Audio skipping (dropping samples?) when recording from digital mixer to computer

J

jethro

New member
Someone please help!?!?!
I am at wits end trying to set my computer up for hard disk recording. It seems no matter what I try, I get random "skips" in the audio. I believe samples are not getting recorded. Sometimes it may sound like a "click" as well. I think I've tried almost everything, but thought I'd post here just in case someone has had this problem.

Here's my specs:
Athlon 500 w/ KX133 motherboard; 256Mb RAM; 2 hard drives (IBM Deskstar for recording, both set at DMA); RME Hammerfall sound card with latest drivers; Matrox G400 dual head video card; a few other cards (network, modem, scsi, etc.) - note: RME is on own IRQ (5);

Also, Fostex VM200 digital mixer to convert analog to digital using ADAT lightpipe as connection.

I've tried:
- All types of sync, from ADAT lightpipe with Fostex as master to ADAT lightpipe with card as master (card shows "sync" for ADAT in.

- Word clock sync (with both the mixer as master or the card)

- Disabling all other running programs

- Unplugging USB connection

- Altering buffer settings

- Has problems whether recording into Cubase or SoundForge

I can't remember now what else I've tried. If anyone can help in any way, I'll be forever indebted. Thanks!
 
Have you tried defragmenting the discs? I think you'll find that your disc is really messed up if you haven't defragged it on a regular basis. Let the defragmenter run over night and I'm pretty sure you'll get better results.

Cheers

/Ola
 
Yes, I've definitely defragged the hard drives. The problem still existed when I first installed the second hard drive (it was totally clean). Thanks for the good advice, though!
 
Did you assign an IRQ for the Matrox G400 and USB ?
I had similar problems, the solution was assing an IRQ for all internal hardware and look for IRQ-sharing.
I think the RME doesn't support IRQ-sharing with other cards. Also check if your RAM timing is right. Maybe switch from "turbo" to "normal" or try it with 128 MB.
Go to the device manager click on PCI-Bus and change the IRQ-settings.
 
Hey Frieberg, thanks for the reply.
Did you have the same "skipping" problem or was it just random "clicks or pops"? I can't alter IRQ settings through device manager, it says "The resource setting cannot be modified". And the RME card somehow magically ended up on it's own IRQ (5) without any other devices. I'm not sure how to adjust RAM timing. I'll check the bios for anything obvious. I know I have it set at 100Mhz (my memory speed). Did these adjustments help fix your situation?? Thanks again for the help.
 
ok, jethro.. Im gonna ask you to describe your cabling set up, between your mixer and your soundcard.. cuz this sounds like a straight timing problem if you ask me.. not a hardware issue. (but god please dont hold me to that!!)

tell me what connections you have, how long your cable is, what kind of cable, and what connectors on the ends... hell even what color it is!

xoxo
 
My current cabling is as such:

ADAT lightpipe cable Out from VM200 to In on RME.
ADAT lightpipe cable Out from RME to In on VM200.
Both cable were purchased new and are HOSA Fiber-Optic cables, 5M (16.5 Ft.).

When I installed the daughterboard with Word Clock In & Out I hooked up a coax Word Clock cable (not sure of brand) from the Word Out on VM200 directly to the Word In on RME. This cable was about 15 Ft. or so.

I'll give shorter ADAT cables a try, but I think I had the problem when I was using these. (my mixer is too far away for the short cables to work efficiently).

Thanks again for any help. I spoke with a Fostex tech support guy this morning, and he said that he had never heard of the mixer causing this kind of problem. The next thing I might try is setting up a different Hardware Profile in Windows and turning everything but the bare necessities off. Anyone have experience doing this? Is there a risk?
 
Sounds like you have clocking problems, every digital studio needs 1 and only 1 digital clock. If you have 2 clocks, you have garbage clicks and pops. You are correct, the clicks are actual samples that are being skipped.

Designate the mixer as the master clock, and set ALL other digital audio devices to be slaves to that clock, ie...to receive clock from the digital mixer and not use their own internal clock. You could also purchase a stable clock source and designate that as the master.
 
Listen to ET.. I think hes on the right track.

So, now that your cabling looks good.. what are the clock settings on your MIXER, your SOUNDCARD and your SOFTWARE..?

xoxo

ps TDIF ROCKS!!
 
Hey guys, thanks for the replies. Sorry for the confusion. I only use 1 master clock source, I've just TRIED about a dozen different options. Usually, the Fostex would be set as master and the sync would be over the ADAT cable. But I've tried the card being the Master, and using Word Clock sync with either the Fostex or the RME as the Master. Nothing works.

I'm not sure if it is a clocking problem. I seem to be getting sync. And I know what "clicks & pops" sound like. This is different. There is actually a very small chunk of audio that doesn't get recorded, which makes the music "skip". It's especially noticeable if it's near a drum beat, as I can hear the beat "speed up" or miss a beat. I think it is either the mixer not transfering the samples, or the computer getting distracted by something momentarily. BTW, last night I set up a different hardware profile with JUST the RME and my video card enabled. I also turned the video acceleration almost all the way down. So there should have been nothing to interupt the flow. Unfortunately, it didn't work. Then I tried my Soundblaster Live card (analog in), and it seemed to do fine. Hmmmmmm. Anyone know advanced BIOS settings or something??? Thanks!
 
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