It's definitely a toy and a bit dodgy. I wrote up some instructions over here: https://github.com/Katee/quietnet/issues/3#issuecomment-3187...

Basically I only every worked on this until it was at the point where it was working for me on the laptops I was using, it's definitely not robust.

I have a 13in Macbook Pro and the internal speakers were not working for me. However, I plugged in my higher quality headphones and held them up to the speaker and it worked. It might work if you plugged in external speakers.

Are you sending and receiving on the same computer? I feel like that might cause issues. Are you able to use two separate computers to test?

It actually works much better when sending an receiving on the same computer. It's not as fun though.

Now that I've thought about it more, that actually makes a lot of sense. Thanks for the response!

Make sure you are in a quiet room (with the AC off). It worked for me on a Macbook retina, but started to fail when the AC turned on.