Someone has left the following comment on a music video on youtube: 「Crying End Rollは名盤、はっきりわかんだね。」
Crying end roll is the name of the album, which the song in the video is on. is わかん a shortening of わかる？
わかんだ is not used in modern standard Japanese. If this ん were explanatory-の/ん, it requires a dictionary form of before it. わかるだ/わかんだ exists in some Eastern/Nothern dialects, but it sounds fairly provincial.
In fact, this はっきりわかんだね is one of so-called 淫夢語, an Internet meme based on a certain gay porn video series. Semantically it just means something like "That's for sure." Some words originating from this video series are quite popular among net users, and many people are using them even without knowing their origin.
Anyway, はっきりわかんだね is broken as a proper Japanese expression. Use it only when you know what you are doing.
EDIT: As @goldbrick pointed out, there are cases where 分かん, 飲めん, 来てん, and such can directly attach to だよ, だな, だろ, etc. They sound rough but not particularly dialectal. 分かん can be a sound change of both 分かる and 分かるの, depending on the context. Nevertheless, わかんだね sounds rare to me, presumably because it's a mixture of rough and mild expressions.
Yes! I think so.
はっきりわかるのだね。---> はっきりわかるんだね。---> はっきりわかんだね。