… referring of course to the iconic brand of fishing lures.
I’ve been fishing with them for more than 40 years. I’ve always pronounced it “ra-PAH-la”, and the countless fishermen and women I’ve met over that timeframe pronounced it the same way.
But I recently came across a fishing show on the tube, and the guy pronounced it “RAH-pa-la”. This was disconcerting to me.
So which is it? Was the TV guy reading his teleprompter wrong or am I the victim of four decades of ignorance?
I’m sorry to inform you that the latter, TV guy pronunciation is right. Rapala is a Finnish surname (company founder), and the only Finnish way to pronounce it is with the emphasis on the first syllable.
I was quickly corrected by my Finnish wife who speaks the lingo. The emphasis is on the first syllable. They also pronounce Sauna differently, they think they invented it as well 
Well that’s a bit of a head-twist… 40 years of pronouncing it the wrong way.
Nevertheless, I shall continue to say "ra-PAH-la, and chalk it up as a regional (Great Lakes) quirk of speech. If any Finns deign to correct me, I’ll smile knowingly and say “whatever”… 
Heh, that’s funny. I’m a Finn (mostly) from Minnesota, and everybody I know pronounces it RAP-ah-lah.
OK, instead of “Great Lakes”, we’ll call it a Michigan thing.
(now let’s hear from all the Michigan folks who’ll force me to further micro-regionalize. ). 
The stress in Finnish, as has been stated, is on the first syllable. There’s an article here I found that suggests that vast majority of English speakers stress it as the OP does, on the second syllable. But their own website says to stress the first for the “correct” pronunciation. Of course, if you really wanted to be true to the Finnish, you’d have to trill the “r,” as well.
Congrats on being an American BB. That bestows upon you certain privileges - among them being the privilege to mispronounce foreign words and company/product names in whatever way fits closest with english.
Be advised, this privilege only applies within the US (“When in Rome …”) and does NOT apply to personal names.
Note: I’m only joking about the American privilege part. I expect most people in all countries will adapt foreign words to fit their own linguistic tendencies