# How to figure out which scale to play a specific chord in? [duplicate]

I am quite new to music theory so I might have the wrong view but from what I learned:

With each key on the piano (ABCDEFG) you can construct a scale. So the E major scale, E# major scale, E minor scale, etc. Then in a specific scale you construct chords as well.

I was watching a video and the person in the video says he's going to play the Em7 chord. My question is when someone says play the Em7 for example, how do you know which scale to play the Em7 chord in? For example, I can play the Em7 chord in the E major scale, E natural minor scale, etc.

With each key on the piano (ABCDEFG) you can construct a scale. So the E major scale, E# major scale, E minor scale, etc. Then in a specific scale you construct chords as well.

This sounds like you're talking about the idea of a song being in a key, which is defined by the root note (e.g. E) and a type of scale (major or minor).

When someone says play the Em7 for example, how do you know which scale to play the Em7 chord in?

That question doesn't make much sense to me. It's a bit like asking "when someone says a word, how do you know what they're talking about?". (I'm not saying this as a criticism - just in the hope that it will make things clearer!)

When you play a single chord, you don't have to know what scale to play it in (or what 'key' to play it in) - just like it's possible to say a word without knowing what topic you're talking about.

However, if you hear someone play the E minor 7th chord, it is possible to guess what key they are playing in. Because that chord contains E, G, B, and D, it might be that they're playing in a key with those notes in:

C Major / A minor
G Major / E minor
D Major / B minor

It might not be that they're playing in those keys, because it's possible to use notes in a song that are outside 'the key it's in'. But those are good guesses.

• Oh ok, it's more clear now! Thank you! I don't know if I am missing something here, but on every scale the E minor 7th chord will have the notes EGBD? Shouldn't it be E-Gb-B-D since Em7 means the flat the third? – CapturedTree Jan 7 '18 at 18:25
• @ToothyRel On every scale, E minor 7th chord will have the notes EGBD. When people say that a minor chord (or scale) should have a "flat" third, they mean it's a semitone lower (flatter) than the major chord would be. The notes in an E Major chord are E, G#, B, and the (major) third there is the G#. If we make that G# a semitone flatter, we get E, G, B , which is an E minor chord. – topo Reinstate Monica Jan 7 '18 at 18:36
• Oh ok! I understand it now haha! I think I just have to practice my chords on the piano physically now. – CapturedTree Jan 7 '18 at 18:57
• @ToothyRel BTW when I said "on every scale, E minor 7th chord will have the notes EGBD" - I should have probably just said it even more simply: "an E minor 7th chord will always have the notes EGBD". – topo Reinstate Monica Jan 7 '18 at 19:00

I suspect that you are mixing up scale with key. Em7 will always be composed of the notes E, G, B and D; all or some of these notes may or may not be in the underlying key signature. The chord informs which notes would sound good when played over the chord - for example, the run E F# G would sound harmonious over an Em chord, even though there may be a G# in the key signature (for example, B major).

When asked for an Em7 chord, play the notes E, G, B, D. That's it.

Now, if you're playing the musical game of 'improvise a melody over these chords' you might want to know what OTHER notes might sound good. Now context starts to matter. Those notes, E, G, B and D fit in to several major and minor scales, and a whole lot more 'modes'. Scales that 'fit' include C major, D minor, E minor, G major, A minor... It's good to use a scale that also 'fits' with the chord before and the chord after. It's also good to use one that doesn't - contrast is as valuable as uniformity.

Theory shouldn't be used to tell you what notes and chords you MAY use. Read, play and study lots of music by composers and musicians you like. Use theory to explain and categorize what they DID do.