Full Version: How Can I Tell What Key A Song Is In?
Andrew Cockburn
Finding the Key of a Song

Ok, so you have a killer MP3 of some band you have downloaded that you want to Jam to, or you have an amazing tab that you want to develop ideas from, or maybe even a piece of music that you want to work with. Before you can do anything, you need to figure out the key that the song is in so that you can apply all of your knowledge about scales etc to figure out which notes to play. In this lesson we’ll try and figure out some ways to do this. There is no substitute for experience with this, and there isn’t always a failsafe formula, but a little knowledge can go a long way towards helping you with this. We’ll look at getting the key from Music, tablature, and also by ear, and by example.

Sheet Music

So lets take the easiest case first – you have some sheet music for the song you are interested in. I am calling this the easiest because in this case there is a failsafe formula you can use. Of course, if you don’t read music this may not seem easy to you … If there is any interest, maybe I will write a future series on music notation. If this isn’t of interest to you, just skip ahead to the next section on tablature.

If you read music, you probably already know about key signatures. The key signature is written as a group of symbols at the beginning of the piece of music, listing either a number of sharps ( # ) or flats ( b ). The sharps and flats are always listed in a particular order, which is determined by the Circle of Fifths, although that isn’t important for this exercise (note to self - write a Circle of Fifths lesson!)

Here are a couple of examples:

The key of C – no sharps or flats

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The key of E – four sharps

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The key of B flat – 2 flats

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Now, assuming you understand the notes on the staves above you can very quickly determine the key using the following simple rules. (If you don’t know the notes why are you looking at sheet music anyway?  )

1. If there are no sharps or flats the key is C.

2. If there are sharps, look at the stave line that the last sharp symbol is placed on, and go up 1 degree of the scale. In the example above, we have 4 sharps, F#, C#, G# and D# (again, these are derived using the circle of fifths). The last sharp is D# - one degree up from that is E. Another way to put this is that this sharp sign gives you the 7th of the scale. One up from that is the 8th, or root, giving you your key. So the example above is in the key of E just as we thought.

3. If there are flats, look at the stave line that the last symbol is on and go down 4 degrees in the scale, or to put it another way, the last flat sign gives you the 4th of the scale. In the example above we have Bb and Eb – 4 degrees down from Eb is Bb, which is the key (Eb-D-C-Bb in sequence). This rule isn’t particularly helpful if you are struggling to work out the key, and there is actually also an easier trick for flats that I prefer. This comes out of the circle of fifths and the fact that we are going backwards (I really need to write that circle of fifths lesson!), Don’t worry about the details for now but believe me when I say that each flat in a key signature is separated by 4 degrees, so you can look at the flat immediately before the last one which will give you the exact key signature. This doesn’t work for one flat, so you just need to remember that one flat is the key of F. In our example, the last but one flat was Bb, which is our key.

So, using the rules above and a sheet of music you can immediately deduce the key … apart from one subtlety. If you have read my lesson on relative minors, you will know that each major key has a related minor key. They are related by virtue of the fact that they share the same key signature. So you can narrow it down to 2 possibilities using the key signature, after that, you need to decide if it is major or minor – see later in the “by example” section.

Tablature

So much for exact methods – it gets a little harder from now on. Guitar tabs are an informative guitar-friendly way of putting riffs down, but they generally don’t include as much information as sheet music. In particular they miss timing and key information, often relying on backing tracks and descriptions and analysis to support them – if you are lucky the description will give you the key. Also, a lot of tabs published in magazines include the key at the top of the tab. So if you have a tab without the key how do you tell what key it is in? Well at least you have the notes, which is a good start. One method is to write down all of the notes in a bar or two and compare them to scales that you know. If you can pick out 8 different notes you stand a good chance of figuring it out, if you only have two you might be stuck (in that case I suggest you listen to the backing track if there is one and use the “by example” method). If you pick out 8 notes and for instance they are A,B,C,D,E,F and G that gives you some strong clues. The first 2 options are the key of C and the key of A minor – probably the most likely possibilities. I worked this out by ordering the notes and comparing them to the notes in various major scales (its useful to have a reference somewhere for this, such as the Guitar Grimoire).

