option that lets you program in an assigned latency for various soundcards you might use. Pretty cool, However,.....

    I have just spent a few hours trying to figure out exactly how much said latency is for each of the several cards and converters that I use.

    My test is this:

    1) Feed a click track (tock, tock, tock,....) out of the comp back into each converter and record.

    2) Zoom in and see how far off each "tock" is.

    Seems pretty simple to me, however the LATENCY CHANGES EVERY TIME I RECORD!!!!!!

    How can this be? I have managed to reduce the range of discrepency to about.05 ms. But still....

    What is driving the change in timing? The status of the CPU? Word clock? I have a Lucid A/D 24/96 that is serving as master clock for one of the cards....

    Any thoughts or opinions would be greatly appreciated?

    Charles
     
  2. Opus2000

    Opus2000 Well-Known Member

    well, I need more specifics before I can truly say...that is the problem!!...I need to know what cards you are using..what OS..Win98 or WinME..or Win2k for that matter..Cool Edit I know you use since you mentioned it..I havent used Cool Edit in several months(actually well over a year and change!) so I cant recall what the settings field looked like and how to change it..it sounds like some sync to audio program issues..when I see what card it is possibly it could be the drivers..let me know
    Opus
     
  3. Southwind

    Southwind Guest

    Thanks Opus,

    Sorry for the omissions. Here's the set up: two cards, three converters..

    My main converter is a Lucid A/D 24/96 which feeds s/pdif to an Echo Gina card (don't laugh please).
    I also, when needeed, use the Gina's analouge ins as well as the ins of a Darla 24.

    Now the Gina can be synched (word clock in) to the Lucid but there is no option to turn off the Darla's clock and synch it. So two clocks, three converters. I think that might be the issue.

    When the latency setting for the Lucid is adjusted, both the Lucid and Gina respond (makes sense, they're locked). The Darla is actually the one card whose latency seams to remain consistant. I can get it to track withing a sample on two (48k) of the original signal and it stays there when repeated.

    What is wierd is I can also get the other two inputs just as close. Then when repeated they wander. I adjust the settings, get them close again....and again two minutes later, they wander.

    I am running win98se. CEP lets you program latency for each assigned input in "options/device preferences"

    Thanks again,
    Charles
     
  4. Opus2000

    Opus2000 Well-Known Member

    I wont laugh since I use a Layla 20 bit card myself..I dont have any converters so I dont have to worry about that! I use all analog personally since I have a Mackie 1402 as my mixer..I'm a very small scale production..I dont need all the fancy gadgets out there.."yet"!!!
    Anyways...you have the Lucid running into both cards? is that what I am reading? If anything you should daisy chain the two echo cards together via word clock or SPDIF..this way the two cards can truly work as one with one generated clock signal..do you have the latest drivers for both your cards? Any programs running in the background when Windows starts up? type in MSCONFIG in your run menu and go to the startup tab and deselect everything but the System tray..restart and try it again..sometimes programs running in the background can impede your system performance.
    My other concern is that Cool Edit Pro may have some issue with the Echo driver. But I'm not so sure of that since the Darla works fine. Do you have ASIO 2.0 enabled? if so have you tried disabling it? Does Cool Edit Pro work with ASIO drivers? If not then that may be the issue...
    Tell me exactly how you have the clocking setup..SPDIF into Gina? then going to where..etc etc
    Opus
     
  5. Southwind

    Southwind Guest

    Thanks again Opus,

    Actually, the Lucid feeds the Gina SPDIF input. My Darla 24 doesn't have the option to lock to an external clock. Does yours?

    Basically, the Darla is on its own, I guess locking to CEP. The Gina is reading clock from the Lucid. What confuses me is that I figure it too is locking to the software...

    I am thinking that the problem is that there are two cards with two different clocks. Even though the Gina is acting as both an AD convereter and as a port for the Ludid, they are on one clock.

    How do you diasy chain cards as you described? Also, how can I figure out why the latency changes?

    Thanks again,
    Charles
     
  6. Opus2000

    Opus2000 Well-Known Member

    Well...Echo cards can sync together via the software program that comes with it..the Echo console..from there you can specify which card is master and which is slave...I only have one Echo card so I dont need to set a clock to it..besides it has word clock in and out plus SPDIF in and out...if you look at the PDF manual on the Echo site(which is currently down!!) it describes how multiple cards can be synced together via the software or clock..I have a feeling that your issues stem from that..A test to try is to remove the Darla card and see if you get latency drift still..make sure in the console setup that you set it to slave on internal/SPDIF or Word clock..also there should be a settings button where you can select Synchronize wave devices..set the sample rate to locked or unlocked and also set the digital to consumer or professional...I would look into the settings in your console..
    The console is a different install(at least for Win2k it is..I'm using that as my OS)try running it and play with the settings..see if it being set to consumer SPDIF instead of professional is the case as well..couple things to try..let me know
    Opus
     

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