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glitches in recording; faulty harddrive/RAM?

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glitches in recording; faulty harddrive/RAM?

Postby mjfe2 » Tue Feb 07, 2012 11:36 am

I've posted about this problem before (it's proving *very* difficult to pin down the cause of the problem!) but I thought I'd ask again. Basically, my Fireface is occasionally recording small digital glitches to my Macbook. It does it even when I'm recording a simple stereo arrangement and the buffer size is set to 512 samples, which is obviously ridiculous on a new MacBook Pro. I use Reaper, but it used to do it in Harrison Mixbus, and used to do it on my old Mackie Onyx firewire interface. It doesn't do it if I monitor in TotalMix so I know the problem is somewhere in the storage of data.

I've tried closing all other open programmes, turning off airport etc. but to no avail. I then thought, perhaps it's the internal harddrive that's faulty and not quite keeping up, so I've moved to recording to an external USB harddrive. However, it did the same thing on a live recording the other day (which is almost impossible to mend!). I want to check I'm doing this right: I have Reaper installed on my Mac HD, but I saved a new RRP file to the external harddrive so all files were recorded there instead. Is that the optimum way to record?

I took the Mac in once before because Techtool deluxe was showing up a 'volume structure' error but they tested it and said don't worry about that. However, even things like Youtube and, more recently, mp3s in iTunes (!) have been slightly glitching (i.e. a split second silence). Am I right in assuming that all this points to a faulty harddrive or RAM?
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Re: glitches in recording; faulty harddrive/RAM?

Postby Richie Royale » Tue Feb 07, 2012 12:16 pm

Most glitches I have had in my system have been down to drivers for the audio inteface. The RME is supposed to be "rock solid", so I would check the simple things first; is the FW cable in good condition, or have you tried a different one? Are the drivers up to date? And what OS are you using, are their any possible issues if for instance you are using Lion (just a guess).

It is recommended to record to a separate drive than the OS is installed on.
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Re: glitches in recording; faulty harddrive/RAM?

Postby mjfe2 » Tue Feb 07, 2012 12:22 pm

Most glitches I have had in my system have been down to drivers for the audio inteface. The RME is supposed to be "rock solid", so I would check the simple things first; is the FW cable in good condition, or have you tried a different one? Are the drivers up to date? And what OS are you using, are their any possible issues if for instance you are using Lion (just a guess).

It is recommended to record to a separate drive than the OS is installed on.

Drivers and firmware are definitely up to date (as they were on the old Mackie interface) and I haven't taken the risk with Lion yet! It's the Fireface UC, but the USB cable seems fine.

Re the separate drive, did I do it right? Or should the DAW be installed on a different drive to the OS as well?
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Re: glitches in recording; faulty harddrive/RAM?

Postby Richie Royale » Tue Feb 07, 2012 12:28 pm

The DAW stays on the OS drive in the applications. Just the recording target folder is recommended to be on a separate drive. I would perhaps try a differnt cable between the interface and computer, but these things can be frustrating. I presume you don't have Time Machine active?
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Re: glitches in recording; faulty harddrive/RAM?

Postby mjfe2 » Tue Feb 07, 2012 12:31 pm

Frustrating indeed! Time Machine is off. I might try a different USB cable, but as I said, the Mackie firewire interface had the same problem too. I haven't set my external hard drive as the *default* recording location, I just open new RRP projects on the HD when it's an important recording -- presumably that wouldn't result in some slow detour 'via' the internal HD?
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Re: glitches in recording; faulty harddrive/RAM?

Postby Richie Royale » Tue Feb 07, 2012 12:50 pm

Doesn't seem likely that there would be any detour. It might be worth checking the preferences of the software you are using, just to be sure that everything is targetted in the right direction.

No antivirus either I presume. Have you been able to try the interface(s) on another computer at any point?

Might be worth checking the activity monitor to see if there is something going on, that you aren't aware of. Otherwise, I'm not sure what it could be, but I'm sure it is maddening for you.
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Re: glitches in recording; faulty harddrive/RAM?

Postby dmills » Tue Feb 07, 2012 12:56 pm

Silly thought, but are you running the latest SMC and EFI firmware?

I don't know if the macbook does the whole SMM thing, but if it does you could be seeing thermal throttling and it is not like Apple have not had problems that way in the past.

Ram is unlikely in this case, as that usually causes odd system crashes not dropouts.
I would hope anything sane would report disk underruns in a loud and obnoxious manner so that also feels unlikely.

Have you checked for any weirdness in the clocking options for the interface, periodic dropouts across multiple applications sounds like a clocking thing to me.

