A couple of quarts of beer...

Discussion in 'Location Recording' started by Reverend Lucas, Dec 22, 2014.

  1. Reverend Lucas

    Reverend Lucas Active Member

    ... will not fix this so that it will not offend your ear.

    Donny shared his last show experience. I thought I'd share mine. Mine wasn't in a beautiful theatre, but in a local Irish pub that I've played every few months for the last sevenish years. The place has their own PA, and a Presonus 24.4.2. We normally run a 16.4.2 and send its Firewire feed to a laptop to record and mix down later, so I thought I'd attempt to to the same with the 24.4.2. I ended up having just enough time to check that the laptop was receiving signal, hit the record button, and hope for the best.

    When I went to playback what I heard was... well... it's below, but I'd be remiss if I didn't warn everyone of its contents. It's completely unsalvageable. There's a hideous crackling that's present on every channel.

    (Admin edit: fix wrong SC link! NOTE: just copy the link and SC will embed correctly)

    Any ideas on what would cause this? Signals were far from clipping at capture, and I haven't heard anything like this in capturing with our similar board. Capture was at 44.1 kHz, 24 bit, which is what I typically use.

    Apart from this, the show went well;)
  2. kmetal

    kmetal Kyle P. Gushue Well-Known Member

    That's weird, it almost sounds like vinyl, if you could tone it down it might actually be cool!

    What it's is im not sure, sounds like a bad connection, or clipping, maybe a sub group? Is it on all the indiviual tracks? It almost sounds like a mic clipping a bit too, kinda but not really. Dunno man, wish I could actually help.
  3. pcrecord

    pcrecord Don't you want the best recording like I do ? Well-Known Member

    Hi Lucas,
    It is very hard to tell where the crackles come without having the system to make some tests but here's my ideas on it:
    • A latency problem, or driver problem
    • Out of sync world clock
    • mismatch digital format
    • defective firewire port
    I could come up with more creative guess but those are the more logical ones.
    You need to reproduce the setup and verify all the settings.
  4. Reverend Lucas

    Reverend Lucas Active Member

    Thanks for the suggestions, gents. It is on every channel. I hadn't had any problems before, and hadn't changed any settings (44.1 kHz, 24-bit). This leads me to suspect that latency might be the culprit. We weren't actually recording any more channels, but I'm wondering if the added complexity of the board is affecting this.

    I don't have access to the 24.4.2 any more, but my next step is to play with the latency settings on the 16.4.2 to see if I can recreate it. In the mean time I can't trust the laptop.
    pcrecord likes this.
  5. DonnyThompson

    DonnyThompson Distinguished Member

    It's a great groove, very tight and a really cool feel... it's just too bad hat it's marred by this particular yet unknown gremlin.

    It is kinda cool as a lo-fi effect!

    But, I get that it's not supposed to be there.

    Boy, I dunno about this one, Rev. I'm kinda leaning towards PC's suggestion that it could be a driver or latency thing? It's not the stuttering that you'd find indicative of improper buffer settings, nor does it have the character of a bad cable, at least not any cable issue that I can decipher. And, you said that you weren't dealing with any mismatched SR or conversions ...
    I don't know enough about firewire to comment on that end.

    Have you made sure you are using the latest drivers and firmware updates? I know... stupid question, you probably already have...

    I've never worked with any external clocking, so someone who has and is more familiar with this process and its potential related issues would have to chime in.

    We need Bos. ;)
  6. Boswell

    Boswell Moderator Distinguished Member

    Thanks for the thought, but I don't think I can add very much here to the suggestions made already. Assuming the live PA sound through the 24.4.2 did not show any effect of this sort, and that its Firewire output port was not faulty, we are left with how it interacted with the laptop. It would be unusual that the sync was set wrongly at the FW input, especially if nothing had changed in the laptop since the previous usage with the 16.4.2, so we are left with the probability that some difference between the FW output of the 24-channel mixer and the 16-channel was causing buffer overflow in the laptop.

    This is maybe where DVDHawk could advise: is there for example a block size difference in the FW output stream between these two mixers?
  7. dvdhawk

    dvdhawk Well-Known Member

    I'm not aware of any known issues that would cause that sort of thing. But I am wondering if the house mixer was already running standalone at 48kHz, then you plugged in your computer running Capture at 44.1kHz - without a system reboot in the correct order to establish whose clock was in charge. If that were the case you would expect at least an error message asking you to choose, but I don't know. I'll be interested to see if you are able to recreate the problem.

    If the StudioLive is fully booted and running, the system will usually shudder (and lose audio) for a second when it senses the computer coming online. If this didn't happen, they never fully sync'ed.

    Details about the block size in the data stream are well beyond my pay-grade. Depending on the right Reverend's test results, PreSonus' tech support would be his most direct path to knowledge. If need be, I'd be happy to help.

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