OK - don't panic, we'll get this figured out (he expresses hopefully). :)
Can you please detail your system specs, such as how I have mine listed in the signature section of this post?
(I actually recommend you edit your forum profile's signature section to add your specs. Lots of us in the forum do that, so that when we post issues, others can immediately get an idea of what our systems look like, and that greatly speeds up the problem solving process in a lot of cases. To add your specs to your forum signature: go to the top of the forum page, click on User Control Panel up in the top right corner, then click on Signature and Comment, add your specs, also making SURE to check the box that says 'Always attach signature to post', then click Save Profile).
So, the whole thing about the ASIO Buffer Size and latency, and having to flip between low and high, depending on what you are doing and all of that:
When you are using WDM drivers, Sonar DOES provide a handy slider for adjusting Buffer Size, and that's cool, but it only works when using WDM. When you use ASIO drivers (which is most likely the best choice for you), you have to make the Buffer Size adjustments through the control panel for your audio interface.
When you are in the process of RECORDING tracks, you really want to get things set up to where your Total Roundtrip Latency is down around 10 milliseconds or a little bit less. If your latency gets much above 10 milliseconds, you will begin to hear a bit of a 'lag' and the sound can become problematic.
When you are finished recording, and move on to MIXING, you will have to adjust your ASIO Buffer Size way up, to allow the inclusion of the kinds of effects that use 'look ahead processing', where they load in data ahead of what is playing, in order to do particular kinds of effects processing. These effects are designed expressly for the mixing/mastering process, and NOT meant to be used for recording tracks, because the way they do their thing requires a much larger ASIO Buffer to support reading all of that data ahead of time.
SOOOO, when you work with projects, you basically have the 2 kinds of requirements for ASIO Buffer Size: small for low latency when recording, and large (even huge) for high latency when mixing/mastering. This is a basic fact of life when working with any DAW, such as Sonar, and you will, over time, get used to adjusting the ASIO Buffer Size when needed, and you will also become aware of the IMPACT certain plugins have on projects - meaning that you need to be careful in the recording part of it not to load effects that induce large amounts of latency.
I am guessing that if you were to set things at: Driver Mode ASIO, ASIO Buffer Size of 128, Sample Rate of 44.1 k or 48 k, Record Bit-Depth of 24 bits, and a Total Roundtrip Latency of around 10 ms or a little less, that in a NEW project, you would not likely have any dropouts, lag, crackles, or noise.
So, just for a test, try the above settings in a new project, with just a small number of synths, and make sure that things record with no sound issues.
OK - so that's a crash course on some of the ASIO Buffer Size stuff. Back to the current nightmare.
I do not yet know your system specs, so this is conjecture, but I am wondering if perhaps you might try a test where you 'freeze' your synths. (do this on a backup copy of your project - since this is for the moment just a test).
Here is some Sonar documentation on Freezing:
http://www.cakewalk.com/Documentation/default.aspx?Doc=SONAR%20X3&Lang=EN&Req=Mixing.23.html Scroll down to the section titled; To Freeze a Soft Synth.
So give the above a shot and post back.
Bob Bone