Other possibilities include the various modes of the C Major scale. In roughly diminishing order of likely hood these would be:

• A Aeolian (the same as the A minor above),
• F Lydian, G Mixolydian
• D Dorian, E Phrygian
• B Locrian

If you suspect modes are in use, experience helps you to figure this out, in particular, check out the chord that is being played as it will likely give you a clue to the mode – for instance Em or Em7 would point towards a Phrygian scale rather than a standard major.

Of course you may run into some very complex scales that aren’t easy to spot by looking at the notes, or even someone is just plain “cheating” in which the song is being played chromatically or without reference to a particular scale. Once again, knowing the backing chords will help you here.

By Ear

Some people are able to listen to a piece of music and instantly tell what key it is in. How do they do this? Well, there are two ways. The first is called perfect pitch. It refers to the ability to hear a note and instantly know what that note is. It is generally believed that some lucky people are born with this ability, but others argue that it is possible to acquire it through training. I am somewhere between the two schools of thought – I believe that a good ear can be trained to perfect pitch. Through experience I can usually get within a semitone of an E when tuning a guitar without a tuner, but not reliably enough to dispense with the tuner altogether!

In either case, you need a certain amount of musical experience to deduce the key even if you do have perfect pitch, and people who can do this will be unconsciously using the techniques I describe shortly in the “by example” section.

The second way I am going to call “by character” – I don’t know if there is an official name for this, but experienced musicians can usually tell from the selection of notes in a chord and the particular resonances in a piece of music exactly what chords are being played. This works best for guitar players listening to guitar pieces. For instance, a chord of C to me sounds very different to a chord of G, even when I don’t know what it is. It gets harder when the chords move away from open strings. This technique is definitely more based on experience than having perfect pitch. Once again, when you have the chords you would apply the techniques below to figure out the key. You can train yourself to get better at this by playing various chords and listening what they sound like and identifying the root notes.

By Example

This is the method that probably most of you will be using at least to start with, especially when trying to figure out the key of your guitar hero’s solo. The key to this (pun intended!) is to figure out what chords are being played. To do this, pick up your guitar and try to identify the root notes of the chords by playing notes up and down your E string until you find a match. Your chord listening training above will come in handy, because you are always looking for the root note of the chord, not one of the additional notes. By this I mean that for instance a chord of C major has the notes C,E and G in it. C is the root here. When you are trying to pick a C chord out of a piece of music you are listening to, you need to identify the C note, not either of the others or you will be off in the wrong direction!

For each chord you identify, you need to decide if it is in the Major or Minor family – again, there is no rule for this, you need to train your ear to understand the difference. A starting point is that major chords sound happy, and minor chords sound sad, but you need to try this for yourself with chords you know.

Now you have a list of chords, it gets even hazier. You next need to try and figure out what the tonic chord is. That’s a fancy way of saying the root chord or 1st of the scale. In music there is always a tension and movement between different chords in the song, such that when you get to the tonic or root chord, there is a feeling of resolution, or being back on home ground. Other chords lead you off in various tonal directions, but the end of the journey is almost always back to the tonic. The tonic may or may not be the first or last chord played, but there is usually a sense of completion when you get there. If you don’t know what I am talking about you need to train your ear some more to pick this up! In fact, most often, the chord a song ends on is the tonic which can be a good clue. But, if the songs ends with an uneasy feeling of something missing it could be because it isn’t ending on the tonic, so be careful!

When you have identified the tonic, be it major or minor, you are pretty much there – the rest of the chords may help to confirm it as there are usually families of chords played in a particular key that have root notes that match the scale in question. For example, the key of C/Am has the following characteristic chords:

C, Dm, Em F, G, Am, Bdim

These are the chords that make use of the notes in the scale they belong to. If you see that the chords in the piece you are working on include these, or variants of them, it is a good sign that you are in that key. However, these chords are really just a jumping off point, and don’t take account of the fact that there may be sudden key changes in the song, or the composer may just plain and simple ignore the rules and throw in some random chord because it sounds cool. As with all theory, this is just a framework to hang your creativity on, it isn’t a straitjacket that constrains you.

