Can I use a B7 chord voicing in the key of Bm?

Question

Hi just starting out in guitar and songwriting. I was told that my song is in the key of Bm . In my Chorus section, my chords are Am-Dm-Bm-Am-F-F# and I wanted the last chord (on the last word I'm singing), to have a 'voicing' of the B7 chord,as I'm going 'up' from F to F# and this 'sounds' right to me but was told this is not in the key of Bm and I'm not allowed to do this.

The 'voicing' is: A string-2nd fret + D string-1st fret + G string-2nd fret which I was told is a 'voicing' of the B7 but only 3notes. I'm sort of confused as I'm of course just starting out. Does anyone know if this 'voicing' can still be used in this key (Bm) ?

PS. forgot to mention in my verses, the progression goes:

Bm-Fmaj7-Bm-Fmaj7-Em-C and then again was looking to use B7(B Dom 7) (B-D#-F#-A in this chord), as the last chord in the verses, before going to the Chorus (which begins with F)

The song which is a 'Broadway' ballad type of tune, ends with a Bm chord.

Answer 1

This is an interesting example, because none of these chords are in a direct sense “in bm” (except the bm itself)!

• am has a C (bm-natural: C♯; would make it A)
• dm has an F (bm-natural: F♯; would make it D)
• F has an F and a C
• F♯ has an A♯ (bm-natural: A; would make it f♯m).

The F♯ however is a very idiomatic chord for the key bm, namely it is the dominant, which is almost always played as a major chord (very often as a seventh chord, a dominant seventh). In fact the F♯ chord in the verse is largely responsible for making it clear that the key is in fact bm: a dominant has the strongest key-establishing effect, more specifically, the resolution F♯-bm has a strong finality, it's an authentic cadence.

And that is quite a good primer for the discussion if some other chord may be appropriate: is is appropriate if it fulfills a useful role. In that chorus, I think the roles are mainly concerned with the chromatic line you (presumably) play on the high E-string, namely E-F-F♯, which you use quite neatly in two different harmonisations, once ending in the tonic, the second time in the dominant (which is a very common trope):

X:1
L:1/2
M:C
K:Bm
%%score T1
V:T1           clef=treble-8
% 1
[V:T1] "am"[A,EA=ce] "dm"[DAd=f] | "bm"[B,FBdf]2   | "am"[A,EA=ce] "F"[=F,=C=FA=c=f] | "F♯"[F,CFAcf]2

Actually, because it's a rising chromatic line, this would arguably be more natural to read it enharmonically E-E♯-F♯, and in particular in the second round the E♯ makes a lot of sense as the leading tone of a secondary dominant which brings you to the F♯. Such leading tones are the bread and butter of classical music, and still very relevant in pop.

Now the perhaps problematic thing with B⁷ is that, being a seventh chord, it would also be very likely perceived as a dominant of sorts – but where does it lead? I certainly wouldn't expect it to lead to anything related with bm, nor with am. That may be the reason you where told you can't do that: B⁷ seems to set up an expectation that is then disappointed.

Now, that kind of thing too can be ok, if it has a useful effect. What B⁷ implies is that you want to modulate to em (of which it is the dominant). Going to em might actually work very well for a chorus, it kind of opens up the mood wide, revealing that all the verse bm actually wasn't really the tonic, but just the dominant-key!
OTOH, am is the subdominant of em. Dropping from the dominant to the subdominant is a bit of an odd thing to do – it gives an impression of “wait a moment, there's one thing I forgot...”. That's definitely not the feeling I would associate with a chorus section, however it could work well as a pre-chorus bridge. Either way however, you should do something with the harmonic movement. First setting up B⁷ which seems to go to em, and then immediately following with that am-dm-bm chromatic thing slaps the listener with two very different, unrelated if not outright contradictory ideas. The only thing that could tie it together would be a melody that makes it clear why. But it might instead end up sounding just jarring / unsatisfactory.

