I have had Studio One 4 for a while now. In fact, I've had it since SO3 died. Throughout all of my use, I've never had this problem.
When it lags or there is minor static, I've increased the device block size (I think it is alternatively known as the sample rate?), and that has done the job. And I also keep searching online for answers, and that's what they say fixes it. But a few days ago, I opened up Studio One 4 and I created a new AudioBox USB song. I hadn't even added anything yet, but it was popping and cracking quite loudly. I adjusted the device block size to 2048 samples (the highest I could go) and it kept popping. When I click the button that allows you to deactivate the recording abilities of a track, the popping stopped. I even deleted the tracks and made new ones, yet that did not help me at all, for when I clicked the button that allows the track to record, the popping broke my eardrums (not literally).
If anyone has any suggestions, I'm open to any and all to fix this problem.