Important feedback on the live demo page: Make the default output sampling rate a normal talking speed. Right now it defaults to the highest rate if you don't set it / know which rate is best. First thing I did on the page was click the mic. The voice was too fast, and since the active mic disables the settings, I thought I couldn't change them so it might be broken. Also you want to make it clear that you can change the settings by turning off the mic. That took me a while to figure out.
Again, well done!