Well that’s about it. In all of this there is no substitute for experience and ear training, and no guarantees you got it right (you'll figure that out when your scales sound wrong against the piece in question), but practice a lot and soon you’ll wonder what all the fuss is about – can’t anyone tell its in that key?
mattacuk
Another fantatstic Lesson. I really wanted to know how the ### and flat symbols worked and i now have a good basic idea. Reading music is definatly the way foward!! I also like the way of useing musical notation to figure out what key something is in

I wait in anticipation for your musical notation lesson!
Igorrr
Great lesson, especially the info on the last # being the 7th was great info...

Actually I think there are some tricks to make it even easier:

1.) Listen to the last note/chord of the song.
In most pop / rock songs the songs will end on the root chord or note the song is in.
Especially if you feel that the song has reached a conclusion and closes with that last note/chord.
If it ends in suspense than it is not the root chord/note.

2.) By Ear with instrument
In many cases most people, even not being musically trained, can sing the root note of a song.
Sing the root note when listening to a song and try to move up a scale on that singing (restart if you sing a note that sounds bad)
Once it sounds right search these notes on the guitar (or any other instrument). From the resulting scale you can determine what key you are in.

This only works with songs though that don't go through X key changes or progressions.
Kevin98497
hey andrew, hmm, the music staff is in the wrong order.... it is cleff, then time signature and then the sharpes und flat

youd loose 2 points in an exam for that mistake =P
Andrew Cockburn
QUOTE (kevin-riff-after-riff @ May 7 2007, 05:51 PM)
hey andrew, hmm, the music staff is in the wrong order.... it is cleff, then time signature and then the sharpes und flat

youd loose 2 points in an exam for that mistake =P

Heh - you can blame Guitar Pro for that
Igorrr
Was in doubt (never really cared) and by randomly searching scores in google all were with Cleff / key / time.
And as far as I know the scores in Cubase as well.
Xranthoius
Man, I cannot believe I read the whole thing, it kept me going awesome job Andrew, and thanks!!!
shammy
yeah me too, I have read the whole lesson completely and have toyed with theory in the past. Hopefully I can stick with it this time. I would love to be able to just pick up a peice of sheet music and have a go at it with my guitar. I always end up getting lazy and look at tabs.

Nice lesson Andrew!!!
Philippe
Thanks a lot for this explanation, but I'm still confused. In particular, what is the exact definition of a key?

I think I understand what a signature key is, but I'm not quite sure about a key. My understanding is that keys and signature keys are (related but) different concepts. Signature key is a notational concept, whereas key is a musical concept.

By choosing an appropriate key signature, one can avoid (or limitate) the use of # and b in the sheet music. This is due to the fact that:
1 - most pieces of music are built over the notes of some major scale
2 - for any root note, we can write the corresponding major scale with the notes A B C D E F G + some alterations (either b or #)
In conclusion, the key signature is the major scale that contains the notes used in the song (or at least, the one that offers the best approximation).

On the other hand, the key gives the musical flavor of the song. That's where I don't know the definition.
I understood that in most cases, the key can be determined by the key signature + by analyzing the chord progression to see which one is the "home" chord. For instance, if the key signature is C, and the home chord is D, the key is "D dorian"? if it's A, it is "A minor" and so on. Is that correct?

And what if the song is not based on a relative mode of a major scale? does it have a key anyway? For instance, is "A Phrygian Dominant" a proper key?

Thanks,
Philippe
Andrew Cockburn
Hi Philippe,

Some very good questions there!

Key signatures evolved to work along with music commonly played at the time - and as you have said, are based on the major scale (and their modes). At the same time, many scales are in use in western and other music. The trick is to not mix up scales and keys.

Key signatures are merely a notational device that make it easier to express the notes in a piece.

A Key is pretty much as you said an approximation to the set of notes you want to use, based on the major scale and its modes.

A scale is the exact palette of notes you are working with at a particular time.

