The purpose of 'the key'

[Horberg]

I am a self-taught guitarrist and trumpetplayer, and I am curious to why the key of a tune at a specific place is important when improvising. When I improvise I play the major scale to any major chord, minor scale to minor, mixolydian for Dom7 chords and so on. Why should I pay attention to the key? Am I missing out on something important? Thank you for any help

[jazz oud]

Because the key is how the chords work and relate to one another.

A major chord that is IVmaj7 will usually sound better with a #4 in the scale (as in the key). A dominant 7 chord that is III7 will usually sound better with b9 and b13 (as in the key). Without understanding the key, you don't know when you are leaving the key. If you don't know when you are leaving the key, then you are not in control of your improvisations.

[dogbite]

i agree. it's all about context. a chord functioning as a III7 (or V7/vi) will behave very differently than a V7 because of its relationship to the tonal center and the other tones of the scale, thus accounting for many of the commonly found alterations (for example on III7) such as b9 and #5 (b6 or b13).

horberg's approach is valid, but represents one aspect of how the chord itself (local, vertical) fits in terms of the surrounding tones of a scale or tonality (global, horizontal).

[Horberg]

Thanks! That help a lot! All I have to learn now is to figure out how to determine the key...

[Mariotte]

I believe that the easiest way to determining a key is doing so aurally, or following some steps in order to deduce it theoricaly.

For most songs (which usually are "tonal"), the global key is base around the one note you would go in order to finishing the song at any given point. That's the key.

(usually the song ends in the firts degree chord of the key, so there you have a theorycall aproach).

Listen to any song and try to sing an ascending fourth interval that hit this ending note. This is a strong tonal resolution. Some songs like "tangos" usually end up with this melodic movement, which is used as the movement of the bass: V-I (sing it "chan chan", if you have heard some Tango, or check it up). BTW, V-I is the core of tonal musical. In the key of C, you would sing "g-c" (being g the lower note)

So thats they key... as I said, if you are proficient in detecting it, you can stop the song any time and "make it end".

I talked about "global key". From there, you will find more complexes tunes, in which you could find segment that modulate to another (temporal) key. This is not that usual in, for example, rock songs, nor in many popular songs, but there are songs with this areas.

In jazz, a lots of II-V chords that belongs to another key usually serve as trampoline for really fast modulations (or not so fast), to those keys.

If you think in the global key as a strong gravity force, you can imagine it like our Sun. When you modulate (make your space ship jump with II-V's) you aproach another planet, and feel his gravity also. But this planet and you are still affected by the sun's gravity.

I mean, there are some classical music pieces that makes really simple modulations, for example for about four bars. Lets say, you start in C, but suddendly the composers adds a F# in the C section, generating a dominant chord, D7, that wants to go to G. So you starts a new section, and now G is the firts degree. Usually the composer return to C briefly, but also he can go to another "fellow key". If he wants to return to C, he would implied a G7, and hit the f instead of the f#.

Althought is a "temporal modulation" the composer state clearly that we are now in this new key, so until he found a way out you ear will think the song now is in G (but somewhere in your mind you can recall the original key).

(in the cosmonautic metaphore, here you have jump near near a big planet with huge mass, away from the Sun, but still the gravity force of the big star is affecting everything... you can also say, forget this, and try to aply more force and go anywhere in the universe, and jump end up far off your original key)

I hope I'm not messing this explanation!!! I will add something:

THEN you also have MODAL TUNES. The share also the notions of "being in the key that finish the song", and the V-I melodic movement is not that strong, althought it exist.

TL;DR (haha): try to finish the song in your head, you will have the key, also you can check out the last chord.

[engelbach]

Originally Posted by Horberg

Thanks! That help a lot! All I have to learn now is to figure out how to determine the key...

Two ways to begin.

1. Look at the key signature on the score.

or

2. Listen and determine what note and chord would finalize a cadence.

[Mariotte]

Originally Posted by engelbach

Two ways to begin.

1. Look at the key signature on the score.

or

2. Listen and determine what note and chord would finalize a cadence.

The key signature, althouth a great hint, could be confusing, as you would not know by it if the song is in the major key or in the relative minor of that key signature. So you have to check out how the song ends, and there you usually have the key (unless the song have some special coda).

Also, with modal tunes, the one making the transcription can choose to use the ionian (major) key signature related to the modal key. For example, if the song is in G mixolydian, F lydian or D dorian, the transcriptor could use the C major key signature.

Addicionaly, I THINK (I can't remember any by I believe I seen that) certain transcriptors (and composers) just don't use the key signature, they just use the alteration whenever they need them to appear.

So, the key signature by itself doesnt give you all the information (I would change the OR of your post for an AND).

Further, I believe that is great to be able to detect the key by the score and also aurally.

(It amazes me that some classic trained musician have a hard time finding out the key of a song!!! I have witnessed this.)

[engelbach]

Originally Posted by Mariotte

The key signature, althouth a great hint, could be confusing, as you would not know by it if the song is in the major key or in the relative minor of that key signature. So you have to check out how the song ends, and there you usually have the key (unless the song have some special coda).

Also, with modal tunes, the one making the transcription can choose to use the ionian (major) key signature related to the modal key. For example, if the song is in G mixolydian, F lydian or D dorian, the transcriptor could use the C major key signature.

