IDG Answers is a community of experts who are passionate about technology. Ask a question or answer one below.
It might be your sound card, but it also could be bad electrical wiring or something causing electromagnetic interference. If your sound card has poor shielding, it can cause exactly this “crackling” sound if there is a source of EMF nearby. You might want to try moving your PC to another power outlet (preferably on a different circuit) to see if it makes a difference. If you are in an older building with original electrical wiring, this is certainly a potential cause of the sound issue.