Variable Latency???

This is a bit wordy but I've tried to capture the important facts.I've read what I can in the forum to try and uderstand latency, and and set up my gear correctly. I have a cheap nasty laptop (1.6Ghz 2M ram) and and M-Audio fastrack set to meduium latency. Reaper reports 11/12 ms in the top right corner. I'm monitoring directly when I record. I'm not getting pops or dropouts Things were ragged until I learnt about the loopback test and discovered that I needed to manual offset by 582 samples to get a click source and a recorded copy of it alligned on playback. Great. Start new projects. Feels good. By about track 10 I'm starting to loose it on the timing and feel, and wonder if I'm just tired or there's a problem. I've got a simple Ezdrummer beat, bass, two electric and one acoustic guitar laid down, with sprinkling of comps and EQs applied. Nothing renederd. Performance meter says about 60%. Is that excessive? I attempt to add some keys, sounds good when I monitor directly (well it would) but oh dear! Its out of time on play back again. I check the loopback and find that I'm now out by a further 700 samples or so, even though all the setting in Preferences are unchanged. I recalibrate and add my ham fisted keys. It then occurs to me to sart a new project and check the loopback with unchanged setting. To my great surprise, I now find that my recorded click is ahead of the source click by a few hundred samples. Question : Does /should latency vary dynamicaly with the complexity of a project. mine seems to, and I'm wondering how to manage? Thanks in advance to anybody who might spot the eror of my ways.

Alas, really hard to tell what's going on there. First off, this is not directly related to PDC, the problem seems to be that the M-Audio driver is not reporting the proper latency to Reaper in first place. Then, using manual offset to compensate is ok as long the sample rate doesn't change, then the values change. Is it possible that you changed sample rate in the course of tracking?

Thanks for replies Shakey ans Steindork. So, having to shift something back in time is common practice after every take when you want to mix or edit? Doesn't sound too practical, or maybe I'm missing something. I don't think I changed the sample rate. Is it possible to do that as a consequence general track or effect combinations? Thanks UK Steve

edit: nevermind, i'm braindead today.

Success ... maybe 

Hi, So I just updated the driver for my M-Audio Transit. Loopback tested and corrected by 25 samles and all is well. Tried the trick of starting a new project, and guess what, the loopback stays in synch. Fingers crossed from here. thanks Steve

I am having the same problem with my Echo Audiofire 12. My actual latency (which is significantly more than my Audiofire's reported latency) jumps around by a hundred or so samples for seemingly no reason. I can save a project, restart the computer and open it up again, and my latency compensation will be off. It can happen while working in a project as well. It is happening in Reaper as well as Sonar. I am on an xp sp3 system and am using the firewire port built into my motherboard. I am going to order a pcie firewire card with a TI chipset to see if that helps at all. (Could anyone recommend a specific TI chipset to look for?) Thanks, Ben

Thanks for replying Karbo. It's definitely not a sample-rate issue as the latency changes without any adjustments to the project. I have experimented with different drivers (older and newer) and it hasn't seemed to help, but I could explore that angle a bit more. Best, Ben