Where B⁷ could work better is in the end of the chorus, because it would continue this idea of using the E-F-F♯ chromatic over different harmonic contexts.

X:1
L:1/2
M:C
K:Bm
%%score T1
V:T1           clef=treble-8
% 1
[V:T1] "am"[A,EA=ce] "dm"[DAd=f] | "bm"[B,FBdf]2   | "am"[A,EA=ce] "F"[=F,=C=FA=c=f] | "B⁷"[B,^DABf]2

If you then follow this with the next verse's bm then this too will be a disappointment of dominant expectation, of sorts, but at this point it might make a lot of sense dramaturgically: it's kind of saying “we see the finish like, but no, the battle isn't won yet, here's why...”.

Answer 2

The other thing that would help here is to be able to listen to the melody line over the said chord sequence. That would give a closer idea as to what the key actually is, and would also provide clues as to how the transition between verse/chorus works in this song.

The voicing of B7 is fine - there's a root (B), maj3 (D#) and a b7 (A). As you're fairly new to this, it's a common way to voice a chord - leave out the P5, exactly what has occurred here.

That B7 nine times out of ten, leads to an E. Either E major or E minor, in almost every song it's found in, except maybe blues. It does that, as mentioned in other answers, as it's the dominant of E. However, here, it goes off somewhere else, and the listener is denied the pleasure of thinking 'I know where this is going!'

A B7 chord in a Bm key isn't that rare, I often use it just before the aforementioned E/Em chord in a song. It 'sets the scene' for the E/Em. But the song's key may well not be Bm. But even if it was, there are no rules saying other non-diatonic chords cannot feature in the song. Secondary dominants had a mention, so the B7 could be construed as one, but I'd expect it to go through to an E something, then onto Am, which seems more likely as the key. It doesn't though...I wonder whether B7 will be the last chord of the song. If yes, then it will also leave the listener dangling - rather like a question mark.

Answer 3

Of course, the less technical but most helpful answer would be “you can do whatever you want.” While that’s true, I think there’s even more that we can learn from your example.

To expand on the idea of your post, you are correct that the chord B7 is not diatonic to the key of Bm (specifically because of the D#, that third of the chord). We would consider this a borrowed chord from the key of Em, which is only separated by one note from Bm, so the two keys are closely related. Implied in that statement is that B7 would resolve nicely to Em, which is in the key of Bm. Also, in jazz it’s very typical to go from a Dominant 7 to a minor 7 on the same root note. So B7 followed by Bm (or Bm7) isn’t even that uncommon. And in plenty of pop songs in the style of Paul Anka and Burt Bacharach you’ll find the same type of harmonic treatment.

So... just go for it!

EDIT: So I went back over the original question for context of the full progression. Here's what we can say:

The B7 that precedes the Am is a secondary dominant. Even though it does not resolve to E or Em, Secondary dominants are dominants of single pitches, not chords, although that pitch is most commonly the root of a triad or chord. I have verified this with the dean of my undergraduate school of music.

The B7 that precedes the Bm is the one that prompted all the discussion below. Perhaps it's more appropriate to call it a borrowed chord from B mixolydian if it's a borrowed chord. Calling it a borrowed chord from Em (as I did originally) would be considered secondary mode mixture, a concept which I think seems evident enough to see in practice (as in this progression) but the definition for which would likely only confuse the OP. I have also run this example past Doctorates of Music in Composition to verify what I have written above. But I will again fall back to the original answer above, as the simplest answer is often the most effective:

Do what you want -- expressed colloquially, and through common sense, the B7 before the Bm basically functions as a coloration of the Bm chord. Chords like this are most often taken (borrowed) from keys that are as closely related to the key of the song as possible. Em is closer to Bm than B mixolydian is to Bm.

Pedantic over analyzation like this can ruin the creative process. If you hear a chord that sounds good - play it. Someday people will be arguing over what to call your use of some kind of quintal sub-dominant of the parallel major key... and you'll just be writing music.