Two novice questions

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James_J
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Two novice questions

Post by James_J » Sun Jan 07, 2018 10:31 pm

Hi all,

Just a couple of novice questions:

1) Can anyone describe (or point me to a website) what a major, minor, 7th and diminutive chords actually are? For example what's the difference between C Root and C Major?

2) What types of voices are suited to different styles/national types of music?

Many thanks,

James

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Re: Two novice questions

Post by Geronimo » Sun Jan 07, 2018 11:24 pm

a) The Stradella bass has various reed sets containing one octave each. Those are split into bass reed sets and chord reed sets. The registers you use select which reed sets are active. When using a bass note, all notes of the same note name sound in all active reed sets (one example exception: a Gola does not couple its bass notes into the chord reed sets; instead it has a third bass reed set in Master mode to keep the balance between bass and chords).

When using a chord, all notes of the note names corresponding to the chord sound in all active chord reed sets. For example, the reed sets in a Morino (at least the old ones) start at E1, E2, E3, E4, E5. When pressing the C bass in Master register, you get C2, C3, C4, C5, C6. When pressing the C major _chord_ button in the Master register, notes E3, G3, C4, E4, G4, C5, E5, G5, C6 sound. When pressing C minor, you get G3, C4, E♭4, G4, C5, E♭5, G5, C6, E♭6. This jump of E to E♭ an octave higher is more disturbing when fewer chord reeds sound.

For that reason, on a typical Italian accordion (I am taking my Excelsior), reeds start at A1, A2 (bass reeds), F♯3, C4, C5 (chord reeds). Since the "contralto reed" has its octave jump at a different location than the higher reeds, the octave jump in the chord voicings is distributed across different note names.

C major is C E G (wherever the octaves lie), minor is C E♭ G, seventh is C E B♭ (a few older German accordions indeed sound 4 notes, namely C E G B♭ but that has gone out of fashion since you can easily replace it by playing both C and C7) and the diminuished is C E♭ A (which means that it works reasonably well as an F7 substitute as well).

b) the main differences is what kind of tremolo is used and whether reeds are placed in cassotto. Most folk music uses a three reed tremolo, but the exact tuning changes over regions and has also changed from the past since the necessity to cut through a whole dance floor purely acoustically is no longer given.

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Re: Two novice questions

Post by debra » Mon Jan 08, 2018 12:58 pm

Geronimo wrote:
Sun Jan 07, 2018 11:24 pm
a) The Stradella bass has various reed sets containing one octave each. Those are split into bass reed sets and chord reed sets. The registers you use select which reed sets are active. When using a bass note, all notes of the same note name sound in all active reed sets (one example exception: a Gola does not couple its bass notes into the chord reed sets; instead it has a third bass reed set in Master mode to keep the balance between bass and chords).
...
Very nice explanation of how the chords work (so I deleted that part).

The statement about the bass notes playing all notes of the same sound in all active reed sets is false not only for the Gola but for many other instruments with free bass (convertor or MIII).
When the base notes include the reeds from the chords you can easily tell: play C (base note) plus Eb minor (this forms a C minor 7 chord) on all instruments without free bass that I have seen the c minor button is "free" (meaning it can be pushed down without any force) because the Eb minor chord includes the Eb and G and the C base note was already pushed and includes the C from the chord. But... on the convertor instruments I have tried (both Bugari and Pigini actually) the C base note does not play all the C's included in the C major chord, so when C and Eb minor are played the C minor chord button is not yet "free". This is true even though The Bugari I tried does not have extra sets of reeds. The Pigini (Sirius bayan) is just like my AKKO bayan: it does have two additional reed sets for the base notes, so it does not use any chord reeds in its 4-reed base note setting.

None of this matters much for the novice questions, but it's an interesting topic by itself: the bass register mechanism can be kept simpler (and lighter) by not using chord notes for the base notes, but the extra reed sets add a bit of weight again.
Paul De Bra (not Debra...)
http://www.de-bra.nl

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Re: Two novice questions

Post by Geronimo » Mon Jan 08, 2018 2:45 pm

Well, I only have one free bass instrument to go by, and that is a special-built Morino. It's my guess that its mechanics in that regard match that of other free bass (literally on top of Stradella) Morinos in that respect. However, on my instrument I can activate about 7 chord reed sets (namely all notes from A2 to C♯6 and then the corresponding octave reeds from A3 to C♯7) and that makes the bass notes rather lacking in power when pitted against chord notes without such coupling. It also means that I can play organ music on the free bass manual and occasionally add pedal bass notes (from the Stradella bass) that have a lot more power due to that coupling.

I know that the precursor of my special instrument has only 2-row baritone basses (with a C system on the right) doubling as Stradella chord notes (with selectable chord octave) and requires the player to revert to the Stradella bass rows when descending in the bass octave (what a head-scratcher!), so I am pretty sure that it doesn't couple into the chord octave. Since it has fewer notes even in the baritone range, its tutti mechanism is also less drastic.

It would be really interesting to figure out who was responsible for how much of the design of my instrument and the choices taken.

I haven't actually played on converter instruments (Roland doesn't count). You may be right that the converter mechanism mandates different choices than the separate free bass mechanism, and even of the latter I have only one sample to go by, and an unusual one to boot. So if I got that wrong, I apologize.

