Safari is really a bit difficult. It should work as it is , but it gets the audio devices messed up. And ends up recording silence.
i) confirm you have a red mic icon in the safari address bar.
(if not it means the site has not been granted access to mic by browser. Check permissions for the site)
i) plugin iphone headphones into the headphone jack and reload the page
ii) reboot the mac and try again. If you change mic settings in the system sound settings, or possibly even after plugging in headphones, a system reboot might be needed to make the settings apply.
You can tell Poodll to use HTML5 audio recording on Safari, or Flash by toggling the following setting in the Poodll filter general settings. But probably the outcome is the same either way.
If those steps above do not help, then I think the best solution is to use Google Chrome