I couldn't figure out the audio captcha. People who are blind probably have better hearing, so maybe it's easier for them.
I've heard a lot of anecdotal evidence that young blind people have better-than-average hearing, but what about the elderly?
I'm not sure anyone I know over 70 years old could pass either of those captchas. I guess the only consolation is that most people that age often have younger people sign up for them.
I certainly couldn't. Perhaps they rely on blind people having heightened auditory senses.