What is the platform you're using (Mac, PC, iPhone, iPad, or Android)? Are you able to record separately on the devices's default voice recorder app, and if so, what is that sound quality? Have you attempted to uninstall Rush, restart your device, then reinstall the app?
Hope this helps! Make sure to press "✔ Correct Answer" on this post if this answers your question. Happy Creating! Anissa • @anissat