Finally, is there anything in whatever OSX uses as the syslog, sometimes looking at the last page or so of syslog output after plugging in the device can be very informative, same for the last page or two after starting the application.

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Re: glitches in recording; faulty harddrive/RAM?

Postby mjfe2 » Tue Feb 07, 2012 1:04 pm

Sorry to be a newbie but what's SMC, EFI, SMM etc?! I did wonder about clocking, but it's only the Fireface I'm using and I thought clocking had to involve more than one digital interface?
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Re: glitches in recording; faulty harddrive/RAM?

Postby Dave B » Tue Feb 07, 2012 1:10 pm

Daft question : this is the only digital device in the system? No other converters? I was just wondering whether the problems you have a down to bad clocking...

Oops - just re-read the above ... so clocking isn't it then...
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Re: glitches in recording; faulty harddrive/RAM?

Postby ken long » Tue Feb 07, 2012 1:26 pm

what is the sample rate you are using?
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Re: glitches in recording; faulty harddrive/RAM?

Postby mjfe2 » Tue Feb 07, 2012 1:28 pm

ken long wrote:what is the sample rate you are using?

44.1kHz, always!
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Re: glitches in recording; faulty harddrive/RAM?

Postby ken long » Tue Feb 07, 2012 1:47 pm

mjfe2 wrote:it did the same thing on a live recording the other day (which is almost impossible to mend!).

Is that because data is lost? Are you experiencing dropouts as well as / or clicks?
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Re: glitches in recording; faulty harddrive/RAM?

Postby mjfe2 » Tue Feb 07, 2012 1:51 pm

ken long wrote:
mjfe2 wrote:it did the same thing on a live recording the other day (which is almost impossible to mend!).

Is that because data is lost? Are you experiencing dropouts as well as / or clicks?

No dropouts, just occasional buzzes on the recording (not heard when monitoring thro' Totalmix).
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Re: glitches in recording; faulty harddrive/RAM?

Postby Guy Johnson » Tue Feb 07, 2012 3:06 pm

I'd get a diagnostic done, especially if there are potential problems. Have you the DVDs the machine came with? One one, there should be a diagnostic programme. I think you start the MacBook up with it, if memory serves me correctly.
It's worrying that you're getting glitches on other apps like itunes and browser, makes me think there's something fundamentally wrong.
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Re: glitches in recording; faulty harddrive/RAM?

Postby C-Bro » Tue Feb 07, 2012 7:08 pm

Why don't you run
http://www.thesycon.de/deu/latency_check.shtml (xp) + RATTV3

or
http://www.resplendence.com/latencymon

to diagnose your machine?
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Re: glitches in recording; faulty harddrive/RAM?

Postby dmills » Tue Feb 07, 2012 9:21 pm

mjfe2 wrote:Sorry to be a newbie but what's SMC, EFI, SMM etc?! I did wonder about clocking, but it's only the Fireface I'm using and I thought clocking had to involve more than one digital interface?

SMC, the system management controller, a small micro controller in MACs that handles things like fans and power switching, there have been several patches to fix various screwups in this area, and even when right those machines do not exactly run cool.

EFI, the way a mac boots, also handles some low level system configuration tasks. Again there have been patches from Apple.

SMM, system management mode, a special interrupt that can make the processor silently vanish from even the operating systems view while it emulates hardware or handles some exceptional situation (Say overheating). Very annoying from a realtime programmers perspective, but allows things to be 'PC compatible' while missing much expected PC hardware.

Clocking must usually involve more then one digital device, you don't have for example your monitors connected by spdif or something do you?

Of course it could just be a dud interface, they happen to even the best companies occasionally.

Regards, Dan.
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Re: glitches in recording; faulty harddrive/RAM?

Postby C-Bro » Wed Feb 08, 2012 1:09 pm

C-Bro wrote:Why don't you run
http://www.thesycon.de/deu/latency_check.shtml (xp) + RATTV3

or
http://www.resplendence.com/latencymon

to diagnose your machine?

Sorry, disregard this post. Didn't read properly that OP has a Mac!
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Re: glitches in recording; faulty harddrive/RAM?

Postby mjfe2 » Thu Feb 09, 2012 4:34 pm

Update: given the dropouts in Youtube and iTunes I took the Mac in and they're going to replace the internal HD under warranty.

However, I'm slightly concerned that the latest recording I did with an external harddrive also had glitches. It was a busy project though: I used all 8 ins and outs on the Fireface (and of course the 8 ins were were going through the USB buses twice -- Fireface then external drive). My buffer size was set to 512 samples. Do you think it was simply coincidence and this time the computer couldn't keep up? I thought 512 was 'safe', but maybe not when using both USB ports?

Thanks for all the advice btw
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