VAS(Virtual Audio Streaming) can record sounds without problem.
It is probably that the crackling is caused by small buffers and slow CPUs. Some old computers with small buffers cannot send VAS audio data to real sound card in real-time, which causing crackling.
1) To fix the cracklings, try modifying the 'buffer' size to a larger value:
Click stop button, change the buffer size to 4096 or other bigger value, then click start button again.
2) Finally, even your buffers and CPU performance are too low to hear smooth sounds, the final recorded wav files should be always no problem, without crackling. Low performance only impacts what u hear audio, not the recorded files.
Also note, the crackling/delay may be caused by the limitation of our trial version. See:
http://www.virtualaudiostreaming.net/faq.html