So given the above, keys are generally expressed as a root note, and sometimes a note of the mode in use.

A Major is a key, so is its relative minor F# minor - after major and minor it is rare to see other modes referred to, even though they actually share the same key signature. If you were working in B Dorian for instance, the same key signature would apply, and it might have the notation "Dorian" at the top to tip you off, also the chords in use would be a clue.

A Phrygian Dominant however, is not a key, its a scale. In order to notate this, you would need to pick the major scale or mode closest to it, in this case probably A minor, then use accidentals for the b2 and Natural 3.
Philippe
Slammer
I have a quick question...

Sorry it may be a really dumb one but.

I'm starting to get into theory alot now, and one thing I was wondering is In chord Progressions do they have to start with the Root Chord of whatever key they are in?

Like for Example, If I had a Chord Progression of Verse: F-C-G-C-F-C-Dm-G. and Chorus: Am-Em-F-C-F-C-G-C.

Would the key of the song be C? Even though the song starts in F, from what I've learned in Andrew's "Chords for Scales" lesson, all those chords above are in the Key of C.

Sorry for the Long Question but it's something I've been wondering about for a few days. And if Andrew or Someone Knowledgeble could answer, It would help alot

Thanks
Muris Varajic
Yeah,it IS in Key of C Slam.
You don't have to start with C chord or to end with it
but you still feel "relief" when laying a bit on C chord,
that's why it's root/home chord.
Slammer
Hey Thanks Alot Muris.

That Really Helped me alot... and Now I understand alot more than before.

Thanks again
Muris Varajic
QUOTE (Slammer @ Jan 12 2008, 03:30 AM)
Hey Thanks Alot Muris.

That Really Helped me alot... and Now I understand alot more than before.

Thanks again

You're welcome
Ben Howell
Great lesson Andrew, very well explained.

-Ben
Andrew Cockburn
Thanks Ben
FretDancer69
QUOTE (Muris @ Jan 11 2008, 06:56 PM)
Yeah,it IS in Key of C Slam.
You don't have to start with C chord or to end with it
but you still feel "relief" when laying a bit on C chord,
that's why it's root/home chord.

but isnt that "relief" something that could vary between people...? this is what confuses me about identifying keys in chord progressions, i dont know which chord is the one that gives the "relief"...
Muris Varajic
QUOTE (FretDancer69 @ Jan 17 2008, 03:32 AM)
but isnt that "relief" something that could vary between people...? this is what confuses me about identifying keys in chord progressions, i dont know which chord is the one that gives the "relief"...

Well you have to feel it but usually it's chord on start or end of something.
Usually but not always.
It's not hard to feel it actually,you just have to play more music and understand root better,
comes naturally after a while indeed.
FretDancer69
QUOTE (Muris @ Jan 16 2008, 09:01 PM)
Well you have to feel it but usually it's chord on start or end of something.
Usually but not always.
It's not hard to feel it actually,you just have to play more music and understand root better,
comes naturally after a while indeed.

thanks. I understand what you mean. Ill keep studying.
Andrew Cockburn
Hey Fret, I sympathise with your question - its almost impossible to describe this, but you will know it when you start to feel it. If you don't know it you need to practice some more - fortunately practicing this is fun - you just need to listen to a lot of music, and think a little about it while you are doing so.

Pick a song, listen to it as usual, and after each chord change, ask yourself "did I get somewhere with this change, or am I still moving to somewhere else". If there is still a feeling that you need to move on, you are not on the root. AFter a while you should be able to pick out the chord that is the root. When you can do this, start listening to songs that you know the key and chords of and check that you are right.

That's the best explanation I can give you - keep working on it
FretDancer69
thanks andrew, i do listen to alot of music, almost constantly when im not at school, but the problem is, i dont know what are the names of the chords that are played, so that makes it harder, but i understasnd how its done, its just a matter of time ill guess, ill keep working on this for sure.
FretDancer69
Hey Andrew, i was re-reading this lesson again and i found out something that confuses me, it is the following:

QUOTE
2. If there are sharps, look at the stave line that the last sharp symbol is placed on, and go up 1 degree of the scale. In the example above, we have 4 sharps, F#, C#, G# and D# (again, these are derived using the circle of fifths). The last sharp is D# - one degree up from that is E. Another way to put this is that this sharp sign gives you the 7th of the scale. One up from that is the 8th, or root, giving you your key. So the example above is in the key of E just as we thought.

