Question about Triads.

[Feda]

Let's say I have a Bbmajor scale. The seventh degree would be A. Now, are the triads:

A-Cb-Ebb-Gb

Since it's the seventh degree that would a Amin7b5 chord right? Whats bothering me is that the Bbmajor scale has an Eb in it. Does this mean that I have to "flatten" it once more or just leave it as it is because it already is flat?

Hope you understand my question..

[Ed Fuqua]

If you have a key, write it out over and over

Bb C D Eb F G A Bb C D Eb F G A Bb C D Eb F G A Bb


Now pick the 7th degree of the scale
A
now pick a note that's the 3rd degree away
A Bb C
then pick another note that's the third degree away
C D Eb
then pick another note a 3rd degree away
Eb F G

So whadya got? A C Eb G = Aminor 7 flat 5

I don't know where you're getting alla this "flatting" from...

You ALWAYS ALWAYS ALWAYS use scale degrees present in the key signature, you don't need to add accidentals to get diatonic chords.

The other way to look at it is building the chord from it's nomenclature = A minor 7 flat 5

so you need an A minor triad = A C E
you need the dominant 7 = A C E G
and then you need the flat 5 = A C Eb G

Clearer? You want to do an Bb-7b5 for me?

[Feda]

Can it be Bb-Db-E-Ab?

Thanks for explaining!

[Tash]

Originally Posted by Ed Fuqua

The other way to look at it is building the chord from it's nomenclature = A minor 7 flat 5

so you need an A minor triad = A C E
you need the dominant 7 = A C E G
and then you need the flat 5 = A C Eb G

One technical error with this: there is no such interval as a "dominant 7". You are using a Minor 7th interval (1 whole step below the octave or root of the chord). A dominant 7 is a type of chord, specifically a Major triad with a minor 7 added. its called the Dominant 7 because it only occurs naturally on the dominant (5th) pitch of the major scale.

Also the chord you are building is called a a half-diminished 7th chord, because it contains a diminished triad (root, minor 3rd and diminished, or flat 5th) with a minor 7th added. A fully diminished 7th chord would have a diminished 7th instead (and is composed entirely of minor 3rds).

[Suckbird]

Ow, now i see how bad my theory is.

Never heard of a Amin7b5 before...

[Ed Fuqua]

Originally Posted by Feda

Can it be Bb-Db-E-Ab?

Thanks for explaining!

Almost. You want to remember about enharmonic spelling. The fifth degree of some kind of B chord is going to be some kind of F. B C D E F, right?

So enharmonically, Fb is the same note as E and is some kind of F which will be the 5th degree.

Half diminished and minor7b5 are interchangeable terms. Half diminished didn't even come into the vocabulary until mid 20th century.

[Tash]

Originally Posted by Suckbird

Never heard of a Amin7b5 before...

I really haven't either. Normally this chord is called a half-diminshed 7 as I explained above. I think the m7b5 name is more common in Jazz circles where chords are often refered to by their component intervals. This is probably due to the popularity of chords with added/altered tones in Jazz.

[Feda]

[quote=Ed Fuqua]Almost. You want to remember about enharmonic spelling. The fifth degree of some kind of B chord is going to be some kind of F. B C D E F, right?

So enharmonically, Fb is the same note as E and is some kind of F which will be the 5th degree.
QUOTE]

I thought about using Fb, but it's not a name I've seen that often, whilst E is Thanks a heap for this, it's gonna take a while for this to soak in..

[Richard Lindsey]

Originally Posted by Tash

I really haven't either. Normally this chord is called a half-diminshed 7 as I explained above. I think the m7b5 name is more common in Jazz circles where chords are often refered to by their component intervals. This is probably due to the popularity of chords with added/altered tones in Jazz.

IME m7b5 is more common than half-diminished 7--I wouldn't say the latter is "normal"--but there's absolutely no disagreement that they refer to the same thing.

[Peter Squire]

my old theory teacher used to go red and foam at the mouth if you ever said "half-dimished". he was adamant that it was always a m7b5, never half diminished. guess whatever works huh?

btw- what is the notational symbol for half-diminished?

[Richard Lindsey]

Originally Posted by southpaw1

my old theory teacher used to go red and foam at the mouth if you ever said "half-dimished". he was adamant that it was always a m7b5, never half diminished. guess whatever works huh?

btw- what is the notational symbol for half-diminished?

A circle with a slash through it.

[Tash]

A circle, by the way, is the symbol for a fully diminished 7...get it, line through it, half, no line, full....

Question: when you are labeling chords by interval collection (m7b5, Dom7b9, etc.) what's the convention for labeling the various inversions? "Dominant 7, Flat 9 four three" is a lot more clumsy on the tounge than "Five-four-three, flat 9".

[Richard Lindsey]

Originally Posted by Tash

A circle, by the way, is the symbol for a fully diminished 7...get it, line through it, half, no line, full....

Question: when you are labeling chords by interval collection (m7b5, Dom7b9, etc.) what's the convention for labeling the various inversions? "Dominant 7, Flat 9 four three" is a lot more clumsy on the tounge than "Five-four-three, flat 9".

Technically, as I learned it anyway, the circle should mean a diminished *triad*--1 b3 b5--rather than a diminished 7. So Ao would be A C Eb, and Ao7 would be A C Eb Gbb. Though the circle alone is not infrequently used for dim7 in my experience. So the half-diminished 7 would be slash-o 7. Though again, I've seen the slash-o by itself for that chord.

As far as the inversions go, I forget what the technically most correct way might be--I probably did know it once!--but what I always see, and what seems easiest to me, is just to have the name of the chord, followed by a slash and the name of the desired bass note.

[Classical_Thump]

Well the inversion is listen as one or two numbers just on the left hand side of the cord. The most common are triads in first inversion (ex Amaj 6) or say a seventh chord in first inversion (Amaj7 65)- now the five would be under the six, sort of looking like a fraction but without a the bar between them. There are numbers like this for all inversions but I dont have time to type em all out now

[Tash]

Chord inversion names:

First inversion triad (third in bass): ChordName6
Second inverstion triad(fifth in bass): ChordName64
First inversion seventh (third in bass): ChordName65
Second inverstion seventh(fifth in bass): ChordName43
Third inversion seventh(seventh in bass): ChordName42

All refer to the intervals above the lowest note (not the root note).