Digital Ticks

[winter20]

Merry Christmas Everybody,
As always even during the busiest times i've managed to squeeze in some PT and DUC time [img]images/icons/smile.gif[/img]

My problem is that I'm getting sporadic occasional "digital ticks" that are printed on my waveform. I've been redrawing them with the pencil too to fix them but this is annoying and hopefully a solveable problem.

The ticks are printed on the waveform as a single spike but occur both up and down and on all parts of the waveform.

In a typical 30 second take (i'm a hiphop producer) I'll get maybe 1-2 ticks. Sometimes none sometimes more.

I'm running at 128 or 256 buffer usually at 85% CPU.

My system is
MBOX
AMD XP 1900+
768 MB RAM (Kingmax 333 PC2700)
ASUS A7V333 (no raid)
ATI RADEON 7500 AIW
IBM 80 Gig HD
Windows XP with SP1.

I've got the latest firmware on my mbox and pretty sure most of my drivers are up to date but if you know of drivers that may cause this problem lemme know too.

So if any of you have had similar problems and are aware of a solution for digital ticks, please let me know.

Thanks, be safe over the holidays,
winter

[Bastiaan]

Are you connecting to a digital device? If you do, you should slave ptle to that device....

[winter20]

Hi,
Sorry I should've mentioned - the only things I record are via the Analog inputs - so using the mic preamp or just the standard 1/4 ins.
Keep the suggestions coming please!
Thanks,
Minh

[CRM-114]

I get such ticks in my vocal tracks, and I'd also like to know how to avoid this. I use a pop filter, but it doesn't completely eliminate that problem.

[Dr.John]

Are you bouncing to your system HD? If so, that could be the problem. You should only bounce to a 2nd HD.

Dr.John

[evilchopper]

Since your spikes go up and down, I agree with the clock suggestion, this should clear it up. If your spikes were only one sided, one possible source of such spikes is typically static discharge, This occurs in the analog domain, before the analog signal is converted to digital. It is commonly caused by poorly grounded preamps, poorly grounded cords, or even just static buildup on the mic or components themselves.
I suggest replacing each component from the mic to the 001, one at a time to see if you can find the culprit if you encounter one sided spikes.
Any devices using a wall wart (a step down AC/DC converter)may need an additional ground strap attached from the unit to your main ground.
I connect all my devices with groung straps and haven't seen a "spurious ground discharge to unity" since doing so. (they were prevalent before this step)
Good luck, don't give up

Chopper
Black Pug Digital Discworks
www.evilchopper.com

PS I once had similar spikes when I used a regular coax instead of an S/PDIF cord with the proper impedance. Went away as soon as I used the right cord. Another clock related issue.

[winter20]

Thanks for the tips guys.
I get the ticks during the recording session before any bouncing. Right after I finish recording and just playback my take the ticks are there. But I am using just a single hardrive for everything on my computer. Could this be it? I'm not having any performance issues with PT, just the ticks.

Thanks for the info regarding grouding - I'm running an MBOX not an 001, but in terms of surge protection or extra grounding right now i just plug my computer into a power-strip which plugs directly into my wall and the MBOX uses USB power from the motherboard. I'm using the stock USB cable, have any users our there upgraded to a shielded, longer or just superior USB cable? Do such things exist?

Thanks again, more suggestions would be greatly appreciated!

[Shannon Dunn]

This sounds very much like a reclocking tick. This occurs when two digital devices are connected together and not properly clocked together. Basically, the processers keep attempting to reclock to the signal to keep in digital time. You can reproduce this effect by putting your card in 44k mode and feeding a 48k signal to it. Then simply record a blank track and listen to the occasional slight ticks as the processer tries to reclock itself to the incoming signal.
Whenever you connect two digital devices together, you are actually connecting two cpu's in series. All digital devices have a cpu that processes the audio signal in the digital domain. This is why clocking is necessary. The CPU's have to have a reference as to where the sine waves begin and end. Without one of the devices being the master and all other devices being the slaves to that master, there is no reference as to where signals start and end. Therefore any cpu's in the chain will constantly attempt to adjust their processing in relation to the incoming signal. Hence the ticks as the processer readjusts itself.
When you connect any digital devices via adat light pipe, they must be properly clocked. (Signal clocked) When you connect tape based devices to digital devices, then they must be word-clocked as well(this gives the tape based device a reference to slew it's servos to the digital device it is communicating with). Many people think that if they don't use a tape based device like an ADAT tape recorder, then they don't need to clock the devices together. But this is erroneous. ALL digital devices must be clocked to a master if they are in a chain of any kind. And tape based systems must be word-clocked as well. No exceptions. The only time a digital device does not need to be clocked, is if it is operating by itself(ie., it is essentially it's own master).
A lot of people never realize their system is out of sync because they only record very loud material and never have a soft enough passage to hear the reclocking taking place. So they use their system for a long time thinking nothing is wrong, until they finally discover the notorious ticks. They then mistakenly assume that their system has "developed" some sort of problem. But truth is, it was always there. They simply never properly clocked their system.