Another plea for help concerning latency and audio card settings

I've been using Sonar for many, many years and I've rarely had a problem with latency,  I have a pretty decent computer (specs below) and I'm wondering if I need to change any settings.
First here's the problem:  I'm working on a project that has 3 vocal tracks and 6 midi instrument tracks.  The three vocal tracks are all sent to "Bus C" which has iZotope Nectar in the FX bin.
A couple of the vocal clips have Melodyne on them (which I think might be a big part of the problem right there)
The instruments (all VSTi) include Real Guitar, Superior Drums, Kontakt Bass, Kontakt Percussion, True Piano, and finally RealLPC with TH2 added in the FX bin.
ALL of the virtual instruments are FROZEN, (bounced to an audio file) with the exception of the RealLPC guitar, which I'm trying to lay down a lead guitar part.

Everything plays back fine until I try to play notes on the RealLPC instrument, then I get about a full second or two delay.  When I stop the playback and reset the MIDI and stop/start the engine, the instrument will play fine UNTIL I start the playback again.

So here are my settings:
I'm using an M-Audio Delta 1010LT (latest version driver) set at:
44100, Asio Buffer 128 samples.   (I've also tried 256 and 512 sample rates)

In Sonar X2 the settings read:
44100 sampling
Input 3.9 msec  171 samples
Output 3.5 msec   156 samples
Total roundtrip 7.4msec and 327 samples
Playback buffers (both In and Out) are set at 256
Enable R/W caching are both UNchecked.
Use Asio reported latency is checked at 327 samples
 
And my system is as follows:
AMD Phenom II X4 945 3.0GHz (Quad Core) 45nm, AM3 6MB Cache
MOTHERBOARD: ASUS M4A785TD-V, AMD 785G, Onboard Video, HDMI, GB LAN, iEEE
RAM: 16GB (4x4GB) PC10600 DDR3 1333 Dual Channel
GRAPHICS CARD: NVIDIA GeForce GTX-580    Driver: 301.42
AUDIO CARD: M-AUDIO DELTA 1010LT
Corsair 850W ATX Power Supply
 
Sorry for the long post, just trying to give as much info as possible.  If anyone can see any adjustments I can try tweaking, I'd appreciate if you'd let me know.
Otherwise I'll just have to bounce the entire mix into a stereo wave file and just add the lead guitar into the mixdown.  But I'd rather not do that because I'd still like to adjust the vocals and other instruments after I lay down the lead guitar part.

Thanks again for any advice or assistance!!!
Lee

Silicon Audio


Have you tried systematically going through all of your effects and turning them off, one by one? Chances are, one of them is a high-latency effect and when you stop the playback and reset the MIDI and stop/start the engine, the PDC is turning off, allowing low latency again. The fact that you can actually get the latency low again pretty much rules out your sound-card latency. I bet it's one of your plug-ins.

Okay thanks!  I'll give that a try.   As I said, for some reason I think it might be the Melodyn plugin.  I seem to remember having some latency issues in the past with that one.
But, I'll give them all a try one by one and report back with any results.   Thanks again!

Thanks Bob, that link you posted kind of just confirms my su****ions about Melodyne.  (why would the forum block out the word su sp ic ions?  Oh...I see why, that's just dum-b.) I also have Auto-Tune and of course V-Vocal, but I like using Melodyne the best, it's easier to work with and it has a nicer UI.
I'm going also try bouncing the Melodyne track down to a new audio track so I can take the Melodyne plugin out of the equation.   Thanks for checking into this for me.

One other question, do my settings look pretty typical?  Every time I do a search for "best settings" to get some rough guidelines, I get a different answer for each search.  I always get confused about sample settings.  I know the basics, but anything beyond that makes my head hurt.
 
Specifically these settings:
Input 3.9 msec 171 samples
Output 3.5 msec 156 samples
Total roundtrip 7.4msec and 327 samples
Playback buffers (both In and Out) are set at 256
Enable R/W caching are both UNchecked.

robert_e_bone


There are folks that truly obsess over that stuff - if it works and you are happy with it, spend your brain waves on more productive thoughts, like what to get me for my birthday later this month.......

Everything looks fine with your settings, 

Bob Bone

 
Thanks again Bob.  I've been doing some reading in the highly recommended book "Sonar X1 Power!" by Scott Garrigus.  And tweaked a couple of settings according to some of his suggestions.  For example I changed the Input and Output buffers to 128, but I got a crash half way through the song, changing it back to 256 seems to be the right setting for me.

But more importantly I think I found the culprit.  I turned off all the efx and turned them back on one at a time and it seems to be iZotope Nectar is the problem.  It's used on one of my busses that handles the three vocal tracks.  I turned that off and turned everything else back on, including Melodyne, and now I can play the (virtual) lead guitar part during playback and record with no latency at all.   I guess Nectar is one of those high-latency plugins.   So, I'll just keep it off until I'm done with all the instruments and just turn it back on for final mixing.