Dear Wishfulcrystal.
As Michael says, there’s no such thing as “proper pronunciation” of ancient Greek. But there’s no lack of strongly held opinions about it! You can learn a lot for example from this Textkit topic: http://discourse.textkit.com/t/audio-for-classical-texts-in-demotic/15360/1
Some recordings you may want to check out (and I’m going to be lazy and avoid finding the links):
(1) The lectures and readings (including the entire Iliad and Odyssey) of Stephen Daitz, available from Bolchazy-Carducci. Many people have an adverse physical reaction, literally, to what they perceive as Daitz’s extreme shrillness, but you should check his readings out, they’re kind of a classic.
(2) The CD’s that accompany Oxford University Press’s Athenaze and Cambridge’s Reading Greek. If I recall correctly, the Athenaze recordings start with a guide to (classically restored) pronunciation as well as pitch, and they use pitch in their reading of the first few chapters, before abandoning pitch and simply using stress. Many English-speaking people, at least, I would say probably the majority of ancient Greek students (including myself), abandoned our efforts at pitch as just too difficult and impractical. Again if I recall correctly, the Reading Greek recordings (also using classically restored pronunciation) stick with pitch. But in both cases, the recordings are only for the first few chapters of the respective textbooks.
(3) A personal favorite of mine was Le Grec ancien (part of the French Assimil: La méthode intuitive series). The accompanying recordings cover the entire book (of 101 lessons), so you get a sustained experience, and they are very clearly articulated. I don’t remember exactly what they do with pitch. I recommend the book itself, if you are just learning Greek.
There’s lots more out there, but to narrow the search: Is your intention to learn and use the classically restored pronunciation, or Koine, or modern Greek? (And I’m assuming you know the difference?) Are you learning and practicing your pronunciation in your early stage of learning Greek, or is it more that you’ve learned the fundamentals of Greek and have reached a stage where you want to improve/perfect your pronunciation? If the former, you probably want to pick an approach and stay with it consistently. If the latter, you may be more willing to experiment.
Randy Gibbons