Clocking Problems

[Foreverain4]

I am running a Dell 1ghz P3 with a Gadget Labs Wave Pro 824 that has a digital spdif input. I also have a Kurzweil PC2X that i am trying to run into the spdif input. Whenever i record at 48Khz (which is a must because of the sample rate of the PC2x) I get all sorts of pops and glitches. Now here is the weird part, even when i record the keyboard through the analog inputs at 48Khz i get the pops and stuff. My only option at this point is to record through the analog inputs at 41.1Khz. Anyone know more than I do?:)

[recordingpro]

if you record from another source (ie a guitar processor, differant keyboard etc) via the analog inputs are you getting the same results ???

also, I'm curious about a couple other things....are you recording at 24 bit? do you have a seperate hard drive for your audio or are you on the system drive? Are you using a true coaxial cable or are you using just a standard rca cable ?

[Foreverain4]

I do have the same problem recording a source such as a microphone. I am recording 24 bit, but I also get the pops when recording 16 bit 48Khz. I have two separate hard drives, one for apps and one for all my audio and video files. I am using a video quality cable, I am not sure if this is the coaxial that you were talking about.

[recordingpro]

just to clarify....so when you record at 16 bit 44.1 everything is ok? no clicks or pops?

[Foreverain4]

that is correct. and also 24 bit 41.1Khz.

[recordingpro]

Wow, Thats pretty interesting...and unusual. That blows every theory I had to pieces....I would say that it really sounds like the card might have a problem with it, but I don't know. I'd check with whoever you bought it from and see what they say.


Good luck ( and let us know if you find out what the problem is)


Anyone else have any suggestions ????

[Clay Stahlka]

Here is the skinny, just so you all know. When you are digitally recording from a source that is using its internal clock, (not word-sync'd to a house clock) then that source device MUST be the master clock over all else, period. There is no other way around it. So, if you've got any other digital devices in the chain, they MUST be slave-clocked to the source master. With keyboards, most DAT machines, mini-disk machines, etc you are usually screwed. You can only use the source and destination recorder at-a-time. This forces you to track parts separately, one keyboard or module, or digital player at-a-time. Of course, if you have a master house clock and all your devices had a word-clock input then you could put it all to rest by having everything slaved to a master clock source, not to mention that it makes everything sound better too.

Now on to your specific issue. You might check to make sure that your software is set to slave to clock from the source device. (read: not set to internal 48kHz clock.) This is almost certainly the problem, because the Kurzweil can only be master and can only output 48kHz clock. The cable might be a problem, if it is either really long, or really poor quality. s/pdif coaxial cables should not be longer than 10-15 feet in most cases. If you are running at the extreme of the spec, like 10-15 feet, then buy a really good 75? digital audio cable, like the Wyde-Eye Apogee or the Monster. If you're running a 3-6 foot cable or something, then, while a good cable always make things sound better, it is not the problem! Cable quality increases jitter which makes the stereo field collapse, and harms the extended frequency response range, but usually it has to be pretty bad to introduce clicks and pops.

I hope this helps you understand the big picture which can help you solve this issue and any future issues that may "pop" up. -cs