The Avoid Note

First a disclaimer - I'm not one for doing a lot of studying of scales and modes so this is the first time I've ever heard of "the avoid note."

That being said, I think you have to be careful with a concept like this. Ultimately it's the chord progression and the song and how the solo plays off of both those elements that determines whether a note is going to sound good or bad in a solo. Thinking that the scale or mode comes first is what leads many guitarists to use the pentatonic scales to distraction and miss out on a lot of colors available to them with full major scale and modes.

If a song is a ballad type song in the key of C, for instance, why on earth would you want to avoid the F note? Chances are likely you're going to run into F chords galore in the chords used in the song. Even when you don't, the F note sits nicely as a sus4 over the C chord and even works as a dominant seventh when played over G. It's the minor third of Dm, which you're fairly likely to come across as well.

Your best guide for telling you what is an "avoid note" are your two ears. Even there, people will find differing opinions on their like or dislike of particular dissonances. And then there may also be instances where a sharp dissonance of a prolonged number of beats may be just what the mood of a song calls for.

I'm not sure that this is especially helpful in your search for more information on this "avoid note" topic. Hopefully Tom or Fretsource or David will weigh in with more insight on this matter.

Peace

Don't think of avoid notes in terms of the scale - think of them in terms of the chord. And frankly, "avoid" is a bad term... but "be careful with notes" don't have the same ring.

If your chord is a C major (or Cmaj7, C6, etc), the 4 creates a flat nine interval with the third in the chord. That's a dissonant interval, but you're playing it over a stable harmony. And that means you can do one of two things:

1. Avoid it (the easy way out)
2. Be careful with it. That means not putting it on the downbeat, keeping it's duration short (half a beat or less, generally), and doing something with it that makes sense - using it as a passing tone, an appogiatura, etc.

Basically you want to keep the melodic attention off the note. But that doesn't mean you can't use it at all.

And of course, once you change chords, it's no longer an "avoid" note. David pointed out that F will be used a lot in a song in C... it's just that the F will be used mostly against F major, Dm, or G7 chords, since it's a chord tone there. So you'll have different avoid notes at different times.

You'll most often see the term used in conjunction with scales. But really, an avoid note could be any note that creates a dissonance with a stable chord - Db would also be an avoid note over C major (as would Eb, Gb, etc)

Thanks a lot for the clarification !!
Yes exactly, more than a note that you should 'avoid' it is mostly a note that you should take care of because it is sensitive.
By the way I'm copying a comment that I read from a jazz forum, below:

'The Berklee definition of an "avoid note" is a note that's a half step from the triad. 9 on a major 7 chord is a whole step above 1, 13 is a whole step above 5, but 11 is a half step above 3, and so creates a lot of unstable tension that isn't fit for a harmonic voicing (but of course is plenty useful melodically). Exceptions include dominant seventh chords (b9 and b13). It originally was a term that should was used when exploring voicing possibilities in arranging and piano/guitar, not linear melodic development. Analyzing melody/harmony relationships in solos can sometimes be a real pain to people who misinterpret the term. Many people around here (Berklee) prefer then the term "harmonic avoid note" or "scale degree" to clarify.'

All the best