I'm using a USB midi keyboard (Arturia Keylab) and a variety of software-based keyboards and synths. Most often I used Arturia's Analog Lab application. The Audiobox iTwo takes USB from the computer and provides the signal to my powered monitors. So, when I'm just practicing, the Audiobox is functioning as an external soundcard. PC is running Windows 10, core i5 processor, 8GB RAM, SSD drive.
When I play complex, layered synths or play fast on the keyboard, there are audio glitches (pops? crackles? sounds similar to an overloaded input) that are heard through the speakers. Even if I load up Analog Lab or other VSTs in Ableton or Reaper, the same sonic glitches occur. The commonality appears to be when Audiobox ASIO is the selected audio driver in Analog Lab, Ableton, or Reaper. If I change the various software to use MME/Direct X, the audio glitches stop. If I use a different brand USB audio interface (with their appropriate ASIO drivers), the glitches don't occur.
I've tried ASIO4All and experienced marginal improvement but it's not 100%. I've tried various ASIO buffer sizes and found that the larger the buffer, the more glitches occur. Right now the buffer is set at 256 with a latency around 9ms and glitches are still there, albeit at a lesser amount.
Assuming the culprit is ASIO, I'm curious as to why/how the lower latency of ASIO exhibits problems when the higher latency MME/Direct X drivers do not. Note: I never experience glitches recording analog audio into the Audiobox iTwo using either the Presonus or ASIO4All drivers.