Voice not picked up by original sound

[Lotus]

I regularly facilitate Buddhist practice meetings that involve the use of a bell. Previously I had been able to put original sound on, I could invite the bell, which carried beautifully for everyone to hear, and I would be able to speak and be heard clearly. Over the past couple of days this has stopped working. Now people can barely hear me speaking when I have original sound on, so I am having to toggle between original sound on and off every time I want to invite the bell and speak, which is multiple times during meditations. 

Has something been changed? What can I do to fix this? It is not a relaxing experience for me to be facilitating meditation and having to think about toggling sound settings on and off throughout the sitting. 

Thank you 🙏