Hi,
if you want a good experience with the SX do not use the wasapi mode again for your favorit live audio manipulation software.
Switch back the MIDI mode (.. so you should Run SERATO Dj ) to Normal.
next step - take a look at the Serato website, there you can find a lot of tips to Optimize your PC ore Mac to Work with seratodj and the DDJ as well.
https://support.serato.com/hc/en-us/categories/200176274-Troubleshooting-Optimization
If you use a Windows Operating System try to RUN LatencyMon to figure out that your Computer is Running without ANY interuptions (produced by drivers ore malware infections etc.)
http://www.resplendence.com/latencymon
Try to setup your DDJ-SX for SeratoDJ cause the Device was build for that.
good luck
