You need to adjust the buffer size & number of buffers in the settings. Go into the settings, and switch from "Wizard" to "Expert" and through trial & error, you can try to see how far you can reduce those before the audio starts to break up.
Do the input first, making sure the test doesn’t crackle. Then do the output as low as it’ll go before it crackles at all. At that point you should be pretty close to as low as it’ll go without every crackling or stuttering. You might have to increase the input and/or output slightly from there if you system comes under heavy load and crackles, otherwise enjoy.
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