Ok, so you say 1 Degree. But doesent D# to E means a Semitone? Im confused, but then again, the statement that i underlined above contradicts my doubt, Yes, the next degree from the 7th would be the Octave but i dont understand how can D# to E be one degree?

EDIT: nevermind Andew, i figured it out, i cant believe how silly i am, sorry for wasting your time.

i was looking at it in a different, way: the order of the notes on the fretboard, instead of the degrees of the E Major scale. Jeez im going nuts!
DeepRoots
QUOTE (FretDancer69 @ Feb 4 2008, 05:05 AM)
Jeez im going nuts!

Dont be so hard on yourself man! We all have mental problems blocks

There really isnt a waste of anyones time if you dont yet undertand something...

Glad you figured it out tho
Andrew Cockburn
QUOTE (DeepRoots @ Feb 4 2008, 12:14 AM)
Dont be so hard on yourself man! We all have mental problems blocks

There really isnt a waste of anyones time if you dont yet undertand something...

Glad you figured it out tho

Thanks Deep - thats a great point - if you hadn;t figured it out we would have been happy to help you with it
gudinho
Andrew, great article I never had this Music theory as clear as now, and about the subject I have a kind of method to figure out the key of a song, and sometimes works with the chords as well, I try to stick to the bass lines 'cause they 're much easier to follow, this is not 100% effective some bassist do a lot of movements, but works with some tunes and with some parts of the song. Does it have any sense at all?
Andrew Cockburn
Sure - thats a good point - a lot of the time the bass is playing around the root notes of the chords so that will help you figure them out
-Zion-
hi Andrew.

I have a question about finding the key in a song.
Lets say the song has this chord progression: C, G, Am, Em
it's a fairly simple chord progression, but i just want to make sure i understand correctly..

Now i have this Major scale chart, and plotting the chords into it, i have now narrowed the list of possible keys down to three.. C, F and G.

Is this a correct way of figuring out the key of a song? it seems to make sense to me, but i just want to make sure..

And another question: What determines whether the key is major or minor??
i dont suppose that all chords in the progression should be minor chords.

Thank you very much.
wrk
Andrew can explain this maybe more clearly, but one thing i noticed in your approach, so maybe it's helpful.

You should check the other notes of each chord as well:

C major - C, E, G
G major - G, B, D
Am - A, C, E
Em - E, G, B

In your diagram you have marked the F major scale as an possible option, but F major has a Bb on the 4th. Which would not really fit with the G and Em chord.

To choose between the C or G major scale is depending on which chord is the main focus i guess.

Maybe it would help you if you expand your Diagram with the complete chord on each degree.

-Zion-
Hi wrk and thank you for your input
So i have been a little too fast.. Instead of plotting in the chords directly i should plot in the notes of the chord??

C major - C, E, G
G major - G, B, D
Am - A, C, E
Em - E, G, B

these chords gives me these notes: C D E G A B narrowing it to two keys C and G?
however, the C contains an F note and the G an F#, so.. .. well.. i dont know..
DeepRoots
You seem to have analysed it well enough
Next id say try using your ear- try to identify which chord in this progression sounds like...home...finished- this is then your answer

To me while i play through this progression once and then end on anothe C major- everything sounds finished and resolved nicely- so to me i guess it's C major.

The next step i would reccomend is to record and loop the backing chords and then play either a C major or G major scale over them and see which you think sounds better- remember to lean on the root note of the scale alot for a better comparison.

I'd say that generally if i have a progression that could fit in to two keys i listen for the chord that resolves it which is (most of the time, not 100% of the time) the first in the progression.
wrk
QUOTE (-Zion- @ Jul 30 2008, 10:47 AM)
these chords gives me these notes: C D E G A B narrowing it to two keys C and G?
however, the C contains an F note and the G an F#, so.. .. well.. i dont know..

