Would love to know if you got an answer to this. Everyone says the 2 way audio works but mine has yet to work. I have not plugged in an external speaker - there is nothing in the directions that says you have to have an external speaker/mic. Please, if you've got any update that would be great, because otherwise...this thing is useless to us as a baby monitor w/out audio working.
I have 3 of these (from different rebranded manufacturers), one is this HooToo. On two of mine, 2 way audio works fine, but on 1, I can't seem to talk back, but I can certainly hear what's going on. You don't need any additional equipment. It has a built in speaker and mic. The other thing to check, is that you are running the website with Active X enabled fully. This could be one reason why you can't use 2-way. This webcam also works well with TinyCam on Android. I can do all functions from my phone, including 2 way audio. Personally, I use the webcam to watch the baby, but rely on a separate baby audio monitor.