Most early Irish music is modal, in other words the tune is all. What is important is what you hear, not what you believe you should be playing.

The accompaniment that is played is played as the tune decrees, and the tune will often trip through chords rapidly as though they were melody notes. This example feels a bit like that.

Russell, modal music can include chord changes. We tend to focus on the chords and the note is less important. For instance in bluegrass and blues the chord pattern is all - you can almost smell where the tune is going to end up. This wouldn't be the case with modal forms. It's a key reason why Irish music sounds Irish.

There are interminable debates over how to accompany Irish music - check this one out about the problems of playing guitar in Irish trad music http://www.thesession.org/discussions/d … mment84638 .

We tend to speak in terms of triads when we talk about chords.  The major and the minors.   But the same rules apply for 7ths as well.  While the triad appropriate for the V is a major chord, the 7th chord appropriate for the V is a dominant 7.

Its still that good old I IV V progression, but in this case, it's done with 7ths rather than triads.

how often are chords taken from the key ?

well, that depends on your music taste

if you have a pop sensibility then most songs are going to stick fairly rigorously to the  expected chords

blues and blues rock have there own variations (eg dominant sevenths and a couple of others)  but don't otherwise depart much from the formulas

however Jazz and many 'experimental'  musicians tend to play fast  and loose with the rules (sometimes in the pursuit of what is a fairly atonal noise).

usually when I mess around with chord progressions I stick to the key. i have sometimes  thought of adding non key chords however in my experience theres plenty of scope for tunesmithing within the key.

j

Theory is not so strict as we all might think. It is simply a way to describe what we are doing musically in a common language.

How do we get away from a "strict" key? You can modulate (essentially changing keys) within a song, and you can also borrow related chords into your progression.

In the Beatles' I Feel Fine (key of G), The chorus runs G - Bm - C - D on the first line, and G-Bm - Am - D on the second. Since the Am is the relative minor of C, we say the chord is borrowed.

Am is in key for G major.  It's the II.  Modulation and borrowing are all well and good, but I Feel Fine, is actually in G, and those chords, well, fit fine. 

How do we get away from a "strict" key? You can modulate (essentially changing keys) within a song, and you can also borrow related chords into your progression.

In the Beatles' I Feel Fine (key of G), The chorus runs G - Bm - C - D on the first line, and G-Bm - Am - D on the second. Since the Am is the relative minor of C, we say the chord is borrowed.

In Cry Baby Cry, the verse runs down as Em - EmM7 - Em7 - Em6 and lands on C7. That C7 (which we have all head a million times) will never sound so "twangy" to your ear as it does coming at the end of that Em run, falling off the C# in the Em6. (Try substituting a C#°7 for the Em6... same notes: E-G-B-C#. )

http://www.youtube.com/watch?v=O49gt5f0 … mp;index=5

You have to scroll to about 40 seconds in to get to the song (ignore the propaganda).

I hear D-C-A and then G-C-A.  But I hear them all as major, and one of the chords would have to be minor (I think it's in C major?).

An answer to this question would be greatly appreciated!  Thx!