[tux3]

How close is broad ballpark, have you tried chromaprint?

It's probably far from state of the art today, but you can get a percentage similarity out of it. I've successfully used it to find similar (or outright duplicate) songs in a big library

[Lerc]

Things like chromaprint are why I have found it difficult to search for what I want.

These tools are geared towards identifying matches (one to many) Chromaprint specifically bins things into notes assuming it it trying to match music.

I'm after something that will tell me, in human perception, how much a dogs bark sounds like a quack.

One to one comparison of short-ish samples with no assumption of content style.