Here are some possible causes and solutions:
1. VPN. If you have a VPN enabled, you should disable it since the voice quality and connection are likely to be poor over VPN.
2. Your internet. If your internet connection is poor, then you may have issues with voice connectivity and the player might lag.
3. If all else fails, check your voice region by going to the voice channel's settings. Try setting it to either US East, US South, or US Central.