How weird would it be to end a song in a different chord than the key of the song...

...or a related chord? I know this is a really generic question but I have a song that is in Dmaj7 and because of an odd bridge needs to end in Fmaj7. Would that be subliminally jarring?

Do it. Post it. We'll let you know.

it all depends how it leads up to the F from D. If you play a C right before the F or even Eb Maj or E dim, it won't said bad probably.

Songs and other musical compositions perform all sorts of modulations. As suggested above, if it works, it works.

Getting it to work might take some tinkering, of course.

It's a Cm...

I think it'll work just fine. That Fmaj7 is a lot like a Dm9 without the root. Sometimes it's cool to end a song in a major key with a minor chord. When it's done the other way around, minor song ending on a major chord (song in Cm ending on C), it's called a Picardy third. There's probably a fancy-pants name for what the other way around, but I don't know it. Sometimes I throw in a minor chord ending like this to add suspense or mystery or to give the tune an unresolved feeling. Works really nice with m6, too.

btw, I think you meant that your song was in D major, not Dmaj7.

I've got a tune here in C that ends on A6/F#m:

http://soundclick.com/share.cfm?id=9406919

Tho technically there's a transitional E7 chord, which is used throughout the song.

THE CHICKEN MONKEY GETS IT DONE!

What makes you think that?!?

The notes of the chord are D A Db Gb. I've always called this chord Dmaj7 but maybe thats wrong?

That's the chord, not the key.

There is no such thing as the key of Dmaj7, but there is a key of D major. Also, you've spelled Dmaj7 incorrectly: D F# A C#.

Yeah, when I read the title of the OP I was thinking of this kind of 6th chord ending (which is VERY common in 50's-60's music - check George Harrison's final chord on any of the early Beatles songs), but the actual question seems to be about a key change inside the song (since he mentions the key of the bridge) which is also VERY common in Great American Songbook/Jazz Standards music (but slightly different from what you have executed, where the verse and chorus share the same key).

I guess this is a theory issue, and that's fine and all but when I'm talking to other musicians that I play in bands with and I tell them a song is in the key of Dmaj7 they know EXACTLY what I mean. If I told them Dmajor they would play D A D F# which would be incorrect for our purposes.

Yeah, as long as you get your general point across the details don't matter much.

Yeah, the audience doesn't know whether a song is in Dmaj7 or R- and doesn't care...

not too weird at all - classical music theory even has a name for these (at least the ones coming from the Dominant 7, which strongly suggests a tonic resolution ) -- "irregular resolutions"

One thing to consider - you mentioned having to change b/c of a weird bridge. It's possible you could have implied a key change and the tonic has actually moved on you from the beginning.

irregular resolutions (like a "deceptive cadence") can lead to this sense of incompleteness or urgency at the end of a tune, that you can use to dramatic effect.

My apologies - I've heard it used many many times, but i'm having the "that guy" character actor brain fart right now.

you know "Oh look, it's that guy, that charter actor! man, he's in everything...I mean I can't name a single thing right now, but he's in everything!"

so totally nothing wrong with it, at if you aren't coming of a dominant anyway, you won't have that super-duper "authentic cadence" suggestion to the listener that feels "unresolved".

Think about it like the end of dramatic movies where the end isn't so much James bond has dispatched the baddies and gets the girl and everything is wrapped up all pretty-like, but where the protagonist is left with a tough decision or a "where do I go from now" sense, or regret or whatever....Those endings where it isn't so much "and they lived happily ever after"

Yes, I think that is correct. The way the pattern progresses it sounds resolved to end in Fmaj7. It doesn't 'sound' weird, it sounds right.