As you said, the difference between C and G major scale is the F or F#.
The notes of your chord (1st, 3rd, 5th) progress does not include an F or F# somewhere... by now

As an add on DR's advice ... when you play/record your progression try to add the 7th (especially on the G major chord) and you will quickly notice in which key you are.

-Zion-
QUOTE (DeepRoots @ Jul 30 2008, 11:00 AM)
You seem to have analysed it well enough
Next id say try using your ear- try to identify which chord in this progression sounds like...home...finished- this is then your answer

To me while i play through this progression once and then end on anothe C major- everything sounds finished and resolved nicely- so to me i guess it's C major.

The next step i would reccomend is to record and loop the backing chords and then play either a C major or G major scale over them and see which you think sounds better- remember to lean on the root note of the scale alot for a better comparison.

I'd say that generally if i have a progression that could fit in to two keys i listen for the chord that resolves it which is (most of the time, not 100% of the time) the first in the progression.

thank you DR.. because you just touched the subject.. i want to ask you about the scales.. im still pretty new to this, but i was thinking about playing the minor pentatonic scale.. and not the major scale, because i would think that it did not work on the minor chords..?

so i guess my question is.. when choosing a scale, should i look at the notes in the chords rather than Major vs. Minor?
(i only know the minor /major pentatonic, blues and major so lets stay with these for the sake of understanding)

QUOTE (wrk @ Jul 30 2008, 11:09 AM)
As you said, the difference between C and G major scale is the F or F#.
The notes of your chord (1st, 3rd, 5th) progress does not include an F or F# somewhere... by now

As an add on DR's advice ... when you play/record your progression try to add the 7th (especially on the G major chord) and you will quickly notice in which key you are.

Thank you, i will try it.. if i haven't narrowed it down to one key, is adding the 7th always an option to quickly notice it?

and can either of you explain exactly when a key is a minor key??

Thank you both again
DeepRoots
QUOTE (-Zion- @ Jul 30 2008, 10:21 AM)
thank you DR.. because you just touched the subject.. i want to ask you about the scales.. im still pretty new to this, but i was thinking about playing the minor pentatonic scale.. and not the major scale, because i would think that it did not work on the minor chords..?

so i guess my question is.. when choosing a scale, should i look at the notes in the chords rather than Major vs. Minor?
(i only know the minor /major pentatonic, blues and major so lets stay with these for the sake of understanding)

Basically- a scale whether its major or minor- can be "harmonised". This means turning the group of 7 notes into a group of 7 chords. When we harmonise the major scale, we get major and minor chords (and a diminished chord- no need to discuss that here too much though).
Also a minor scale will harmonise and get major and minor chords too.

So a major scale wil work over minor chords, in the case that it is one of the chords you get from harmonising that particular scale.
(all this is in Andrew's chords for scales lesson)

We lay out the scale, pick a note then skip a note, untill we have 3 notes:(check the above lesson for how to get to this next step)

We get: C major, D minor, E minor, F major, G major, A minor B diminished

So as you can see- all the chords in your progression are in that^^. And we produced those minor chords by harmonizing a major scale, so yes! you can use a major scale over a minor chord- if the chord can be taken from that particular scale.

This may seem a bit off topic- but when you get really used to harmonising scales like this- you'll get to the point when you can quiclkly decide what chords will work over any scale you like- and also you will recognise chords as groups of chords from a certain scale- making scale choice quick and easy
Read that lesson though! It's a great one

QUOTE (-Zion- @ Jul 30 2008, 10:21 AM)
and can either of you explain exactly when a key is a minor key??

Again, minor scales can be harmonised just like a Major scale and will have it's own set of chords etc (check the lesson).

Adding this knowledge of harmonising scales along with using your ear to identify the root/home/resolving note/chord will give you a powerful tool for working in this kind of "puzzle".

My short answer would be to use C major scale of your chords, my longer answer would include identifying the tonic (root of the scale) chord and also learning how to harmonise a scale for a true understanding of how scales and chords work together.
wrk
DR said everything ...

