Phaldage says the phollowing:

and I parbly don' need to tell most of you this...The Classical Greek phi was not an unvoiced labio-dental fricative nor even an unvoiced bilabial fricative but rather an unvoiced aspirated bilabial plosive (the pi was an unvoiced unaspirated bilabial plosive).

Not only did you need to tell me that, but you need to explain the difference (if you'd be so kind).