You said: I want to know that when I do songwriting in a certain chord progression within a key, I want to know, from which neighbor scales can I borrow chords, or which chord progression could I jump into?

I'm assuming here you don't necessarily want a "permanent" key change....just a chord (or a few) outside the scale.

Look into Secondary Dominants. That is taking any note of the scale, looking at it's scale and using the V7 of that scale. ex: Key of C--the 5 is a GMaj. In the Gmajor scale, D7 is the V7. That's why D7 sounds good in a song in C even though all the notes are not present in the C scale. The Secondary dominant of the V is most common, but you can use any note of the scale to find one. I'm reasonably sure.

Look into parallel modes--Dorian, Phrygian, Lydian etc. Ex: If you are writing in C major, you can introduce any chord derived from a C Dorian scale--Cm Dm Eb F Gm Adim Bb. There are 6 useful alternative modes of each major scale (plus Locrian) which are perfectly usable even if you don't want to actually do a full-on key change. This is a great way to introduce tension or just to simply change the mood for a bar or a few (or more than a few, like a genuine change up middle 8).

This is technically called "modal interchange". I've got a chart hanging on my wall made by the fellow from my second link above, but no doubt visual aides are available online to help you.

That's a couple of direct answers. You're likely way ahead of me understanding these, but maybe just an introduction will get you moving quickly.

EDIT: On reflection, I realized the bit about secondary dominants is likely covered with your "circle of 5ths" thing. I haven't found a useful tutorial for myself, especially since different "explainers" seem to use different tools and in different ways. BUT, I wonder if you have thought about taking the second "tip" a further step...using secondary dominants of chords from parallel modes?


Last edited by Tangmo; 08/03/20 08:48 AM.
BIAB 2021 Audiophile. Windows 10 64bit. Songwriter, lyricist, composer(?) loving all styles. Some pre-BIAB music from Farfetched Tangmo Band's first CD. https://alonetone.com/tangmo/playlists/close-to-the-ground