Better sound recording

Looking for some help / best practices. I have a client who says that the sound recordings I've made on some slides are not loud enough and/or have background noise. I've not run into this before. I have a very good quality headset and mic that I bought just for this type of recording.

I just found the "Sound Options" tool. It looks like the volume is set at "Min" - should I increase this? I also already changed the sound volume to "high" on each slide.

Not good with some of this tech stuff and just trying to avoid too much trial and error if possible.

Thanks,

Ken