Addicionaly, I THINK (I can't remember any by I believe I seen that) certain transcriptors (and composers) just don't use the key signature, they just use the alteration whenever they need them to appear.

So, the key signature by itself doesnt give you all the information (I would change the OR of your post for an AND).

Further, I believe that is great to be able to detect the key by the score and also aurally.

(It amazes me that some classic trained musician have a hard time finding out the key of a song!!! I have witnessed this.)

As I said, those are two ways to begin.

[Mariotte]

Ah, you're right

[alez]

On my transcriptions, I tend to write the key right next to the name of the song, chiefly because I use whatever key signature I think fits the MELODY best. Standard blues and soul often get mixolydian signature, even a dorian one if the major third is never used on the melody, no matter all chords are "7" (major). I think maybe other people do the same, which would mean there's no way to tell what the key is from the key signature, really...

[jazz oud]

Originally Posted by alez

On my transcriptions, I tend to write the key right next to the name of the song, chiefly because I use whatever key signature I think fits the MELODY best. Standard blues and soul often get mixolydian signature, even a dorian one if the major third is never used on the melody, no matter all chords are "7" (major). I think maybe other people do the same, which would mean there's no way to tell what the key is from the key signature, really...

This is not standard practice, and since notation is by design supposed to reflect common standards, you really should use the major or minor key signature that fits rather than a modal key signature (unless it actually is a modal tune), or none at all. It makes more sense from an aural standpoint, as well, IMO.

[alez]

Originally Posted by jazz oud

This is not standard practice, and since notation is by design supposed to reflect common standards, you really should use the major or minor key signature that fits rather than a modal key signature (unless it actually is a modal tune), or none at all. It makes more sense from an aural standpoint, as well, IMO.

That's interesting, because I was actually taught that mixolydian was the most "proper" signature for standard blues harmony in particular (although it was alright to use major). The guy who said that (my teacher at the time) is an accomplished musician (performer, author, arranger, leader, director) as well as an educator, and he learnt his stuff at the Berklee School of Music... so if you reckon it's not standard practice, maybe this guy is just a bit eccentric on that particular thing?

[jazz oud]

Well, a "mixolydian key signature" sort of makes sense, but not really. Except for actual modal music, jazz has enough going on harmonically that it doesn't make sense to pick a non-tonal key signature over the standard one absent an extremely compelling reason.

Rather than relying on my opinion or your teacher's opinion, check it against reality: if you check any published music, you will see that using the regular key signature is the norm. I just looked at the first few books on my shelf: The Standards Real Book, Sammy Nestico's "Complete Arranger", The Thelonious Monk Fake Book, and Jazzology. In every case, the blues is notated with the regular major key signature.

Some people use all kinds of weird signatures, but since the purpose of notation is communication, it doesn't make sense to be idiosyncratic.

From a logical standpoint, consider:

In a jazz context, a typical Bb blues really uses the following scale:

Bb C Db D Eb E F G Ab A

That's 10 notes, really everything except b2 and b6 (not that those aren't used at all, but the rest is pretty much a given).

Since the Bebop blues heads pretty obviously make more sense with a tonal key signature, and it makes more sense to use the same key signature for any blues in a particular key (i.e., F blues should always have the same key signature), there is really no good reason to use a mixolydian key signature. All you're doing is giving a preference to b7 over 7, when most blues will use both anyway. It's not like blues is in mixolydian, it has a kind of major/minor interchange.

The other advantage of using a regular key signature is that it makes clearer how the blues is deviating from traditional major/minor tonality, which is how we tend to actually hear it.

[engelbach]

Originally Posted by alez

On my transcriptions, I tend to write the key right next to the name of the song, chiefly because I use whatever key signature I think fits the MELODY best. Standard blues and soul often get mixolydian signature, even a dorian one if the major third is never used on the melody, no matter all chords are "7" (major). I think maybe other people do the same, which would mean there's no way to tell what the key is from the key signature, really...

Hola Alez,

There is music that deviates from the standard to the point where the key signature is meaningless.

And Bela Bartok, for one, sometimes invented his own key signatures to indicate the unusual modality of many of his pieces.

But since (playing the hyperbolic percentage game) perhaps 99.99% of Western music has a standard way of using the key signature, the expectation that one can tell the key from it is, well, rather high.

Cheers,
Jer

[alez]

I very much appreciate your posts, I learn a lot from them.

Well, then clearly it's a case of this guy being eccentric about that.

So this is day zero for me to start using tonal key signatures only.

Originally Posted by jazz oud

All you're doing is giving a preference to b7 over 7, when most blues will use both anyway.

I suppose it's kind of treating the key's 7th like it's done in minor: minor 7th on the signature, raise it for V7 (typically). From that perspective, the result has more similarity to a tonal approach than using a major signature.

Originally Posted by jazz oud

It's not like blues is in mixolydian, it has a kind of major/minor interchange.

Understood. I tend to see the key signature as a way of having tidier sheet music (i.e. minimize the number of written accidentals), hence my idea (backed by my teacher's comment, I thought at the time) that reflecting the melody should be the way to go...

Thanks guys, that's one more I've just learnt how to do correctly!