Cadences
 

There are a few different types of cadences:

Perfect authentic cadence-
is when a progression ends with a V-I, whereas the V and I chord are root chords with no inversions, and the I chord has the tonic note doubled in the soprano line.

Imperfect authentic cadence-
Likewise, is when a progression ends with a V-I, but can be inversions and/or there doesn't have to be a doubled tonic note in the soprano line of the I chord.

Half cadence-
is when it ends with a V, hence the "half." Usually it is a root chord, but I guess you could end with an inverted V.

Plagel cadence-
is when it ends with a IV-I chord along with most of the same rules for the PAC. These cadences are the "A-men" of most church plainchants.

Imperfect Plagel cadence-
Like the IAC, but the fact that the VI-I chords can be inverted and such.

The plagel half cadence speaks for itself,
and then there is something called a Picardy 3rd cadence-
which is when you end a major keyed song with a minored tonic. For example: when you are in a piece of C major, and you end with a V-I chord, but the I chord is that of the relative minor key. Kinda weird and rarely used but really cool.

do you think you can go a little more in depth with this? like explain what cadences are, how they are used and be a little more detailed in your description of the cadences? that would be highly appreciated. thanks

when you say end in V-I do you meen end with a V chord then a I chord? or end with them at the same time?

the amen cadence was added to the original chorales by many bishops and such. they were later removed mostly for the preservation of the original piece

@Demon, it would be a root position V followed by a root position I, with the tonic in the soprano line. (PAC)

@transient, eh? heh, I would think that cadences were part of the original chorale....why would they take the end off of a song to preserve the original? THat doesn't make much sense to me....

a-men was tacked on at the end of most chorales

is the tonic, the I chord, or the root note of the I chord?

It's the latter-tonic is the root of a I chord of the key signature.

He pretty much went as in depth as one can go when it comes to cadences. There's nothing more anyone can really add.

There's two more cadences that I can think of, and one of them is the deceptive cadence.
The Deceptive Cadence is V- ?. The piece builds up to the V, then when the ear expects to hear the I, it instead goes to another chord, most of the time that chord being a vi.

The other cadence is the leading-tone Imperfect Authentic Cadence. What this is, it's an inverted V7 to I. The other way this can be accomplished is a vii (dim) to I.

Isn't there also an 'interrupted' and 'imperfect', where are the song sounds like its finishing but then just starts up again or just finishes with an incomplete sound respectively.

That would be a half cadence. The progression is ? to V. It's pretty much any chord to the V chord.

Try this:
http://www.dolmetsch.com/musictheory22.htm

OK, but what about songs that just finish without reference to their whereabouts in the key? Like, for example, The Stillborn One by Necrophagist?

Is that the cadence at the end I'm assuming? Because if it is, then that's a half Cadence. It's ending on an E Major chord, which is the V of A Minor.

EDIT: Sorry, I was thinking about this question once I had left the computer. Now that I look back at the piece you gave me, I believe the last chord before the Cadence could be a iv chord. The part that goes



I believe the chord before the V could be analysed as a D minor chord with the E being a passing tone to the 3rd of the chord.