Audio captchas are pretty hard to solve for me personally, much harder than even almost unreadable Captchas. But maybe that's just me. Still can't imagine a bot solving the audio captchas I've heard though.
Wow yes I agree first time I hear reCAPTCHA. I am seriously wondering whether ANYBODY is able to solve this. I know it was broken before but now it seems reCaptchaing something means straight up denying it to visually impaired people.