Kido's Practice session guide

As I see it, the only way to get to modes is through the major scale, which
consists of two adjoining tetrachords.
Take the tetrachord GABC - it's the upper half of the key of C (CDEFGABC) and the lower half of G (GABCDEF#G). DEF#G is the lower half of D (DEF#GABC#D), etc.

what the hell is a tetrachord?

Basically, it's half a major scale. C-D-E-F is one, and G-A-B-C is another.

So I've read it to be 4 notes covering a perfect fourth. Maybe it's me but why call it a tetrachord instead of just half a scale? Can it be anything else? Or does it always revert to half of a scale?

I just wanna know how they are put together, I though that you just combine them but I can't see how they are combined?

I should have jumped on this earlier, my apologies, noone let me know this thread was active. Well lets get to it then.

I see tetrachords as a very useful tool:

A.) Because they divide the amount of information in half, because an 8 tone scale fingering is reduced to 4 notes. And small amounts of information are easier to ingest. This does not make them less useful for learning scales, but it is much easier to sit down and learn 3 possible tetrachord fingerings and combine them at random then it is to memerize five (8 Tone) scale fingerings and risk overloading your brain.

B.) Permutation, my favorite form of practice, involves taking numerical figures and rearanging them at random to find all possibilities for combination. Permutation is almost impossible to acheive with a seven (or eight with the tonic) tone scale. However, with tetrachord fingerings it is very easy to sit down and go through the combinations (only 24) and really get to know the pattern your working on. This is in opposition to simply sitting down and doing scale runs for hours, and lets face it, who wants to listen to someone play a scale up and down in a song. Not me. Here is a chart I made for permutation, simply assign 1-2-3-4 to the tones of the tetrachord (also 1-2-3-4) and you will be playing some very interesting tonal combinations, youll definately suprise yourself if you havent yet tried it.

This was made originally for 7th chords, but they also are constructed of 4 tones so the outcome is exactly the same.

1-3-5-7 would translate with tetrachords to 1-2-3-4, obviously I went through the trouble of translating chord tones so people could be counting them as they arpeggiated. But Im sure you get the idea....

So anyway, how do we combine them??? Thats easy, the best way to do so is to take a look at the mode your trying to play (in complete form) and figure it out for ourself...if this is a little too tricky for you ill link you to a thread I have containing all of the caged format scale fingerings and you can see how the tetrachords construct them.....

Heres the link:

https://www.guitarnoise.com/forums/viewtopic.php?t=9403

You can observe the tetrachords and how they are seperated by looking at the way the scales are constructed. And dont just blow this off...take a serious look....look at the first 4 notes of each seperate mode, take note of the whole step or half step difference and then the second tetrachord attatched.

This can be really difficult to take all in at once, but sometimes its nice to have your mind be ahead of your technical ability because youll always have a new strategy to practice. The worst thing is when you run out of ideas and stop playing because you dont know where to go next.

The info Ive provided should keep a pro of 40 years occupied to say the least. None of it can be mastered, and theres always somewhere new to go. But start today......

Good luck everyone...

Kido

Useful thing about tetrachords:

The second tetrachord in a major scale (G-A-B-C for example) is the first tetrachord of the scale of the key with one extra sharp

The first tetrachord of the major scale (C-D-E-F for example) is the second tetrachord of the scale of the key with one extra flat

It's not so easy with minor keys, though.

Best,

A :-)