Two approches were helpful for me to learn how chords and scales work together:

1. Analyse .. exactly as you did by taking your fixed progression. With the help of your diagram its easier at the beginning, extend your diagram with chords (chord notes), this will give you an idea about harmonizing the scale like DR explained.

2. Let your ears decide ... play and modify the progression by changing order of the chords or by adding some notes which sound good to you, but don't forget to analyze it again.

It will be more and more clear for you, very quickly you will not need a diagram anymore ... then you know you did progress

-Zion-
thank you both.. i believe i still have some work to do in the theory department..
Andrew Cockburn
Um, hello? Guess I'm not needed around here any more Wrk & DR did a great job of answering that one!
kevvyg
Hi, on the subject of key signatures, I learned something which may be of help!

The order which the sharps appear on the stave is: Fat Cats Go Down Alleys Eating Birds (FCGDAEB).
The order which the flats appear on the stave is: Battle Ends And Down Goes Charle's Father (BEADGCF).
To work out the key from a key signature:
If the signature contains sharps, take the last sharp, and go up 1 semitone. (1 sharp on the 'F' line gives F# + 1 semitone = G major, G A B C D E F# G).
If the signature contains flats, the last but one flat (reading left to right), IS the key. (2 flats, one on the B line, and one on the E line. The last but one is on the B line, so the key is Bb Major, Bb C D Eb F G A Bb)
Hope that helps!!

Kevin
I suppose the two examples above could just have easily been E minor and G minor, but probably best to ignore that for now...

QUOTE (-Zion- @ Jul 30 2008, 09:15 AM)
hi Andrew.

I have a question about finding the key in a song.
Lets say the song has this chord progression: C, G, Am, Em
it's a fairly simple chord progression, but i just want to make sure i understand correctly..

Now i have this Major scale chart, and plotting the chords into it, i have now narrowed the list of possible keys down to three.. C, F and G.

Is this a correct way of figuring out the key of a song? it seems to make sense to me, but i just want to make sure..

And another question: What determines whether the key is major or minor??
i dont suppose that all chords in the progression should be minor chords.

Thank you very much.

I spent ages trying to work this stuff out, so I might as well pass on the info!
The notes of a major scale have the interval pattern TTSTTTS, so C major, for example, is C D E F G A B C.
The triads (3 note chords) built on each note are MmmMMmd, where M is major, m is minor and d is diminished.
So - the chords built on C major are Cmaj, Dmin, Emin, Fmaj, Gmaj, Amin, Bdim.
Add to this the info about the chord notes, (in this case, CEG, DFA, EGB, FAC, GBD, ACE, BDF), and you're in with a good chance of sussing out the key.
In this case, it's probable that you're in C major, (or A minor - it depends on the 'feel' of the piece, and how the chords are arranged), but it could be in G major (or it's relative minor E minor), as the F# wouldn't show up in the chords you've given us. G major is G A B C D E F# G, so the chords that would show F# would be B minor, D major, and F# diminished.
Same for the E minor scale. F major's not in there at least, as you have Emin, as opposed to Edim. So, it's still a bit of a mystery I'm afraid, but you get the idea, I hope.
And, having said all that, someone could quite possibly write a song in a certain key, and just lob a non key chord in for a laugh. It wouldn't change the key, it would just be an 'odd' chord!

ps, A chord is major if the distance between the root and 3rd is 4 semitones (major 3rd), and is minor if it's 3 semitones (minor 3rd)
Fuebob
Hi mates

Sorry for digging here

I've got a dumb question :
How is it supposed to work for a backing track composed only by power chords (root, third, fifth) or composed only by some notes ?

Example 1: Metalcore riff :

Drop C notes Riff :

D--|-----------------------------------------------
A--|-----------------------------------------------
F--|-----------------------------------------------
C--|-----------------------------------------------
G--|------8-----7------8---5----------5-7-------
C--|-0-0---0-0---0-0---0-----0-0-0------------

D--|-----------------------------------------------
A--|-----------------------------------------------
F--|-----------------------------------------------
C--|---------------------------8-7-5-7-----------
G--|------8-----7----5-----------------8-7-5----
C--|-0-0---0-0---0----0-------------------------

Am I good if I say :
We have these notes : C, D, D#, F, G, G#

These notes are in the Aeolian mode of C.