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Re: Two novice questions

Post by Geronimo » Mon Jan 08, 2018 3:11 pm

debra wrote:
Mon Jan 08, 2018 12:58 pm
When the base notes include the reeds from the chords you can easily tell: play C (base note) plus Eb minor (this forms a C minor 7 chord) on all instruments without free bass that I have seen the c minor button is "free" (meaning it can be pushed down without any force) because the Eb minor chord includes the Eb and G and the C base note was already pushed and includes the C from the chord. But... on the convertor instruments I have tried (both Bugari and Pigini actually) the C base note does not play all the C's included in the C major chord, so when C and Eb minor are played the C minor chord button is not yet "free".
This is interesting as it means that C+em is distinguishable in sound from C+em+c and may, depending on the octave break, work better as Cmaj7 than the latter. Makes a difference for Turks Fruit, doesn't it?

As a note aside, my Excelsior has a Midi extension. The mechanic couplers from bass to chord note are obviously undesirable for producing Midi, so the Midi is generated only on the direct chord levers. But the springs holding the pallets would be the only active force pushing on those levers, so there is one additional spring for all chord button levers to make sure that if you press only bass buttons, no chord note will trigger in the Midi.

As a result, when you press C+em, the lever for the chord note c is no longer held by the pallet spring (which is opened via the linkage from the C bass button) and not held back by the common chord spring (which is already engaged because of the other chord notes). So it's free to fall in and cause a Midi sound at any time it considers suitable. Not good for stuff like Turks Fruit...

I seem to remember from some discussion on another accordion mailing list that somebody had exactly this problem with a reedless accordion bought in Italy, presumably using a standard Stradella mechanism. Now for that application it's beyond stupid not to remove those mechanical linkages.
None of this matters much for the novice questions, but it's an interesting topic by itself: the bass register mechanism can be kept simpler (and lighter) by not using chord notes for the base notes, but the extra reed sets add a bit of weight again.
I don't think the linkages add significant weight compared to reed plates, but they might interfere with the mechanism in general.

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Re: Two novice questions

Post by JeffJetton » Mon Jan 08, 2018 3:37 pm

I'll just explain the same thing Geronimo did, but in a slightly different way. Maybe it will help. Maybe not... :-)

Each horizontal row of six buttons in the left hand corresponds to a particular major key. So your "C row" (or, as I call it, the "C floor"... like the buttons are a leaning, 20-story office building!) is all based on the key of C major. Which is another way of saying that it's based on the C major scale.

If you move up one row toward your head (or "upstairs one floor") you're now on a row that is based on the key of G major and the G major scale. If you went downstairs from the C floor instead (toward your feet one row), you'd be on a row that's based on the F major scale. You get the idea...

Here's the trick: Each of the six buttons on each floor plays one or more notes from that's floor's scale. And the formula is the same on every single floor.

Short version... in order, moving out from the bellows, the formula is:
  • Note #3 from the scale
  • Root (1st note)
  • 1, 3, 5
  • 1, b3, 5
  • 1, 3, (5), b7
  • 1, b3, (b5), 6
Long version...
  • The regular bass button just plays the root of the scale, i.e., the first note. So the bass button on the C floor just plays a single C note. (Okay, it probably plays multiple Cs in different octaves, but the point is that it's only a single letter-name note.) Think of it as being like a bass guitarist or a tuba player who just plays a single low note.
  • The next "office" over on the floor (moving away from the bellows) plays that key's major chord. The chord is three notes at the same time, functioning sort of like a guitarist strumming multiple strings at different pitches. They're always going to be the 1st, 3rd, and 5th note of the corresponding major scale. So the C major button plays C, E, and G. (Again, these might be duplicated in multiple octaves, but it's still the same three basic notes. And they might be in a different order, such as G, C, and E... that's allowed. Still a C major chord!)
  • Moving over one more office, we have the minor chord. It's similar to the major chord, except the middle note is flatted. So it's the 1st note of the major scale, the flattened 3rd note, and the 5th note. For the C row that would be C, Eb, and G.
  • The next two offices both play chords that are technically supposed to be four-note chords. But most accordions only play the three "most important" notes out of those four. A full, four-note 7th chord starts out just like the major chord... 1st, 3rd, and 5th notes of the floor's major scale. But it adds an extra bit of spice to the chord with an extra note: The flattened 7th note of the scale. In practice, your accordion probably leaves out the 5th, so you wind up just with the 1st, 3rd, and flat-7th. So a "real" C7 is C, E, G, and Bb, but your accordion likely plays just C, E, and Bb.
  • Then there's the diminished chord, which it technically the 1st, flat-3rd, flat-5th, and 6th (or a "double flattened" 7th if you want to get picky) notes. Like the 7th chord, the dim chord usually omits the 5th, leaving you with just the 1st, flat-3rd, and 6th notes of the scale. So the Cdim button would probably play C, Eb, and A. (Because of this, the button also works as a min6 chord, incidentally.)
  • Going back to our bass notes, there's the counter-bass, which is always going to be the 3rd note of the floor's major scale. For the C floor, that's E.
Of course, this assumes you have a basic idea of what a major scale is. But if you don't, there's a formula for that too (and it's easy to learn).

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