So the scale i would play on should be C minor scale, right ?

Example 2: Backing track with power chords :

Drop D Power Chords Riff :

E--|-----------------------------
B--|-----------------------------
G--|-----------------------------
D--|-0--0--0--0---8--8--8--8-
A--|-0--0--0--0---8--8--8--8-
D--|-0--0--0--0---8--8--8--8-

E--|-----------------------------
B--|-----------------------------
G--|-----------------------------
D--|-5--5--5--5---3--3--3--3-
A--|-5--5--5--5---3--3--3--3-
D--|-5--5--5--5---3--3--3--3-

Am I right if I say :
The notes i keep are : D, F, G, A#

These notes fit in Aeolian mode of C too (but not the thirds of these chords).
BUT, it also fit the Aeolian mode of D and G (where the third of each power chords, fit too).

In that case how can I know on which one i should work on ?

Many thanks for your help !
Andrew Cockburn
Hi Fuebob -

You need to keep in mind the root notes of these chords which are a clue to the tonal center. Both of those riffs (as is often the case) seem to me to start with the first root note as the tonal center - C in the first, D in the second.

For the first rift, that confirms what you already said - this seems to be a C minor riff.

For the second riff, the first root note is D, meaning we are looking for a scale that starts with D and incorporates F, G and A# as well.

D aeolian is D, E, F, G, A, Bb, C D - since Bb is the same note as A# it fits in nicely.

The reason we would say Bb and not A# in this context is that D Aeolian is a mode of F major which is the scale we get when using one flat (Bb), but that is really just a matter of notation and doesn't change our conclusion.

To answer your general question - the fact that we don't have any thirds here in theory gives you a little more leeway in scale choice but since power chord riffs are usually painting around full scales in the actual songs anyway, in practice the 3rds are kind of assumed and you end up with the same result.

One way to confirm this is to not just listen to the riff, but also any bass and melody line that goes with it - they will often incorporate other missing notes of the scale and give you a fuller picture.
Fuebob
QUOTE (Andrew Cockburn @ Mar 23 2016, 09:35 PM)
Hi Fuebob -

You need to keep in mind the root notes of these chords which are a clue to the tonal center. Both of those riffs (as is often the case) seem to me to start with the first root note as the tonal center - C in the first, D in the second.

For the first rift, that confirms what you already said - this seems to be a C minor riff.

For the second riff, the first root note is D, meaning we are looking for a scale that starts with D and incorporates F, G and A# as well.

D aeolian is D, E, F, G, A, Bb, C D - since Bb is the same note as A# it fits in nicely.

The reason we would say Bb and not A# in this context is that D Aeolian is a mode of F major which is the scale we get when using one flat (Bb), but that is really just a matter of notation and doesn't change our conclusion.

To answer your general question - the fact that we don't have any thirds here in theory gives you a little more leeway in scale choice but since power chord riffs are usually painting around full scales in the actual songs anyway, in practice the 3rds are kind of assumed and you end up with the same result.

One way to confirm this is to not just listen to the riff, but also any bass and melody line that goes with it - they will often incorporate other missing notes of the scale and give you a fuller picture.

Thanks so much to the Master of Theory.

Many thanks Andrew!
Todd Simpson
Great answer from ANDREW!!! Nice That should go in the Wiki!

Todd

QUOTE (Fuebob @ Mar 23 2016, 05:34 PM)
Thanks so much to the Master of Theory.

Many thanks Andrew!

Andrew Cockburn
QUOTE (Fuebob @ Mar 23 2016, 06:34 PM)
Many thanks Andrew!

Happy to help - although it feels weird replying to a post I wrote about 9 years ago

QUOTE (Todd Simpson @ Mar 23 2016, 07:38 PM)
Great answer from ANDREW!!! Nice That should go in the Wiki!

Thanks Todd!